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Documentation of the Web-Based ESAF System. What is new in the Web ESAF process? (662012) Do all Beamlines use the APS web system? How does the process work? How do I submit a...
Time Structure of the LANSCE Beam
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Beam One of the greatest strengths of the LANSCE facility is that it can produce proton beams with a wide range of time structures. Time Structure of the LANSCE Beam One of the...
Beam Time Allocation Committee (BAC)
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Time Allocation Committee (BAC) Time Allocation Committee (BAC) Charter Purpose: Allocates general user beam time by instrument to promote diverse and high- impact science and a broad-based user community to meet DOE and NSSD goals. Participants: BAC Chair (appointed by NSSD Director), Instrument Group Leaders, User Office Schedule: Tied to proposal calls - expected to meet at least 2 times/year with meetings scheduled about 6 weeks after the proposal call has closed and at least 1 month prior to scheduled operations. Process: 1. Instrument Group Leaders (with group members): a. Confirm feasibility (equipment requirements and instrument capabilities) and safe operations b. Review amount of beam time requested and adjust as needed with consideration for instrument and sample environment availability.
Laser Telecommunication timeLaser beam
Laser Telecommunication Experiment Laser time Laser beam intensity timeLaser beam Laser battery Laser connected to a circuit without a modulator. Bottom graph illustrates what happen when a modulating signal is superimposed to the DC voltage driving the laser Laser beam intensity DC Input voltage DC
La Rosa, Andres H.
Apply for Beam Time | Advanced Photon Source
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Apply for Beam Time Apply for Beam Time NEXT PROPOSAL DEADLINE: March 7, 2014 @ 11:59 PM (Chicago time) Submit Proposal » SEE ALSO: Calendar: deadlines, run & review dates Help Page: frequently asked questions, tips for success, common errors, blank forms, instructions Review Criteria Sectors Directory: check CAT websites for info about managed beam time The Run 2014-2 proposal submission deadline is 11:59 p.m. (Chicago time) March 7, 2014. The system will open to accept proposals beginning December 20, 2013. NEW USERS: to avoid delays and to make the most of your time on site, read Become a User. You must register as a user and receive a badge number before submitting a proposal. About the Beam Time Request Process All beam time at the APS must be requested each cycle through the web-based
NSLS User Access | Requesting Beam Time
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Requesting Beam Time Requesting Beam Time Use one of the following options depending on your research: General User Proposal General User proposals are peer reviewed for scientific merit by a Proposal Review Panel (PRP). General User proposals compete for beamtime with other General User Proposals based on scientific merit. Once the original proposal and beam time request is reviewed and rated in the PASS System, additional beam time requests can be submitted against the original proposal for its lifetime, a period of up to six cycles (two years). Data taken during experiments associated with a General User proposal is considered to be in the public domain. There is no charge for General User beamtime. Rapid Access Rapid Access proposals are a subset of General User proposals available for
Short rise time intense electron beam generator
A generator for producing an intense relativisitc electron beam having a subnanosecond current rise time includes a conventional generator of intense relativistic electrons feeding into a short electrically conductive drift tube including a cavity containing a working gas at a low enough pressure to prevent the input beam from significantly ionizing the working gas. Ionizing means such as a laser simultaneously ionize the entire volume of working gas in the cavity to generate an output beam having a rise time less than one nanosecond.
Olson, C.L.
How to Request & Access Beam Time | Stanford Synchrotron Radiation
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How to Request & Access Beam Time How to Request & Access Beam Time Step 1: Submit a proposal that summarizes proposed research plans. Step 2: Submit beam time requests. Step 3: Review & accept beam time allocations. Instructions for users allocated beam time on SSRL X-ray/VUV beam lines. Accept Beam Time & Submit Support Request Registration & Assistance User Agreements User Financial Accounts, Supplies, Gases, Domestic & International Shipments User Computer Accounts User Safety Preparing for Arrival/Lodging/Check-In Acknowledgements, Publications, Science Highlights & News Feedback Step 1: Submit a proposal that summarizes proposed research plans. Review the guidelines for proposals and scheduling procedures. Standard proposals can be submitted through the user portal three times each year:
Getting Beam Time at HFIR and SNS | ORNL Neutron Sciences
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Apply for Beam Time at HFIR and SNS Apply for Beam Time at HFIR and SNS Apply for Beam Time at HFIR and SNS 2014B Call for Proposals Proposal call 2014B All available beam lines will accept proposals through February 26, 2014 Beam time is granted through our general user program, which is open to all. In addition, we have opportunities for extended collaboration through programs such as internships and postdoctoral programs. The instruments at HFIR and SNS can be used free of charge with the understanding that researchers will publish their results, making them available to the scientific community. Our facilities are also available for proprietary research for a fee. ORNL User Portal The ORNL User Portal gives you access to all the resources you need as a new or returning user, such as the proposal system, data access and
Experimental Time Resolved Electron Beam Temperature Measurements Using Bremsstrahlung Diagnostics
Electron beam temperature, {beta}{perpendicular} (= v{perpendicular}/v), is important to control for the development of high dose flash radiographic bremsstrahlung sources. At high voltage (> 5 MV) increasing electron beam temperature has a serious deleterious effect on dose production. The average and time resolved behavior of beam temperature was measured during radiographic experiments on the HERMES III accelerator (10 MV, 50 kA, 70 ns). A linear array of thermoluminescent dosimeters (TLDs) were used to estimate the time integrated average of beam temperature. On and off-axis photoconducting diamond (PCD) detectors were used to measure the time resolved bremsstrahlung dose rate, which is dependent on beam energy and temperature. The beam temperature can be determined by correlating PCD response with accelerator voltage and current and also by analyzing the ratio of PCD amplitudes on and off axis. This ratio is insensitive to voltage and current and thus, is more reliable than utilizing absolute dose rate. The data is unfolded using comparisons with Monte Carlo simulations to obtain absolute beam temperatures. The data taken on HERMES III show abrupt increases in {beta}{perpendicular} midway through the pulse indicating rapid onset of beam instability.
Menge, P.R.; Maenchen, J.E.; Mazarakis, M.G.; Rosenthal, S.E.
Fast fall-time ion beam in neutron generators
ion beam in neutron generators Q. Ji, J. Kwan, M. Regis, Y.useful in building neutron generators for the application offall-time pulsed neutron generator using an array of 20�20
Ji, Q.
Fast fall-time ion beam in neutron generators
Ion beam with a fast fall time is useful in building neutron generators for the application of detecting hidden, gamma-shielded SNM using differential die-away (DDA) technique. Typically a fall time of less than 1 {micro}s can't be achieved by just turning off the power to the ion source due to the slow decay of plasma density (partly determined by the fall time of the RF power in the circuit). In this paper, we discuss the method of using an array of mini-apertures (instead of one large aperture beam) such that gating the beamlets can be done with low voltage and a small gap. This geometry minimizes the problem of voltage breakdown as well as reducing the time of flight to produce fast gating. We have designed and fabricated an array of 16 apertures (4 x 4) for a beam extraction experiment. Using a gating voltage of 1400 V and a gap distance of 1 mm, the fall time of extracted ion beam pulses is less than 1 {micro}s at various beam energies ranging between 400 eV to 800 eV. Usually merging an array of beamlets suffers the loss of beam brightness, i.e., emittance growth, but that is not an important issue for neutron source applications.
Ji, Q.; Kwan, J.; Regis, M.; Wu, Y.; Wilde, S.B.; Wallig, J.
RAPIDD Gives ALS Users a Faster Path to Beam Time
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RAPIDD Gives ALS Users a Faster RAPIDD Gives ALS Users a Faster Path to Beam Time RAPIDD Gives ALS Users a Faster Path to Beam Time Print Monday, 28 October 2013 08:31 ALS users are invited to check out our web pages detailing our new RAPIDD proposal process. This combined process for Rapid Access Proposals, Industry, and Director's Discretion beam time accommodates users who require limited but rapid access to the ALS. Proposals may be submitted at any time. RAPIDD complements the existing six-month General User Proposal process, which remains the access mechanism of choice for users who require significant beam time for an extended program of research, or for those wanting to perform complex experiments involving setup or reorganization of equipment at a beamline. The ALS structural biology community has been using RAPIDD for a year, with 160 proposals receiving beam time in that period. As of July 2013, RAPIDD access was extended to beamlines 7.3.3 (SAXS/WAXS), 8.3.2 (microtomography) and 11.3.1 (small molecule crystallography) and to users from industrial groups.
While RHIC is filled with beam, bunches are stored for up to several minutes at the injection energy before acceleration starts. In gold operation, the RHIC injection energy is below transition. A bunch length increase, and correspondingly an increase in the longitudinal emittance, can lead to particle loss during transition crossing and rebucketing into the storage buckets. The longitudinal growth of gold beams in RHIC at injection is dominated by intra-beam scattering. Measurements of longitudinal growth times are presented and compared with computations.
Inverse time-of-flight spectrometer for beam plasma research
Science Journals Connector (OSTI)
The paper describes the design and principle of operation of an inverse time-of-flight spectrometer for research in the plasma produced by an electron beam in the forevacuum pressure range (5�20 Pa). In the spectrometer the deflecting plates as well as the drift tube and the primary ion beam measuring system are at high potential with respect to ground. This provides the possibility to measure the mass-charge constitution of the plasma created by a continuous electron beam with a current of up to 300 mA and electron energy of up to 20 keV at forevacuum pressures in the chamber placed at ground potential. Research results on the mass-charge state of the beam plasma are presented and analyzed.
A. V. Tyunkov; K. P. Savkin
Radial electron-beam-breakup transit-time oscillator
A radial electron-beam-breakup transit-time oscillator (RBTO) provides a compact high power microwave generator. The RBTO includes a coaxial vacuum transmission line having an outer conductor and an inner conductor. The inner conductor defines an annular cavity with dimensions effective to support an electromagnetic field in a TEM.sub.00m mode. A radial field emission cathode is formed on the outer conductor for providing an electron beam directed toward the annular cavity electrode. Microwave energy is then extracted from the annular cavity electrode.
Kwan, Thomas J. T. (Los Alamos, NM); Mostrom, Michael A. (Albuquerque, NM)
Expanding Laser Beams: Many times when a laser is used in an optical system,
L- L Project#3 Expanding Laser Beams: Many times when a laser is used in an optical system, there is a requirement for either a larger beam or a beam that has a small divergence (doesn't change size over the length of the experiment). In some casesthe size of the beam becomes critical, for example;when measuring
Yu, Jaehoon
Time domain analysis of a gyrotron traveling wave amplifier with misaligned electron beam
This article develops a time-domain theory to study the beam-wave interaction in gyrotron traveling wave amplifier (gyro-TWA) with a misaligned electron beam. The effects of beam misalignment on the TE{sub 01} mode gyro-TWA operating at the fundamental are discussed. Numerical results show that the effect of misalignment is less obvious when the input power is larger, and the influences of misalignment on the stable gain and the stable time are basically opposite.
Wang, Qiushi, E-mail: firstname.lastname@example.com; Peng, Shuyuan [Institute of Electronics, Chinese Academy of Sciences, P.O. Box 2652, Beijing 100080 (China); University of Chinese Academy of Sciences, Beijing 100039 (China); Luo, Jirun [Institute of Electronics, Chinese Academy of Sciences, P.O. Box 2652, Beijing 100080 (China)
Probing space-time structure of new physics with polarized beams at the ILC
At the International Linear Collider large beam polarization of both the electron and positron beams will enhance the signature of physics due to interactions that are beyond the Standard Model. Here we review our recently obtained results on a general model independent method of determining for an arbitary one-particle inclusive state the space-time structure of such new physics through the beam polarization dependence and angular distribution of the final state particle.
B. Ananthanarayan
Method and apparatus for real time imaging and monitoring of radiotherapy beams
A method and apparatus for real time imaging and monitoring of radiation therapy beams is designed to preferentially distinguish and image low energy radiation from high energy secondary radiation emitted from a target as the result of therapeutic beam deposition. A detector having low sensitivity to high energy photons combined with a collimator designed to dynamically image in the region of the therapeutic beam target is used.
Majewski, Stanislaw (Yorktown, VA); Proffitt, James (Newport News, VA); Macey, Daniel J. (Birmingham, AL); Weisenberger, Andrew G. (Yorktown, VA)
User 'To Do' List as Soon as Beam Time is Assigned | Stanford Synchrotron
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'To Do' List as Soon as Beam Time is Assigned 'To Do' List as Soon as Beam Time is Assigned Safety Review of Scheduled Experiments Identify potential safety issues on proposals and beam time requests. If there are any potential hazards with your samples, materials you are using, or overall set up you may be contacted by the safety office depending on the degree of the hazard indicated. If you want to bring hazardous equipment or substances to SSRL and have not previously indicated this on either your proposal or beam time request (BTR), contact the safety office immediately. Additionally, any changes you may wish to make to your proposal or BTR must be reviewed and approved by the safety office in advance. Late changes that involve potential hazards may not be possible. The experiment information provided by users is used to generate a Safety
Time-dependent simulation of prebunched one and two-beam free electron laser
A numerical simulation in one-dimension is conducted to study the slippage effects on prebunched free electron laser. A technique for the simulation of time dependent free electron lasers (FEL) to model the slippage effects is introduced, and the slowly varying envelope approximation in both z and t is used to illustrate the temporal behaviour in the prebunched FEL. Slippage effect on prebunched two-beam FEL is compared with the one-beam modeling. The evaluation of the radiation pulse energy, thermal and phase distribution, and radiation pulse shape in one-beam and two-beam modeling is studied. It was shown that the performance is considerably undermined when the slippage time is comparable to the pulse duration. However, prebunching reduces the slippage. Prebunching also leads to the radiation pulse with a single smooth spike.
Mirian, N. S., E-mail: firstname.lastname@example.com [School of Particle and Accelerator Physics, Institute for Research in Fundamental Sciences (IPM), Post code 19395-5531 Tehran (Iran, Islamic Republic of); Maraghechi, B. [Department of Physics, Amirkabir University of Technology, Post code 15875-4413 Tehran (Iran, Islamic Republic of)] [Department of Physics, Amirkabir University of Technology, Post code 15875-4413 Tehran (Iran, Islamic Republic of)
Energy and time of flight measurements of REX-ISOLDE stable beams using Si detectors
In this paper we present energy and time spectroscopy measurements for the stable beams of REX-ISOLDE obtained using Si detectors. By using an alpha source as a calibration reference, the absolute energy E of stable beam particles (A/q = 4) was determined in spectroscopy mode in the energy range 1 MeV < E < 8 MeV (0.30 MeV/u < E/A < 1.87 MeV/u). The time of flight of the beam particles (2.18 MeV/u < E/A < 2.27 MeV/u) was determined by installing identical Si detectors in two diagnostic boxes separated by 7.7 m. The results obtained with these two techniques are compared with the values obtained by dipole scans using a bending magnet. The measurements took place between January and February of 2013.
Cantero, E D; Fraser, M A; Lanaia, D; Sosa, A; Voulot, D; Zocca, F
Diamonds as timing detectors for MIP: The HADES proton-beam monitor and start detectors
This paper gives an overview of a recent development of measuring time of flight of minimum-ionizing particles (MIP) with mono-crystalline diamond detectors. The application in the HADES spectrometer as well as test results obtained with proton beams are discussed.
J. Pietraszko; L. Fabbietti; W. Koenig
Diamonds as timing detectors for MIP: The HADES proton-beam monitor and start detectors
This paper gives an overview of a recent development of measuring time of flight of minimum-ionizing particles (MIP) with mono-crystalline diamond detectors. The application in the HADES spectrometer as well as test results obtained with proton beams are discussed.
Solution to the transverse-phase-space time-dependence problem with LAMPF's high-intensity H/sup +/ beam
The 750 keV H/sup +/ beam at LAMPF has a transverse phase-space time-dependent transient during the first 200 ..mu..s of each 750-..mu..s-long macro-pulse. The time dependence is documented in an earlier report. Further studies indicate that the time dependence is due to space-charge neutralization resulting from secondary emission of electrons produced by collisions of the H/sup +/ and H/sub 2//sup +/ beams on the transport walls. One of several possible solutions has been tested and has proven successful in eliminating the time dependence of the beam entering the linac.
Hurd, J.W.
Real-time reflectance-difference spectroscopy of GaAs molecular beam epitaxy homoepitaxial growth
We report on real time-resolved Reflectance-difference (RD) spectroscopy of GaAs(001) grown by molecular beam epitaxy, with a time-resolution of 500�ms per spectrum within the 2.3�4.0 eV photon energy range. Through the analysis of transient RD spectra we demonstrated that RD line shapes are comprised of two components with different physical origins and determined their evolution during growth. Such components were ascribed to the subsurface strain induced by surface reconstruction and to surface stoichiometry. Results reported in this paper render RD spectroscopy as a powerful tool for the study of fundamental processes during the epitaxial growth of zincblende semiconductors.
Lastras-Mart�nez, A., E-mail: firstname.lastname@example.com, E-mail: firstname.lastname@example.com; Ortega-Gallegos, J.; Guevara-Mac�as, L. E.; Nu�ez-Olvera, O.; Balderas-Navarro, R. E.; Lastras-Mart�nez, L. F. [Instituto de Investigaci�n en Comunicaci�n Optica, Universidad Aut�noma de San Luis Potos�, Alvaro Obreg�n 64, San Luis Potos�, SLP 78000 (Mexico); Lastras-Monta�o, L. A. [IBM T. J. Watson Research Center, Yorktown Heights, New York 10598 (United States); Lastras-Monta�o, M. A. [Department of Electrical and Computer Engineering, University of California, Santa Barbara, Santa Barbara, California 93106 (United States)
Ion Beams - Radiation Effects Facility / Cyclotron Institute...
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Ion Beams Available Beams Beam Change Times Measurements Useful Graphs Various ion beams have been developed specifically for the Radiation Effects Facility. These beams...
Isobar separation by time-of-flight mass spectrometry for low-energy radioactive ion beam facilities
Science Journals Connector (OSTI)
A multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS) system for low-energy radioactive ion beam facilities has been developed, which can be used for (i) isobar separation and (ii) direct mass measurements of very short-lived nuclei with half-lives of about 1�ms or longer, and (iii) for identification and diagnosis of the ion beam by mass spectrometry. The system has been designed and simulated, and individual subsystems have been built and characterized experimentally. An injection trap for cooling and bunching of the ion beam has been developed, and cooling times of less than one millisecond have been achieved. The performance of the MR-TOF-MS was characterized using the isobaric doublet of carbon monoxide and nitrogen molecular ions. A mass resolving power of 105 (FWHM) has been obtained even with an uncooled ion population. The separator capabilities of the MR-TOF-MS have been demonstrated by removing either carbon monoxide or nitrogen ions from the beam in a Bradbury-Nielsen Gate after a flight time of 320�?s. The separation power achieved is thus at least 7000 (FWHM) and increases for longer time-of-flight. An energy buncher stage has been designed that compresses the energy spread of the beam after the separation and facilitates efficient injection of the selected ions into an accumulation trap prior to transfer of the ions to experiments downstream of the MR-TOF-MS.
Wolfgang R. Pla�; Timo Dickel; Ulrich Czok; Hans Geissel; Martin Petrick; Katrin Reinheimer; Christoph Scheidenberger; Mikhail I.Yavor
A measurement of the energy and timing resolution of GlueX Forward Calorimeter using an electron beam
The performance of the GlueX Forward Calorimeter was studied using a small version of the detector and a variable energy electron beam derived from the Hall B tagger at Jefferson Lab. For electron energies from 110 MeV to 260 MeV, which are near the lower-limits of the design sensitivity, the fractional energy resolution was measured to range from 20% to 14%, which meets the design goals. The use of custom 250 MHz flash ADCs for readout allowed precise measurements of signal arrival times. The detector achieved timing resolutions of 0.38 ns for a single 100 mV pulse, which will allow timing discrimination of photon beam bunches and out-of-time background during the operation of the GlueX detector.
Kei Moriya; John P. Leckey; Matthew R. Shepherd; Kevin Bauer; Daniel Bennett; John Frye; Juan Gonzalez; Scott J. Henderson; David Lawrence; Ryan Mitchell; Elton S. Smith; Paul Smith; Alexander Somov; Hovanes Egiyan
Modified Sagnac experiment for measuring travel-time difference between counter-propagating light beams in a uniformly moving fiber
A fiber optic conveyor has been developed for investigating the travel-time difference between two counter-propagating light beams in uniformly moving fiber. Our finding is that there is a travel-time difference Deltat=2vDeltal/c^2 in a fiber segment of length Deltal moving with the source and detector at a speed v, whether the segment is moving uniformly or circularly.
Ruyong Wang; Yi Zheng; Aiping Yao; Dean Langley
Measurements - Ion Beams - Radiation Effects Facility / Cyclotron...
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Ion Beams Available Beams Beam Change Times Measurements Useful Graphs Measurements The beam uniformity and flux are determined using an array of five detectors. Each...
Impact of electron collision mixing on the delay times of an electron beam excited atomic xenon laser
The atomic xenon (5d {r arrow} 6p) infrared laser has been experimentally and theoretically investigated using a short pulse (30 ns) high power (1-10 MW/cm{sup 3}) coaxial electron beam excitation source. In most cases, laser oscillation is not observed during the e-beam current pulse. Laser pulses of 100's of ns duration are subsequently obtained, however, with oscillation beginning 60-800 ns after the current pulse terminates. Results from a computer model for the xenon laser reproduce the experimental values, and show that oscillation begins when the fractional electron density decays below a critical value of {approx} 0.2-0.8 {times} 10{sup 6}. These results lend credance to the proposal that electron collision mixing of the laser levels limits the maximum value of specific power deposition which may be used to efficiently excite the atomic xenon laser on a quasi-CW basis.
Peters, P.J. (Dept. of Applied Physics, Univ. of Twente, 7500 AE Enshede (NL)); Lan, Y.F. (Inst. of Electronics, Beijing (CN)); Ohwa, M. (Dept. of Electrical Engineering, Keio Univ., Yokahama (JP)); Kushner, M.J. (Dept. of Electrical and Computer Engineering, Univ. of Illinois, Urbana, IL (US))
Electrostatic bottle for long-time storage of fast ion beams
Science Journals Connector (OSTI)
A technique for storage of fast-ion beams (keV) using only electrostatic fields is presented. The fast-ion trap is designed like an optical resonator, whose electrode configuration allows for a very large field-free region, easy access into the trap by various probes, a simple ion loading technique, and a broad acceptance range for the initial kinetic energies of the ions. Such a fast-ion storage device opens up many experimental possibilities, a few of which are presented.
D. Zajfman; O. Heber; L. Vejby-Christensen; I. Ben-Itzhak; M. Rappaport; R. Fishman; M. Dahan
In high energy storage-ring colliders, the nonlinear effect arising from beam-beam interactions is a major source that leads to the emittance growth, the reduction of beam life time, and limits the collider luminosity. In this paper, two models of beam-beam interactions are introduced, which are weak-strong and strong-strong beam-beam interactions. In addition, space-charge model is introduced.
Kim, Hyung Jin; /Fermilab
Real time two?dimensional temperature imaging for guidance and monitoring of high?intensity focused ultrasound beams.
Science Journals Connector (OSTI)
We have recently introduced a fully real time 2?D temperature imaging system using diagnostic ultrasound. A SonixRP is used to collect beamformed M2D mode data with frame rates in the 200�400 fps during the application of pulsed high?intensity focused ultrasound (pHIFU). M2D mode is a modification on the SonixRP allowing for maximizing the number of scanlines per frame for a specified frame rate. This allows for capturing the full range of tissue motions during the application of the pHIFU beams including native motions due to breathing and pulsations radiation forces due to pHIFU and temperature?induced strains. In this paper we demonstrate the use of this image?guidance mode in the control of the pHIFU exposure in real time with millisecond temporal resolution. Results from heating and lesion formation experiments in the hindlimb of nude mice in vivo will be presented. Temperature imaging results during the application of subtherapeutic pHIFU beams before therapeutic pHIFU lesion formation will demonstrate the advantages of this approach in the guidance and dose estimation. In addition temperature imaging of subtherapeutic pHIFU after lesion formation allows for the measurement of changes in tissue properties that may be used as indicators of irreversible tissue damage.
Dalong Liu; John R. Ballard; Alyona Haritonova; Jing Jiang; John C. Bischof; Emad S. Ebbini
Multimodal registration of three-dimensional maxillodental cone beam CT and photogrammetry data over time
change over time. Dentomaxillofacial Radiology (2012) 0, 19. doi: 10.1259/dmfr/22027087 Keywords: three) scanner] may suffice to solve some clinical dental issues, in more general cases, dentists must email@example.com Received 2 January 2012; revised 12 April 2012; accepted 20 April 2012 Dentomaxillofacial Radiology (2012
Alberta, University of
Fundamental electron-precursor-solid interactions derived from time dependent electron beam induced deposition simulations and experiments
Unknown parameters critical to understanding the electron-precursor substrate interactions during electron beam induced deposition (EBID) have long limited our ability to fully control this nanoscale, directed assembly method. We report here values for the fundamental interaction parameters of D, the precursor surface diffusion coefficient, delta, the sticking probability and tau, the mean surface residence time which are critical parameters for understanding the assembly of EBID deposits. Values of D=6.4um2s-1, delta=0.0250 and tau=3.2ms were determined for a commonly used precursor molecule tungsten hexacarbonyl W(CO)6. Space and time predictions of the adsorbed precursor coverage C(r,t) were solved by an explicit finite differencing numerical scheme. Evolving nanopillar surface morphology was derived from solutions of C(r,t) considering electron induced dissociation as the critical depletion term. This made it possible to infer the space and time dependent precursor coverage both on, and around nanopillar structures to better understand local precursor dynamics during mass transport limited (MTL) and reaction rate limited (RRL) EBID.
Fowlkes, Jason Davidson [ORNL; Rack, Philip D [ORNL
Useful Graphs and Charts - Ion Beams - Radiation Effects Facility...
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Ion Beams Available Beams Beam Change Times Measurements Useful Graphs Useful Graphs and Charts LET vs. Range in Si Graphs: 15 MeVu Beams 24.8 MeVu Beams 40 MeVu Beams...
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Beam Status Beam History Print Beamline History Request Form To request a beam current histograph from the ALS storage ring beam histograph database, select the year, month, and...
Neutron Scattering Science User Office, email@example.com or (865) 574-4600. Proposals for beam time at Oak Ridge National Laboratory's High Flux Isotope Reactor (HFIR)
Neutron Scattering Science User Office, email@example.com or (865) 574-4600. Proposals for beam Wildgruber, email@example.com. VISION CallforProposals neutrons.ornl.gov Neutron Scattering Science - Oak time at Oak Ridge National Laboratory's High Flux Isotope Reactor (HFIR) and Spallation Neutron Source
Pennycook, Steve
Magnetically operated beam dump for dumping high power beams in a neutral beamline
It is an object of this invention to provide a beam dump system for a neutral beam generator which lowers the time-averaged power density of the beam dump impingement surface. Another object of this invention is to provide a beam dump system for a neutral particle beam based on reionization and subsequent magnetic beam position modulation of the beam onto a beam dump surface to lower the time-averaged power density of the beam dump ion impingement surface.
Dagenhart, W.K.
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Beam History Print Beamline History Request Form To request a beam current histograph from the ALS storage ring beam histograph database, select the year, month, and day, then...
Science Journals Connector (OSTI)
The possibility of splitting a surface muon beam into three separate components using an ... and could be very effectively used to provide muons to time differential ?SR experiments.
J. L. Beveridge
REVIEW ARTICLE Taming molecular beams
REVIEW ARTICLE Taming molecular beams The motion of neutral molecules in a beam can be manipulated time-varying fields can be used to decelerate or accelerate beams of molecules to any desired velocity. We review the possibilities that this molecular-beam technology offers, ranging from ultrahigh
Loss, Daniel
Noninterceptive beam diagnostics
The need for accurate real-time diagnostics is critical for high-power particle beams. This paper describes the present level of development of noninterceptive devices for these beams. Discussion will be related to diagnostic measurements as they occur along the beamline, from ion-source performance through presentation to an RFQ and measures of the RFQ output, using the cw beam at Los Alamos as a guide. 23 refs.
Chamberlin, D.D.
Light beam frequency comb generator
A light beam frequency comb generator uses an acousto-optic modulator to generate a plurality of light beams with frequencies which are uniformly separated and possess common noise and drift characteristics. A well collimated monochromatic input light beam is passed through this modulator to produce a set of both frequency shifted and unshifted optical beams. An optical system directs one or more frequency shifted beams along a path which is parallel to the path of the input light beam such that the frequency shifted beams are made incident on the modulator proximate to but separated from the point of incidence of the input light beam. After the beam is thus returned to and passed through the modulator repeatedly, a plurality of mutually parallel beams are generated which are frequency-shifted different numbers of times and possess common noise and drift characteristics.
Priatko, Gordon J. (Cupertino, CA); Kaskey, Jeffrey A. (Livermore, CA)
Simulation of beam-beam effects in tevatron
The Fermilab accelerator complex is in the middle of an upgrade plan Fermilab III. In the last phase of this upgrade the luminosity of the Tevatron will increase by at least one order of magnitude. In order to keep the number of interactions per crossing manageable for experiments, the number of bunches will be increased from 6 {times} 6 to 36 {times} 36 and finally to {approximately}100 {times} 100 bunches. The beam dynamics of the Tevatron has been studied from Beam-Beam effect point of view in a ``Strong-Weak`` representation with a single particle being tracked in presence of other beam. This paper describes the beam-beam effect in 6 {times} 6 operation of Tevatron.
Mishra, C.S.; Assadi, S. [Fermi National Accelerator Lab., Batavia, IL (United States); Talman, R. [Cornell Univ., Ithaca, NY (United States)
The Stanford Linear Collider (SLC){sup 1,2} accelerates single bunches of electrons and positrons to 47 GeV per beam and collides them with small beam sizes and at high currents. The beam emittances and intensities required for present operation have significantly extended traditional beam quality limits. The electron source produces over 10{sup 11} e{sup {minus}} in each of two bunches. The damping rings provide coupled invariant emittances of 1.8 {times} 10{sup {minus}5} r-m at 4.5 {times} 10{sup 10} particles. The 50 GeV linac has successfully accelerated over 3 {times} 10{sup 10} particles with design invariant emittances of 3 {times} 10{sup {minus}5} r-m. The collider arcs are now sufficiently decoupled and matched in betatron space, so that the final focus can be chromatically corrected, routinely producing spot sizes ({sigma}{sub x}, {sigma}{sub y}) of 2.5 {mu}m at the interaction point. Spot sizes below 2 {mu}m have been made during tests. Instrumentation and feedback systems are well advanced, providing continuous beam monitoring and considerable pulse-by-pulse control. The luminosity reliability is about 60%. Overviews of the recent accelerator physics achievements used to obtain these parameters and the present limiting phenomena are described for each accelerator subsystem.
Seeman, J.T.
Electron beam ion sources (EBISs) are ion sources that work based on the principle of electron impact ionization, allowing the production of very highly charged ions. The ions produced can be extracted as a DC ion beam as well as ion pulses of different time structures. In comparison to most of the other known ion sources, EBISs feature ion beams with very good beam emittances and a low energy spread. Furthermore, EBISs are excellent sources of photons (X-rays, ultraviolet, extreme ultraviolet, visible light) from highly charged ions. This chapter gives an overview of EBIS physics, the principle of operation, and the known technical solutions. Using examples, the performance of EBISs as well as their applications in various fields of basic research, technology and medicine are discussed.
Zschornacka, G; Thorn, A
Are Cluster Ion Analysis Beams Good Choices for Hydrogen Depth...
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Cluster Ion Analysis Beams Good Choices for Hydrogen Depth Profiling Using Time-of-Flight Secondary Ion Mass Spectrometry? Are Cluster Ion Analysis Beams Good Choices for Hydrogen...
Accelerators, Beams And Physical Review Special Topics - Accelerators And Beams
Accelerator science and technology have evolved as accelerators became larger and important to a broad range of science. Physical Review Special Topics - Accelerators and Beams was established to serve the accelerator community as a timely, widely circulated, international journal covering the full breadth of accelerators and beams. The history of the journal and the innovations associated with it are reviewed.
Siemann, R.H.; /SLAC
Science Journals Connector (OSTI)
Intense nonrelativistic light-ion beams generated in magnetically insulated diodes can reach total beam currents large enough to confine charged fusion products within pinch channels which are formed by these beams if they are projected onto thermonuclear material. Furthermore, since the required beam currents are still below the critical Alfv�n current, these pinch channels are magnetohydrodynamically stable. However, because the time these beams last is very short and of the order of 10 nsec, the thermonuclear target must have a density at least as large as solid-state density to satisfy the Lawson criterion. This large target density makes it necessary that the beam be focused down to a radius less than ? 10-2 cm, to balance the plasma pressure against the magnetic pressure. To make this focusing possible a new kind of a low-emittance intense ion source is proposed. It consists of pointlike pulsed dense plasma positioned in the field-free space behind a meshlike anode. The focusing itself can be done in three steps, first by sufficiently good ion optics, second by wall focusing, and third by radiation cooling. This inertial-confinement fusion concept avoids the problems of reaching this goal through highdensity target compression by ablative implosion.
F. Winterberg
A large liquid argon time projection chamber for long-baseline, off-axis neutrino oscillation physics with the NuMI beam
Results from neutrino oscillation experiments in the last ten years have revolutionized the field of neutrino physics. While the overall oscillation picture for three neutrinos is now well established and precision measurements of the oscillation parameters are underway, crucial issues remain. In particular, the hierarchy of the neutrino masses, the structure of the neutrino mixing matrix, and, above all, CP violation in the neutrino sector are the primary experimental challenges in upcoming years. A program that utilizes the newly commissioned NuMI neutrino beamline, and its planned upgrades, together with a high-performance, large-mass detector will be in an excellent position to provide decisive answers to these key neutrino physics questions. A Liquid Argon time projection chamber (LArTPC) [2], which combines fine-grained tracking, total absorption calorimetry, and scalability, is well matched for this physics program. The few-millimeter-scale spatial granularity of a LArTPC combined with dE/dx measurements make it a powerful detector for neutrino oscillation physics. Scans of simulated event samples, both directed and blind, have shown that electron identification in {nu}{sub e} charged current interactions can be maintained at an efficiency of 80%. Backgrounds for {nu}{sub e} appearance searches from neutral current events with a {pi}{sup 0} are reduced well below the {approx} 0.5-1.0% {nu}{sub e} contamination of the {nu}{sub {mu}} beam [3]. While the ICARUS collaboration has pioneered this technology and shown its feasibility with successful operation of the T600 (600-ton) LArTPC [4], a detector for off-axis, long-baseline neutrino physics must be many times more massive to compensate for the low event rates. We have a baseline concept [5] based on the ICARUS wire plane structure and commercial methods of argon purification and housed in an industrial liquefied-natural-gas tank. Fifteen to fifty kton liquid argon capacity tanks have been considered. A very preliminary cost estimate for a 50-kton detector is $100M (unloaded) [6]. Continuing R&D will emphasize those issues pertaining to implementation of this very large scale liquid argon detector concept. Key hardware issues are achievement and maintenance of argon purity in the environment of an industrial tank, the assembly of very large electrode planes, and the signal quality obtained from readout electrodes with very long wires. Key data processing issues include an initial focus on rejection of cosmic rays for a surface experiment. Efforts are underway at Fermilab and a small number of universities in the US and Canada to address these issues with the goal of embarking on the construction of industrial-scale prototypes within one year. One such prototype could be deployed in the MiniBooNE beamline or in the NuMI surface building where neutrino interactions could be observed. These efforts are complementary to efforts around the world that include US participation, such as the construction of a LArTPC for the 2-km detector location at T2K [7]. The 2005 APS neutrino study [1] recommendations recognize that ''The development of new technologies will be essential for further advances in neutrino physics''. In a recent talk to EPP2010, Fermilab director P. Oddone, discussing the Fermilab program, states on his slides: ''We want to start a long term R&D program towards massive totally active liquid Argon detectors for extensions of NOvA''. [8]. As such, we are poised to enlarge our R&D efforts to realize the promise of a large liquid argon detector for neutrino physics.
Finley, D.; Jensen, D.; Jostlein, H.; Marchionni, A.; Pordes, S.; Rapidis, P.A.; /Fermilab; Bromberg, C.; /Michigan State U.; Lu, C.; McDonald, T.; /Princeton U.; Gallagher,; Mann, A.; Schneps, J.; /Tufts U.; Cline, D.; Sergiampietri, F.; Wang, H.; /UCLA; Curioni, A.; Fleming, B.T.; /Yale U.; Menary, S.; /York U., Canada
Autogenerator of beams of charged particles
An autogenerating apparatus provides secondary intense relativistic current beam pulses in response to an injected beam pulse. One or more electromagnetic energy storage devices are provided in conjunction with gaps along a beam propagation path for the injected beam pulse. For injected beam pulses which are no longer than double the transit time of electromagnetic waves within the storage devices (which may be resonant cavities), distinct secondary beam pulses are generated by each of the energy storage devices. The beam propagation path, together with the one or more gaps provided therein, operates as a pulse forming transmission line cavity, in which the separate cavities associated with the gaps provide delays for electromagnetic waves generated at the gaps. After doubly traversing the cavity, the electromagnetic waves cause the gap to generate the secondary beam pulses, which are thus delayed by a time interval equal to the double transit time for the induced wave within the cavity.
Adler, R.J.; Mazarakis, M.G.; Miller, R.M.; Shope, S.L.; Smith, D.L.
Autogenerator of beams of charged particles
An autogenerating apparatus provides secondary intense relativistic current beam pulses in response to an injected beam pulse. One or more electromagnetic energy storage devices are provided in conjunction with gaps along a beam propagation path for the injected beam pulse. For injected beam pulses which are no longer than double the transit time of electromagnetic waves within the storage devices (which may be resonant cavities), distinct secondary beam pulses are generated by each of the energy storage devices. The beam propagation path, together with the one or more gaps provided therein, operates as a pulse forming transmission line cavity, in which the separate cavities associated with the gaps provide delays for electromagnetic waves generated at the gaps. After doubly traversing the cavity, the electromagnetic waves cause the gap to generate the secondary beam pulses, which are thus delayed by a time interval equal to the double transit time for the induced wave within the cavity.
Adler, Richard J. (Albuquerque, NM); Mazarakis, Michael G. (Albuquerque, NM); Miller, Robert B. (Albuquerque, NM); Shope, Steven L. (Albuquerque, NM); Smith, David L. (Albuquerque, NM)
Time growth rate and field profiles of hybrid modes excited by a relativistic elliptical electron beam in an elliptical metallic waveguide with dielectric rod
The dispersion relation of guided electromagnetic waves propagating in an elliptical metallic waveguide with a dielectric rod driven by relativistic elliptical electron beam (REEB) is investigated. The electric field profiles and the growth rates of the waves are numerically calculated by using Mathieu functions. The effects of relative permittivity constant of dielectric rod, accelerating voltage, and current density of REEB on the growth rate are presented.
Jazi, B.; Rahmani, Z.; Abdoli-Arani, A. [Faculty of Physics, Department of Laser and Photonics, University of Kashan, Kashan (Iran, Islamic Republic of); Heidari-Semiromi, E. [Faculty of Physics, Department of Condense Matter, University of Kashan, Kashan (Iran, Islamic Republic of)
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One: One: Single-Bunch Comparative Study of Three Algorithms Peter Tenenbaum LCC-Note-0013 17-February-1999 Abstract We describe the results of a series of simulation studies of beam-based alignment of the NLC main linacs using the program LIAR. Three algorithms for alignment of quadrupoles and girders are consid- ered: the algorithm used in the ZDR, the ZDR algorithm combined with a post-alignment MICADO operation, and an algorithm which requires no steering dipoles but requires twice as many alignment segments per linac as the ZDR algorithm. The third algorithm appears to be the most robust, based on convergence time, required quad mover step sizes, and variation in extracted beam emittance as a function of BNS profile. We also study the effect of structure BPM resolution and ATL misalignments during the alignment process. 1 Introduction Beam-based alignment and steering of the
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BEAM LINE BEAM LINE 45 W ILHELM ROENTGEN'S INITIAL DISCOVERY of X-radiation in 1895 led immediately to practical applications in medicine. Over the next few decades X rays proved to be an invaluable tool for the investigation of the micro-world of the atom and the development of the quantum theory of matter. Almost a century later, telescopes designed to detect X-radiation are indispensable for understanding the structure and evolution of the macro-world of stars, galaxies, and the Universe as a whole. The X-Ray Universe by WALLACE H. TUCKER X-ray images of the Universe are strikingly different from the usual visible-light images. 46 SUMMER 1995 did not think: I investigated." Undeterred by NASA's rejection of a proposal to search for cosmic X-radiation, Giacconi persuaded the
A pencil beam algorithm for helium ion beam therapy
Purpose: To develop a flexible pencil beam algorithm for helium ion beam therapy. Dose distributions were calculated using the newly developed pencil beam algorithm and validated using Monte Carlo (MC) methods. Methods: The algorithm was based on the established theory of fluence weighted elemental pencil beam (PB) kernels. Using a new real-time splitting approach, a minimization routine selects the optimal shape for each sub-beam. Dose depositions along the beam path were determined using a look-up table (LUT). Data for LUT generation were derived from MC simulations in water using GATE 6.1. For materials other than water, dose depositions were calculated by the algorithm using water-equivalent depth scaling. Lateral beam spreading caused by multiple scattering has been accounted for by implementing a non-local scattering formula developed by Gottschalk. A new nuclear correction was modelled using a Voigt function and implemented by a LUT approach. Validation simulations have been performed using a phantom filled with homogeneous materials or heterogeneous slabs of up to 3 cm. The beams were incident perpendicular to the phantoms surface with initial particle energies ranging from 50 to 250 MeV/A with a total number of 10{sup 7} ions per beam. For comparison a special evaluation software was developed calculating the gamma indices for dose distributions. Results: In homogeneous phantoms, maximum range deviations between PB and MC of less than 1.1% and differences in the width of the distal energy falloff of the Bragg-Peak from 80% to 20% of less than 0.1 mm were found. Heterogeneous phantoms using layered slabs satisfied a {gamma}-index criterion of 2%/2mm of the local value except for some single voxels. For more complex phantoms using laterally arranged bone-air slabs, the {gamma}-index criterion was exceeded in some areas giving a maximum {gamma}-index of 1.75 and 4.9% of the voxels showed {gamma}-index values larger than one. The calculation precision of the presented algorithm was considered to be sufficient for clinical practice. Although only data for helium beams was presented, the performance of the pencil beam algorithm for proton beams was comparable. Conclusions: The pencil beam algorithm developed for helium ions presents a suitable tool for dose calculations. Its calculation speed was evaluated to be similar to other published pencil beam algorithms. The flexible design allows easy customization of measured depth-dose distributions and use of varying beam profiles, thus making it a promising candidate for integration into future treatment planning systems. Current work in progress deals with RBE effects of helium ions to complete the model.
Fuchs, Hermann; Stroebele, Julia; Schreiner, Thomas; Hirtl, Albert; Georg, Dietmar [Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, 1090 Vienna (Austria); Department of Radiation Oncology, Medical University of Vienna/AKH Vienna, 1090 Vienna (Austria) and Comprehensive Cancer Center, Medical University of Vienna/AKH Vienna, 1090 Vienna (Austria); Department of Radiation Oncology, Medical University of Vienna/AKH Vienna (Austria) and Comprehensive Cancer Center, Medical University of Vienna/AKH Vienna, 1090 Vienna (Austria); PEG MedAustron, 2700 Wiener Neustadt (Austria); Department of Nuclear Medicine, Medical University of Vienna, 1090 Vienna (Austria); Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, 1090 Vienna (Austria); Department of Radiation Oncology, Medical University of Vienna/AKH Vienna, 1090 Vienna (Austria) and Comprehensive Cancer Center, Medical University of Vienna/AKH Vienna, 1090 Vienna (Austria)
Carbon Fiber Damage in Accelerator Beam
Carbon fibers are commonly used as moving targets in Beam Wire Scanners. Because of their thermomechanical properties they are very resistant to particle beams. Their strength deteriorates with time due to radiation damage and low-cycle thermal fatigue. In case of high intensity beams this process can accelerate and in extreme cases the fiber is damaged during a single scan. In this work a model describing the fiber temperature, thermionic emission and sublimation is discussed. Results are compared with fiber damage test performed on SPS beam in November 2008. In conclusions the limits of Wire Scanner operation on high intensity beams are drawn.
Sapinski, M; Guerrero, A; Koopman, J; M�tral, E
Nanopatterning of metal-coated silicon surfaces via ion beam irradiation: Real time x-ray studies reveal the effect of silicide bonding
We investigated the effect of silicide formation on ion-induced nanopatterning of silicon with various ultrathin metal coatings. Silicon substrates coated with 10 nm Ni, Fe, and Cu were irradiated with 200 eV argon ions at normal incidence. Real time grazing incidence small angle x-ray scattering (GISAXS) and x-ray fluorescence (XRF) were performed during the irradiation process and real time measurements revealed threshold conditions for nanopatterning of silicon at normal incidence irradiation. Three main stages of the nanopatterning process were identified. The real time GISAXS intensity of the correlated peaks in conjunction with XRF revealed that the nanostructures remain for a time period after the removal of the all the metal atoms from the sample depending on the binding energy of the metal silicides formed. Ex-situ XPS confirmed the removal of all metal impurities. In-situ XPS during the irradiation of Ni, Fe, and Cu coated silicon substrates at normal incidence demonstrated phase separation and the formation of different silicide phases that occur upon metal-silicon mixing. Silicide formation leads to nanostructure formation due the preferential erosion of the non-silicide regions and the weakening of the ion induced mass redistribution.
El-Atwani, Osman [School of Materials Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 (United States); Gonderman, Sean; Suslova, Anastassiya; Fowler, Justin; El-Atwani, Mohamad [School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); DeMasi, Alexander; Ludwig, Karl [Physics Department, Boston University, Boston, Massachusetts 02215 (United States); Paul Allain, Jean [School of Materials Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 (United States); School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States)
Summary of the LARP Mini-Workshop on Beam-Beam Compensation 2007
The LARP Mini-Workshop on Beam-Beam Compensation 2007 was held at SLAC, 2-4 July 2007. It was attended by 33 participants from 10 institutions in Asia, Europe, and America. 26 presentations were given, while more than one third of the time was allocated to discussions. The workshop web site is Ref. [1]. The workshop's main focus was on long-range and head-on beam-beam compensation, with a view towards application in the LHC. Other topics included the beam-beam performance of previous, existing and future circular colliders; beam-beam simulations; new operating modes, theory, and unexplained phenomena. This summary is also published as Ref. [2].
Fischer, Wolfram; /Brookhaven; Bruning, Oliver S.; Koutchouk, J.P.; Zimmermann, F.; /CERN; Sen, T.; Shiltsev, V.; /Fermilab; Ohmi, K.; /KEK, Tsukuba; Furman, M.; /LBL, Berkeley; Cai, Y.; Chao, A.; /SLAC
6.21 Improving Neutron Beams for Cancer Treatment
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1 612011 6.21 Improving Neutron Beams for Cancer Treatment Beams of neutrons long have been used in scientific experiments, but recently, for the first time, a novel type of...
The Radiation Security System (RSS) at the Los Alamos Neutron Science Center (LANSCE) provides personnel protection from prompt radiation due to accelerated beam. Active instrumentation, such as the Beam Current Limiter, is a component of the RSS. The current limiter is designed to limit the average current in a beam line below a specific level, thus minimizing the maximum current available for a beam spill accident. The beam current limiter is a self-contained, electrically isolated toroidal beam transformer which continuously monitors beam current. It is designed as fail-safe instrumentation. The design philosophy, hardware design, operation, and limitations of the device are described.
Gallegos, F.R.
Relativistic atomic beam spectroscopy II
We are requesting support for a postdoctoral person to participate in H{sup -} studies at Los Alamos. In addition, we are requesting funding for a state-of-the-art YAG laser system that would allow us to obtain data at three times our present rate with improved beam quality.
Electron beam diagnostic for profiling high power beams
A system for characterizing high power electron beams at power levels of 10 kW and above is described. This system is comprised of a slit disk assembly having a multitude of radial slits, a conducting disk with the same number of radial slits located below the slit disk assembly, a Faraday cup assembly located below the conducting disk, and a start-stop target located proximate the slit disk assembly. In order to keep the system from over-heating during use, a heat sink is placed in close proximity to the components discussed above, and an active cooling system, using water, for example, can be integrated into the heat sink. During use, the high power beam is initially directed onto a start-stop target and after reaching its full power is translated around the slit disk assembly, wherein the beam enters the radial slits and the conducting disk radial slits and is detected at the Faraday cup assembly. A trigger probe assembly can also be integrated into the system in order to aid in the determination of the proper orientation of the beam during reconstruction. After passing over each of the slits, the beam is then rapidly translated back to the start-stop target to minimize the amount of time that the high power beam comes in contact with the slit disk assembly. The data obtained by the system is then transferred into a computer system, where a computer tomography algorithm is used to reconstruct the power density distribution of the beam.
Elmer, John W. (Danville, CA); Palmer, Todd A. (Livermore, CA); Teruya, Alan T. (Livermore, CA)
AFRD - Center for Beam Physics
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Center for Beam Physics Center for Beam Physics Home Organization Outreach and Diversity Highlights Safety Links Intramural Group photo of our staff CBP staff, May 2011 CBP in the News: Read about an innovation in super-precise timing and synchronization; and a look toward the next generation of electron guns with responsiveness and brightness needed by future free-electron lasers such as those in the Next Generation Light Source initiative. Who We Are and What We Do The Center for Beam Physics (CBP) is a resource for meeting the challenges of accelerator science, and a source of many innovative concepts, within the Accelerator and Fusion Research Division. We have core expertise in accelerator physics and theory, accelerator modeling using high performance computing, and instrumentation,
BEAMS3D Neutral Beam Injection Model
With the advent of applied 3D fi elds in Tokamaks and modern high performance stellarators, a need has arisen to address non-axisymmetric effects on neutral beam heating and fueling. We report on the development of a fully 3D neutral beam injection (NBI) model, BEAMS3D, which addresses this need by coupling 3D equilibria to a guiding center code capable of modeling neutral and charged particle trajectories across the separatrix and into the plasma core. Ionization, neutralization, charge-exchange, viscous velocity reduction, and pitch angle scattering are modeled with the ADAS atomic physics database [1]. Benchmark calculations are presented to validate the collisionless particle orbits, neutral beam injection model, frictional drag, and pitch angle scattering effects. A calculation of neutral beam heating in the NCSX device is performed, highlighting the capability of the code to handle 3D magnetic fields.
Lazerson, Samuel
A TALE OF TWO BEAMS: GAUSSIAN BEAMS AND BESSEL BEAMS ROBERT L. NOWACK Abstract. An overview is given of two types of focused beams, Gaussian beams and Bessel beams. First I describe some of the basic properties of Gaussian beams in homogeneous media which stay collimated over a certain distance range after
Nowack, Robert L.
LBNL-45363, CBP Note 333 BEAM-BEAM SIMULATIONS FOR SEPARATED BEAMS
LBNL-45363, CBP Note 333 BEAM-BEAM SIMULATIONS FOR SEPARATED BEAMS Miguel A. Furman, Center for Beam Physics, LBNL, Berkeley, CA 94720 Abstract We present beam-beam simulation results from a strong- strong gaussian code for separated beams for the LHC and RHIC. The frequency spectrum produced
Furman, Miguel
LBNL-46223, CBP Note 350 BEAM-BEAM SIMULATIONS FOR SEPARATED BEAMS IN THE LHC
LBNL-46223, CBP Note 350 BEAM-BEAM SIMULATIONS FOR SEPARATED BEAMS IN THE LHC M. A. Furman, W. C. Turner, Center for Beam Physics, LBNL, Berkeley, CA 94720, USA Abstract We present beam-beam simulation results from a strong- strong gaussian code for separated beams for the LHC. We focus on the possible
Furman, Miguel
BEAMS: Curiosity | Jefferson Lab
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BEAMS: Curiosity January 9, 2013 BEAMS, Becoming Excited About Math and Science, is one of our education programs. In particular, it is the only one in which I participate with...
Ultrasonic imaging with limited-diffraction beams
Limited-diffraction beams are a class of waves that may be localized in space and time. Theoretically, these beams are propagation invariant and can propagate to an infinite distance without spreading. In practice, when these beams are produced with wave sources of a finite aperture and energy, they have a very large depth of field, meaning that they can keep a small beam width over a large distance. Because of this property, limited-diffraction beams may have applications in various areas such as medical imaging and tissue characterization. In this paper, fundamentals of limited-diffraction beams are reviewed and the studies of these beams are put into a unified theoretical framework. Theory of limited-diffraction beams is further developed. New limited-diffraction solutions to Klein-Gordon Equation and Schrodinger Equation, as well as limited-diffraction solutions to these equations in confined spaces are obtained. The relationship between the transformation that converts any solutions to an (-1)-dimensional wave equation to limited-diffraction solutions of an -dimensional equation and the Lorentz transformation is clarified and extended. The transformation is also applied to the Klein-Gordon Equation. In addition, applications of limited-diffraction beams are summarized.
Jian-yu Lu
This report describes beam director elements for an experiment at the Advanced Test Accelerator. The elements described include a vernier magnet for beam aiming, an achromat magnet, and an isolation system for the beam interface. These components are built at small scale for concept testing. (JDH)
Lee, E.P.; Younger, F.C.; Cruz, G.E.; Nolting, E.
Inexpensive dual beam turbidimeter
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...Articles Articles Inexpensive dual beam turbidimeter Cathie Lubell Thomas Barry Edward Brody Gregory Hearn This dual beam turbidimeter...74D728B5-2B21-11D7-8648000102C1865D Inexpensive dual beam turbidimeter Lubell Cathie Author Barry Thomas Author Brody Edward Author Hearn...
Cathie Lubell; Thomas Barry; Edward Brody; Gregory Hearn
A Note on the Sagnac Effect for Matter Beams
We study the Sagnac effect for matter beams, in order to estimate the kinematic corrections to the basic formula, deriving from the position and the extension of the interferometer, and discuss the analogy with the Aharonov-Bohm effect. We show that the formula for the Sagnac time delay is the same for matter and light beams in arbitrary stationary space-times, provided that a suitable condition on the speed of the beams is fulfilled. Hence, the same results obtained for light beams apply to matter beams.
Matteo Luca Ruggiero; Angelo Tartaglia
A Note on the Sagnac Effect for Matter Beams
We study the Sagnac effect for matter beams, in order to estimate the kinematic corrections to the basic formula, deriving from the position and the extension of the interferometer, and discuss the analogy with the Aharonov-Bohm effect. We show that the formula for the Sagnac time delay is the same for matter and light beams in arbitrary stationary space-times, provided that a suitable condition on the speed of the beams is fulfilled. Hence, the same results obtained for light beams apply to matter beams.
Ruggiero, Matteo Luca
Method and apparatus for monitoring characteristics of a high energy neutral beam. A neutral beam is generated by passing accelerated ions through a walled cell containing a low energy neutral gas, such that charge exchange neutralizes the high energy ion beam. The neutral beam is monitored by detecting the current flowing through the cell wall produced by low energy ions which drift to the wall after the charge exchange. By segmenting the wall into radial and longitudinal segments various beam conditions are further identified.
Fink, Joel H. (Livermore, CA)
The Spallation Neutron Source (SNS) to be constructed at ORNL is a collaboration of six laboratories. Beam current monitors for SNS will be used to monitor H-minus and H-plus beams ranging from the 15 mA (tune-up in the Front End and Linac) to over 60 A fully accumulated in the Ring. The time structure of the beams to be measured range from 645 nsec ''mini'' bunches, at the 1.05 MHz ring revolution rate, to an overall 1 mS long macro pulse. Beam current monitors (BCMs) for SNS have requirements depending upon their location within the system. The development of a general approach to satisfy requirements of various locations with common components is a major design objective. This paper will describe the development of the beam current monitors and electronics.
Neutron measurements from beam-target reactions at the ELISE neutral beam test facility
Measurements of 2.5 MeV neutron emission from beam-target reactions performed at the ELISE neutral beam test facility are presented in this paper. The measurements are used to study the penetration of a deuterium beam in a copper dump, based on the observation of the time evolution of the neutron counting rate from beam-target reactions with a liquid scintillation detector. A calculation based on a local mixing model of deuterium deposition in the target up to a concentration of 20% at saturation is used to evaluate the expected neutron yield for comparison with data. The results are of relevance to understand neutron emission associated to beam penetration in a solid target, with applications to diagnostic systems for the SPIDER and MITICA Neutral Beam Injection prototypes.
Xufei, X., E-mail: firstname.lastname@example.com; Fan, T. [State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Nocente, M.; Gorini, G. [Dipartimento di Fisica �G. Occhialini�, Universit� di Milano-Bicocca, Milano 20216 (Italy); Istituto di Fisica del Plasma �P. Caldirola�, Milano 20216 (Italy); Bonomo, F. [Consorzio RFX, Padova 35100 (Italy); Istituto Gas Ionizzati, CNR, Padova 35100 (Italy); Franzen, P.; Fr�schle, M. [Max-Planck-Institut f�r Plasmaphysik, Garching 84518 (Germany); Grosso, G.; Tardocchi, M. [Istituto di Fisica del Plasma �P. Caldirola�, Milano 20216 (Italy); Gr�nauer, F. [Physics Consulting, Zorneding 85604 (Germany); Pasqualotto, R. [Consorzio RFX, Padova 35100 (Italy)
Broadband microwave burst produced by electron beams
Theoretical and experimental study of fast electron beams attracts a lot of attention in the astrophysics and laboratory. In the case of solar flares the problem of reliable beam detection and diagnostics is of exceptional importance. This paper explores the fact that the electron beams moving oblique to the magnetic field or along the field with some angular scatter around the beam propagation direction can generate microwave continuum bursts via gyrosynchrotron mechanism. The characteristics of the microwave bursts produced by beams differ from those in case of isotropic or loss-cone distributions, which suggests a new tool for quantitative diagnostics of the beams in the solar corona. To demonstrate the potentiality of this tool, we analyze here a radio burst occurred during an impulsive flare 1B/M6.7 on 10 March 2001 (AR 9368, N27W42). Based on detailed analysis of the spectral, temporal, and spatial relationships, we obtained firm evidence that the microwave continuum burst is produced by electron beams. For the first time we developed and applied a new forward fitting algorithm based on exact gyrosynchrotron formulae and employing both the total power and polarization measurements to solve the inverse problem of the beam diagnostics. We found that the burst is generated by a oblique beam in a region of reasonably strong magnetic field ($\\sim 200-300$ G) and the burst is observed at a quasi-transverse viewing angle. We found that the life time of the emitting electrons in the radio source is relatively short, $\\tau_l \\approx 0.5$ s, consistent with a single reflection of the electrons from a magnetic mirror at the foot point with the stronger magnetic field. We discuss the implications of these findings for the electron acceleration in flares and for beam diagnostics.
A. T. Altyntsev; G. D. Fleishman; G. -L. Huang; V. F. Melnikov
Disruption effects on the beam size measurement
At the SLC Final Focus with higher currents and smaller beam sizes, the disruption parameter D{sub y} is close to one and so the pinch effect should produce a luminosity enhancement. Since a flat beam-beam function is fit to deflection scan data to measure the beam size, disruption can affect the measurement. Here the authors discuss the quantitative effects of disruption for typical SLC beam parameters. With 3.5 10{sup 10} particles per pulse, bunch length of 0.8 mm and beam sizes of 2.1 {mu}m horizontally and 0.55 {mu}m vertically, the measured vertical size can be as much as 25% bigger than the real one. Furthermore during the collision the spot size actually decrease, producing an enhancement factor H{sub D} of about 1.25. This would yield to a true luminosity which is 1.6 times that which is estimated from the beam-beam deflection fit.
Raimondi, P.; Decker, F.J.; Chen, P.
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Gas Gas and Thermal Photon Scattering in the NLC Main Linac as a Source of Beam Halo P. Tenenbaum LCC-Note-0051 12-JAN-2001 Abstract Scattering of primary beam electrons off of residual gas molecules or blackbody radiation photons in the NLC main linac has been identified as a potential source of beam haloes which must be collimated in the beam delivery system. We consider the contributions from four scat- tering mechanisms: inelastic thermal-photon scattering, elastic beam-gas (Coulomb) scattering inelastic beam-gas (Bremsstrahlung) scattering, and atomic-electron scattering. In each case we develop the formalism necessary to estimate the backgrounds generated in the main linac, and determine the expected number of off-energy or large-amplitude particles from each process, assuming a main linac injection energy of 8 GeV and extraction energy of 500 GeV. 1 Introduction The
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Facilities » Facilities » Ion Beam Materials Lab Ion Beam Materials Lab A new research frontier awaits! Our door is open and we thrive on mutually beneficial partnerships, collaborations that drive innovations and new technologies. April 12, 2012 Ion Beam Danfysik Implanter High Voltage Terminal. Contact Yongqiang Wang (505) 665-1596 Email Devoted to the characterization and modification of surfaces through the use of ion beams The Ion Beam Materials Laboratory (IBML) is a Los Alamos National Laboratory resource devoted to the characterization and modification of surfaces through the use of ion beams. The IBML provides and operates the core facilities, while supporting the design and implementation of specific apparati needed for experiments requested by users of the facility. The result is a facility with
A fast, economical, and compact x-ray beam chopper with a small mass and a small moment of inertia whose rotation can be synchronized and phase locked to an electronic signal from an x-ray source and be monitored by a light beam is disclosed. X-ray bursts shorter than 2.5 microseconds have been produced with a jitter time of less than 3 ns.
McPherson, Armon (Oswego, IL); Mills, Dennis M. (Naperville, IL)
High sensitivity charge amplifier for ion beam uniformity monitor
An ion beam uniformity monitor for very low beam currents using a high-sensitivity charge amplifier with bias compensation. The ion beam monitor is used to assess the uniformity of a raster-scanned ion beam, such as used in an ion implanter, and utilizes four Faraday cups placed in the geometric corners of the target area. Current from each cup is integrated with respect to time, thus measuring accumulated dose, or charge, in Coulombs. By comparing the dose at each corner, a qualitative assessment of ion beam uniformity is made possible. With knowledge of the relative area of the Faraday cups, the ion flux and areal dose can also be obtained.
Johnson, Gary W. (Livermore, CA)
Small beam nonparaxiality arrests selffocusing of optical beams Gadi Fibich
Small beam nonparaxiality arrests selffocusing of optical beams Gadi Fibich Departmentfocusing in the presence of small beam nonparaxiality is derived. Analysis of this equation shows that nonparaxiality remains small as the beam propa gates. Nevertheless, nonparaxiality arrests selffocusing when the beam
Soatto, Stefano
Applications of power beaming from space-based nuclear power stations. [Laser beaming to airplanes; microwave beaming to ground
Power beaming from space-based reactor systems is examined using an advanced compact, lightweight Rotating Bed Reactor (RBR). Closed Brayton power conversion efficiencies in the range of 30 to 40% can be achieved with turbines, with reactor exit temperatures on the order of 2000/sup 0/K and a liquid drop radiator to reject heat at temperatures of approx. 500/sup 0/K. Higher RBR coolant temperatures (up to approx. 3000/sup 0/K) are possible, but gains in power conversion efficiency are minimal, due to lower expander efficiency (e.g., a MHD generator). Two power beaming applications are examined - laser beaming to airplanes and microwave beaming to fixed ground receivers. Use of the RBR greatly reduces system weight and cost, as compared to solar power sources. Payback times are a few years at present prices for power and airplane fuel.
Powell, J.R.; Botts, T.E.; Hertzberg, A.
A design and fabrication effort for a beam director is documented. The conceptual design provides for the beam to pass first through a bending and focusing system (or ''achromat''), through a second achromat, through an air-to-vacuum interface (the ''beam window''), and finally through the vernier steering system. Following an initial concept study for a beam director, a prototype permanent magnet 30/sup 0/ beam-bending achromat and prototype vernier steering magnet were designed and built. In volume II, copies are included of the funding instruments, requests for quotations, purchase orders, a complete set of as-built drawings, magnetic measurement reports, the concept design report, and the final report on the design and fabrication project. (LEW)
Younger, F.C.
Neutrino Factories and Beta Beams
a Neutrino Factory Based on Muon Beams,� Proc. 2001 ParticleMD. [19] C. Rubbia et al. , �Beam Cooling with Ionisationthe required unstable ion beams has recently been suggested
Zisman, Michael S.
Beam profile effects on NPB performance
A comparison of neutral particle beam (NPB) brightness for various neutral beam profiles indicates that the widely used assumption of a Gaussian profile may be misleading for collisional neutralizers. An analysis of available experimental evidence shows that lower peaks and higher tails, compared to a Gaussian beam profile, are observed out of collisional neutralizers, which implies that peak brightness is over estimated, and for a given NPB platform-to-target range, the beam current (power), dwell time or some combination of such engagement parameters would have to be altered to maintain a fixed dose on the target. Based on the present analysis, this factor is nominally about 2.4 but may actually be as low as 1.8 or as high as 8. This is an important consideration in estimating NPB constellation performance in SDI engagement contexts.
Leclaire, R.J. Jr.; Bunker, W.J.
Systems and methods of varying charged particle beam spot size
Methods and devices enable shaping of a charged particle beam. A modified dielectric wall accelerator includes a high gradient lens section and a main section. The high gradient lens section can be dynamically adjusted to establish the desired electric fields to minimize undesirable transverse defocusing fields at the entrance to the dielectric wall accelerator. Once a baseline setting with desirable output beam characteristic is established, the output beam can be dynamically modified to vary the output beam characteristics. The output beam can be modified by slightly adjusting the electric fields established across different sections of the modified dielectric wall accelerator. Additional control over the shape of the output beam can be excreted by introducing intentional timing de-synchronization offsets and producing an injected beam that is not fully matched to the entrance of the modified dielectric accelerator.
Chen, Yu-Jiuan
Fast Beam Current Change Monitor for the LHC
Stringent demands on the LHC safety and protection systems require improved methods of detecting fast beam losses. The Fast Beam Current Transformer (FBCT) is a measurement instrument, providing information about bunch-to-bunch intensity of the accelerated beam. This thesis describes the development of a new protection system based on the FBCT signal measurements. This system, the Fast Beam Current Change Monitor (FBCCM), measures the FBCT signal in a narrow frequency band and computes time derivation of the beam signal magnitude. This derivation is proportional to the beam losses. When the losses exceed a certain level, the FBCCM requests a beam dump in order to protect the LHC. The LHC protection will be ensured by four FBCCMs which will be installed into the LHC in July 2014. Six FBCCMs have been already constructed and their characteristics were measured with satisfactory results. The FBCCMs were tested by a laboratory simulation of the real LHC environment.
Kral, Jan
Challenges in Accelerator Beam Instrumentation
The challenges in beam instrumentation and diagnostics for present and future particle accelerator projects are presented. A few examples for advanced hadron and lepton beam diagnostics are given.
Wendt, M.
Beta-beams is a new concept for the production of intense and pure neutrino beams. It is at the basis of a proposed neutrino facility, whose main goal is to explore the possible existence of CP violation in the lepton sector. Here we briefly review the original scenario and the low energy beta-beam. This option would offer a unique opportunity to perform neutrino interaction studies of interest for particle physics, astrophysics and nuclear physics. Other proposed scenarios for the search of CP violation are mentioned.
C. Volpe
Hohlraum Symmetry Experiments with Multiple Beam Cones on the Omega Laser Facility
Symmetry experiments have been performed on the Omega laser facility using cylindrical hohlraum targets with as many as 40thinspthinspbeams arranged into multiple beam cones. These experiments constitute a first step in the development of {open_quotes}beam phasing{close_quotes} in which beams are arranged into multiple beam cones, forming multiple rings of beam spots on the inner surface of a cylindrical hohlraum, and demonstrate the ability to model hohlraums incorporating multiple beam cones and to tune the time-integrated capsule flux asymmetry by adjustment of the beam pointing. {copyright} {ital 1998} {ital The American Physical Society}
Murphy, T.J.; Wallace, J.M.; Delamater, N.D.; Barnes, C.W.; Gobby, P.; Hauer, A.A.; Lindman, E.; Magelssen, G.; Moore, J.B.; Oertel, J.A.; Watt, R. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)] [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Landen, O.L.; Amendt, P.; Cable, M.; Decker, C.; Hammel, B.A.; Koch, J.A.; Suter, L.J.; Turner, R.E.; Wallace, R.J. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)] [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Marshall, F.J.; Bradley, D.; Craxton, R.S.; Keck, R.; Knauer, J.P.; Kremens, R.; Schnittman, J.D. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14627 (United States)] [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14627 (United States)
Neutral particle beam intensity controller
The neutral beam intensity controller is based on selected magnetic defocusing of the ion beam prior to neutralization. The defocused portion of the beam is dumped onto a beam dump disposed perpendicular to the beam axis. Selective defocusing is accomplished by means of a magnetic field generator disposed about the neutralizer so that the field is transverse to the beam axis. The magnetic field intensity is varied to provide the selected partial beam defocusing of the ions prior to neutralization. The desired focused neutral beam portion passes along the beam path through a defining aperture in the beam dump, thereby controlling the desired fraction of neutral particles transmitted to a utilization device without altering the kinetic energy level of the desired neutral particle fraction. By proper selection of the magnetic field intensity, virtually zero through 100% intensity control of the neutral beam is achieved.
Dagenhart, W.K.
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Beam Physics Beam Physics The following is an incomplete listing of course available for beam physics. United States Particle Accelerator School The US Particle Accelerator School provides educational programs in the field of beams and their associated accelerator technologies not otherwise available to the community of science and technology. Joint Universities Accelerator School Each year JUAS provides a foundation course on accelerator physics and associated technologies. The US-CERN-Japan-Russia Joint Accelerator School The purpose of the US-CERN-Japan-Russia joint school is to better our relations by working together on an advanced topical course every two years, alternating between the U.S., western Europe, Japan and Russia. The last set of courses focused on the frontiers of accelerator technology in
A focused ion beam (FIB) system produces a final beam spot size down to 0.1 {mu}m or less and an ion beam output current on the order of microamps. The FIB system increases ion source brightness by properly configuring the first (plasma) and second (extraction) electrodes. The first electrode is configured to have a high aperture diameter to electrode thickness aspect ratio. Additional accelerator and focusing electrodes are used to produce the final beam. As few as five electrodes can be used, providing a very compact FIB system with a length down to only 20 mm. Multibeamlet arrangements with a single ion source can be produced to increase throughput. The FIB system can be used for nanolithography and doping applications for fabrication of semiconductor devices with minimum feature sizes of 0.1 m or less. 13 figs.
Leung, K.; Gough, R.A.; Ji, Q.; Lee, Y.Y.
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Beamline Spectrometry Both ATF beam lines have dipoles, which serve as spectrometers, the vacuum chambers on of these dipoles also have zero degree ports that may be covered with a...
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Beam Schedule (pdf) Beam Schedule (pdf) Sunday Monday Tuesday Wednesday Thursday Friday Saturday 22 1/2 Holiday Holiday 28 January Holiday 4 5 Maintenance 11 12 Maintenance 18 19 Holiday AE52 - DWFA (Euclid), BL2 25 February AE52 - DWFA (Euclid), BL2 1 2 AE50 - PWFA in QNR (UCLA), BL2 8 9 AE50 - PWFA in QNR (UCLA), BL2 15 16 Holiday AE50 - PWFA in QNR (UCLA), BL2 22 March 1 2 AE53 - Nonlinear Compton (UCLA) 8 9 AE53 - Nonlinear Compton (UCLA) 15 16 AE53 - Nonlinear Compton (UCLA) 22 23 29 Sunday Monday Tuesday Wednesday Thursday Friday Saturday User operations (E-beam in use) Ions - Ion generation User operations (laser in use) PWFA - Plasma Wakefield Acceleration User operations (E-beam and laser in use)
E-Print Network 3.0 - alkali ion beams Sample Search Results
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beams Search Powered by Explorit Topic List Advanced Search Sample search results for: alkali ion beams Page: << < 1 2 3 4 5 > >> 1 METHOD FOR EFFICIENCY AND TIME RESPONSE...
E-Print Network 3.0 - argon 38 beams Sample Search Results
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beams Search Powered by Explorit Topic List Advanced Search Sample search results for: argon 38 beams Page: << < 1 2 3 4 5 > >> 1 Studies of a Liquid Argon Time Projection Chamber...
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Small Spot, Brighter Beam Small Spot, Brighter Beam Small Spot, Brighter Beam Print Do you notice the brighter beam? During the most recent shutdown, all of the corrector magnets were replaced with sextupoles, reducing the horizontal emittance and increasing beam brightness. "This is part of ongoing improvement to keep the ALS on the cutting edge," says Alastair MacDowell, a beamline scientist on Beamline 12.2.2. The brightness has increased by a factor of about three in the storage ring. Beamlines on superbend or center-bend magnets will see the most noticeable increase in brightness, but the horizontal beam size and divergence have been substantially reduced at all beamlines. "We are starting to approach the resolution of many beamlines. Therefore, not every beamline will be able to resolve the full improvement," says Christoph Steier, project leader of the brightness upgrade. Though superbend and center-bend magnet source sizes are reduced by roughly a factor of three, "measured improvements so far range from a factor of 2-2.5," Steier says. He and MacDowell agree that the beamline optics are likely the limiting factor in resolving the full improvement at the beamlines.
Wire Scanner Beam Profile Measurements: LANSCE Facility Beam Development
The Los Alamos Neutron Science Center (LANSCE) is replacing Wire Scanner (WS) beam profile measurement systems. Three beam development tests have taken place to test the new wire scanners under beam conditions. These beam development tests have integrated the WS actuator, cable plant, electronics processors and associated software and have used H{sup -} beams of different beam energy and current conditions. In addition, the WS measurement-system beam tests verified actuator control systems for minimum profile bin repeatability and speed, checked for actuator backlash and positional stability, tested the replacement of simple broadband potentiometers with narrow band resolvers, and tested resolver use with National Instruments Compact Reconfigurable Input and Output (cRIO) Virtual Instrumentation. These beam tests also have verified how trans-impedance amplifiers react with various types of beam line background noise and how noise currents were not generated. This paper will describe these beam development tests and show some resulting data.
Gilpatrick, John D. [Los Alamos National Laboratory; Batygin, Yuri K. [Los Alamos National Laboratory; Gonzales, Fermin [Los Alamos National Laboratory; Gruchalla, Michael E. [Los Alamos National Laboratory; Kutac, Vincent G. [Los Alamos National Laboratory; Martinez, Derwin [Los Alamos National Laboratory; Sedillo, James Daniel [Los Alamos National Laboratory; Pillai, Chandra [Los Alamos National Laboratory; Rodriguez Esparza, Sergio [Los Alamos National Laboratory; Smith, Brian G. [Los Alamos National Laboratory
Apparatus and method for laser beam diagnosis
An apparatus and method is disclosed for accurate, real time monitoring of the wavefront curvature of a coherent laser beam. Knowing the curvature, it can be quickly determined whether the laser beam is collimated, or focusing (converging), or de-focusing (diverging). The apparatus includes a lateral interferometer for forming an interference pattern of the laser beam to be diagnosed. The interference pattern is imaged to a spatial light modulator (SLM), whose output is a coherent laser beam having an image of the interference pattern impressed on it. The SLM output is focused to obtain the far-field diffraction pattern. A video camera, such as CCD, monitors the far-field diffraction pattern, and provides an electrical output indicative of the shape of the far-field pattern. Specifically, the far-field pattern comprises a central lobe and side lobes, whose relative positions are indicative of the radius of curvature of the beam. The video camera's electrical output may be provided to a computer which analyzes the data to determine the wavefront curvature of the laser beam.
Salmon, Jr., Joseph T. (Livermore, CA)
Apparatus and method for laser beam diagnosis
An apparatus and method are disclosed for accurate, real time monitoring of the wavefront curvature of a coherent laser beam. Knowing the curvature, it can be quickly determined whether the laser beam is collimated, or focusing (converging), or de-focusing (diverging). The apparatus includes a lateral interferometer for forming an interference pattern of the laser beam to be diagnosed. The interference pattern is imaged to a spatial light modulator (SLM), whose output is a coherent laser beam having an image of the interference pattern impressed on it. The SLM output is focused to obtain the far-field diffraction pattern. A video camera, such as CCD, monitors the far-field diffraction pattern, and provides an electrical output indicative of the shape of the far-field pattern. Specifically, the far-field pattern comprises a central lobe and side lobes, whose relative positions are indicative of the radius of curvature of the beam. The video camera's electrical output may be provided to a computer which analyzes the data to determine the wavefront curvature of the laser beam. 11 figures.
Salmon, J.T. Jr.
Full Counting Statistics of Stationary Particle Beams
We present a general scheme for treating particle beams as many particle systems. This includes the full counting statistics and the requirements of Bose/Fermi symmetry. In the stationary limit, i.e., for longer and longer beams, the total particle number diverges, and a description in Fock space is no longer possible. We therefore extend the formalism to include stationary beams. These beams exhibit a well-defined "local" counting statistics, by which we mean the full counting statistics of all clicks falling into any given finite interval. We treat in detail a model of a source, creating particles in a fixed state, which then evolve under the free time evolution, and we determine the resulting stationary beam in the far field. In comparison to the one-particle picture we obtain a correction due to Bose/Fermi statistics, which depends on the emission rate. We also consider plane waves as stationary many particle states, and determine the distribution of intervals between successive clicks in such a beam.
J. Kiukas; A. Ruschhaupt; R. F. Werner
Single element laser beam shaper
A single lens laser beam shaper for converting laser beams from any spatial profile to a flat-top or uniform spatial profile. The laser beam shaper includes a lens having two aspheric surfaces. The beam shaper significantly simplifies the overall structure in comparison with conventional 2-element systems and therefore provides great ease in alignment and reduction of cost.
Zhang, Shukui (Yorktown, VA); Michelle D. Shinn (Newport News, VA)
Method and apparatus for measuring properties of particle beams using thermo-resistive material properties
A beam position detector for measuring the properties of a charged particle beam, including the beam's position, size, shape, and intensity. One or more absorbers are constructed of thermo-resistive material and positioned to intercept and absorb a portion of the incoming beam power, thereby causing local heating of each absorber. The local temperature increase distribution across the absorber, or the distribution between different absorbers, will depend on the intensity, size, and position of the beam. The absorbers are constructed of a material having a strong dependence of electrical resistivity on temperature. The beam position detector has no moving parts in the vicinity of the beam and is especially suited to beam areas having high ionizing radiation dose rates or poor beam quality, including beams dispersed in the transverse direction and in their time radio frequency structure.
Degtiarenko, Pavel V. (Williamsburg, VA); Dotson, Danny Wayne (Gloucester, VA)
Recent study of beam stability in the PSR
A fast transverse instability with beam loss has been observed in the 800 MeV Los Alamos Pro Ring (PSR) when the injected beam intensity reaches 2 - 4 {times} 10{sup 13} protons per pulse. Previous observations in that the instability is most likely driven by electrons trapped within the proton beam. Theoretical study shown that beam leakage into the inter-bunch gap leads to electron trapping. Recent experiments were carried out by using the newly implemented ``pinger`` and by varying the machine transition gamma to explore further the ``e-p`` instability and the nature of the instability. This paper summarizes some of these recent experimental results and theoretical studies.
Wang, T.S.F.; Cooper, R.; Fitzgerald, D.; Frankle, S.; Hardek, T.; Hutson, R.; Macek, R.; Ohmori, C.; Plum, M.; Thiessen, H.; Wilkinson, C. [Los Alamos National Lab., NM (United States); Colton, E. [USDOE, Washington, DC (United States); Neuffer, D. [CEBAF, Newport News, VA (United States); Rees, G. [Rutherford Appleton Lab., Chilton (United Kingdom)
Recent study of beam stability in the PSR
A fast transverse instability with beam loss has been observed in the 800 MeV Los Alamos Pro Ring (PSR) when the injected beam intensity reaches 2 - 4 [times] 10[sup 13] protons per pulse. Previous observations in that the instability is most likely driven by electrons trapped within the proton beam. Theoretical study shown that beam leakage into the inter-bunch gap leads to electron trapping. Recent experiments were carried out by using the newly implemented pinger'' and by varying the machine transition gamma to explore further the e-p'' instability and the nature of the instability. This paper summarizes some of these recent experimental results and theoretical studies.
Wang, T.S.F.; Cooper, R.; Fitzgerald, D.; Frankle, S.; Hardek, T.; Hutson, R.; Macek, R.; Ohmori, C.; Plum, M.; Thiessen, H.; Wilkinson, C. (Los Alamos National Lab., NM (United States)); Colton, E. (USDOE, Washington, DC (United States)); Neuffer, D. (CEBAF, Newport News, VA (United States)); Rees, G. (Rutherford Appleton Lab., Chilton (United Kingdom))
TESLA Report 2004-03 Comparison of Stripline and Cavity Beam
characteristics of a beam position monitor (BPM) are position and time resolutions. Position resolution is the smallest deflection of the beam which a BPM can sense. Time resolution is the time which a BPM needs be performed, the BPM time resolution should be shorter than the distance between bunches. Different types
Beam Profile Monitor With Accurate Horizontal And Vertical Beam Profiles
A widely used scanner device that rotates a single helically shaped wire probe in and out of a particle beam at different beamline positions to give a pair of mutually perpendicular beam profiles is modified by the addition of a second wire probe. As a result, a pair of mutually perpendicular beam profiles is obtained at a first beamline position, and a second pair of mutually perpendicular beam profiles is obtained at a second beamline position. The simple modification not only provides more accurate beam profiles, but also provides a measurement of the beam divergence and quality in a single compact device.
Havener, Charles C [Knoxville, TN; Al-Rejoub, Riad [Oak Ridge, TN
From several neutrino oscillation experiments, we understand now that neutrinos have mass. However, we really don't know what mechanism is responsible for producing this neutrino mass. Current or planned neutrino experiments utilize neutrino beams and long-baseline detectors to explore flavor mixing but do not address the question of the origin of neutrino mass. In order to answer that question, neutrino interactions need to be explored at much higher energies. This paper outlines a program to explore neutrinos and their interactions with various particles through a series of experiments involving colliding neutrino beams.
Reinhard Schwienhorst
Non-Paraxial Accelerating Beams
We present the spatially accelerating solutions of the Maxwell equations. Such non-paraxial beams accelerate in a circular trajectory, thus generalizing the concept of Airy beams. For both TE and TM polarizations, the beams exhibit shape-preserving bending with sub-wavelength features, and the Poynting vector of the main lobe displays a turn of more than 90 degrees. We show that these accelerating beams are self-healing, analyze their properties, and compare to the paraxial Airy beams. Finally, we present the new family of periodic accelerating beams which can be constructed from our solutions.
Ido Kaminer; Rivka Bekenstein; Jonathan Nemirovsky; Mordechai Segev
An improved pulsed ion beam source is disclosed having a new biasing circuit for the fast magnetic field. This circuit provides for an initial negative bias for the field created by the fast coils in the ion beam source which pre-ionize the gas in the source, ionize the gas and deliver the gas to the proper position in the accelerating gap between the anode and cathode assemblies in the ion beam source. The initial negative bias improves the interaction between the location of the nulls in the composite magnetic field in the ion beam source and the position of the gas for pre-ionization and ionization into the plasma as well as final positioning of the plasma in the accelerating gap. Improvements to the construction of the flux excluders in the anode assembly are also accomplished by fabricating them as layered structures with a high melting point, low conductivity material on the outsides with a high conductivity material in the center. 12 figs.
Greenly, J.B.
A current sensor for measuring the dc component of a beam of charged particles employs a superconducting pick-up loop probe, with twisted superconducting leads in combination with a Superconducting Quantum Interference Device (SQUID) detector. The pick-up probe is in the form of a single-turn loop, or a cylindrical toroid, through which the beam is directed and within which a first magnetic flux is excluded by the Meisner effect. The SQUID detector acts as a flux-to-voltage converter in providing a current to the pick-up loop so as to establish a second magnetic flux within the electrode which nulls out the first magnetic flux. A feedback voltage within the SQUID detector represents the beam current of the particles which transit the pick-up loop. Meisner effect currents prevent changes in the magnetic field within the toroidal pick-up loop and produce a current signal independent of the beam's cross-section and its position within the toroid, while the combination of superconducting elements provides current measurement sensitivities in the nano-ampere range.
Kuchnir, M.; Mills, F.E.
A current sensor for measuring the DC component of a beam of charged particles employs a superconducting pick-up loop probe, with twisted superconducting leads in combination with a Superconducting Quantum Interference Device (SQUID) detector. The pick-up probe is in the form of a single-turn loop, or a cylindrical toroid, through which the beam is directed and within which a first magnetic flux is excluded by the Meisner effect. The SQUID detector acts as a flux-to-voltage converter in providing a current to the pick-up loop so as to establish a second magnetic flux within the electrode which nulls out the first magnetic flux. A feedback voltage within the SQUID detector represents the beam current of the particles which transit the pick-up loop. Meisner effect currents prevent changes in the magnetic field within the toroidal pick-up loop and produce a current signal independent of the beam's cross-section and its position within the toroid, while the combination of superconducting elements provides current measurement sensitivites in the nano-ampere range.
Kuchnir, Moyses (Elmhurst, IL); Mills, Frederick E. (Elburn, IL)
Beam control and diagnostic functions in the NIF transport spatial filter
Beam control and diagnostic systems are required to align the National Ignition Facility (NIF) laser prior to a shot as well as to provide diagnostics on 192 beam lines at shot time. A design that allows each beam`s large spatial filter lenses to also serve as objective lenses for beam control and diagnostic sensor packages helps to accomplish the task at a reasonable cost. However, this approach also causes a high concentration of small optics near the pinhole plane of the transport spatial filter (TSF) at the output of each beam. This paper describes the optomechanical design in and near the central vacuum vessel of the TSF.
Holdener, F.R.; Ables, E.; Bliss, E.S. [and others
Method and apparatus for efficient photodetachment and purification of negative ion beams
Methods and apparatus are described for efficient photodetachment and purification of negative ion beams. A method of purifying an ion beam includes: inputting the ion beam into a gas-filled multipole ion guide, the ion beam including a plurality of ions; increasing a laser-ion interaction time by collisional cooling the plurality of ions using the gas-filled multipole ion guide, the plurality of ions including at least one contaminant; and suppressing the at least one contaminant by selectively removing the at least one contaminant from the ion beam by electron photodetaching at least a portion of the at least one contaminant using a laser beam.
Beene, James R. (Oak Ridge, TN) [Oak Ridge, TN; Liu, Yuan (Knoxville, TN) [Knoxville, TN; Havener, Charles C. (Knoxville, TN) [Knoxville, TN
Neutral particle beam intensity controller
A neutral beam intensity controller is provided for a neutral beam generator in which a neutral beam is established by accelerating ions from an ion source into a gas neutralizer. An amplitude modulated, rotating magnetic field is applied to the accelerated ion beam in the gas neutralizer to defocus the resultant neutral beam in a controlled manner to achieve intensity control of the neutral beam along the beam axis at constant beam energy. The rotating magnetic field alters the orbits of ions in the gas neutralizer before they are neutralized, thereby controlling the fraction of neutral particles transmitted out of the neutralizer along the central beam axis to a fusion device or the like. The altered path or defocused neutral particles are sprayed onto an actively cooled beam dump disposed perpendicular to the neutral beam axis and having a central open for passage of the focused beam at the central axis of the beamline. Virtually zero therough 100% intensity control is achieved by varying the magnetic field strength without altering the ion source beam intensity or its species yield.
Dagenhart, William K. (Oak Ridge, TN)
Compensation techniques in NIRS proton beam radiotherapy
Proton beam has the dose distribution advantage in radiation therapy, although it has little advantage in biological effects. One of the best advantages is its sharp fall off of dose after the peak. With proton beam, therefore, the dose can be given just to cover a target volume and potentially no dose is delivered thereafter in the beam direction. To utilize this advantage, bolus techniques in conjunction with CT scanning are employed in NIRS proton beam radiation therapy planning. A patient receives CT scanning first so that the target volume can be clearly marked and the radiation direction and fixation method can be determined. At the same time bolus dimensions are calculated. The bolus frames are made with dental paraffin sheets according to the dimensions. The paraffin frame is replaced with dental resin. Alginate (a dental impression material with favorable physical density and skin surface contact) is now employed for the bolus material. With fixation device and bolus on, which are constructed individually, the patient receives CT scanning again prior to a proton beam treatment in order to prove the devices are suitable. Alginate has to be poured into the frame right before each treatments. Further investigations are required to find better bolus materials and easier construction methods.
Akanuma, A. (Univ. of Tokyo, Japan); Majima, H.; Furukawa, S.
Optical diagnosis of electron beam in the ''Pakhra'' synchroton
This article presents results of a study of the dynamics of the electron-beam cross section in the ''Pakhra'' synchrotron with electron acceleration to 670 MeV. The observed dependence of the rms amplitudes of vertical oscillations on time in one acceleration cycle is in good agreement with radiation-damping theory. The time dependence of the horizontal beam dimension is in satisfactory agreement with theory, assuming that the initial dimension is dependent only on synchrotron oscillations.
Bashmakov, Y.A.; Karpov, V.A.; Yarov, A.S.
PLASMA FOCUSING OF HIGH ENERGY DENSITY ELECTRON AND POSITRON BEAMS \\Lambda
PLASMA FOCUSING OF HIGH ENERGY DENSITY ELECTRON AND POSITRON BEAMS \\Lambda J.S.T. Ng, P. Chen, W, for the first time, positron beams. We also discuss measure ments on plasma lensinduced synchrotron radiation and laser and beamplasma interactions. 1 INTRODUCTION The plasma lens was proposed as a final focusing
High-Performance Beam Simulator for the LANSCE Linac
A high performance multiparticle tracking simulator is currently under development at Los Alamos. The heart of the simulator is based upon the beam dynamics simulation algorithms of the PARMILA code, but implemented in C++ on Graphics Processing Unit (GPU) hardware using NVIDIA's CUDA platform. Linac operating set points are provided to the simulator via the EPICS control system so that changes of the real time linac parameters are tracked and the simulation results updated automatically. This simulator will provide valuable insight into the beam dynamics along a linac in pseudo real-time, especially where direct measurements of the beam properties do not exist. Details regarding the approach, benefits and performance are presented.
Pang, Xiaoying [Los Alamos National Laboratory; Rybarcyk, Lawrence J. [Los Alamos National Laboratory; Baily, Scott A. [Los Alamos National Laboratory
Performance and Controllability of Pulsed Ion Beam Ablation Propulsion
We propose novel propulsion driven by ablation plasma pressures produced by the irradiation of pulsed ion beams onto a propellant. The ion beam ablation propulsion demonstrates by a thin foil (50 {mu}mt), and the flyer velocity of 7.7 km/s at the ion beam energy density of 2 kJ/cm2 adopted by using the Time-of-flight method is observed numerically and experimentally. We estimate the performance of the ion beam ablation propulsion as specific impulse of 3600 s and impulse bit density of 1700 Ns/m2 obtained from the demonstration results. In the numerical analysis, a one-dimensional hydrodynamic model with ion beam energy depositions is used. The control of the ion beam kinetic energy is only improvement of the performance but also propellant consumption. The spacecraft driven by the ion beam ablation provides high performance efficiency with short-pulsed ion beam irradiation. The numerical results of the advanced model explained latent heat and real gas equation of state agreed well with experimental ones over a wide range of the incident ion beam energy density.
Yazawa, Masaru; Buttapeng, Chainarong; Harada, Nobuhiro [Nagaoka University of Technology, Department of Electrical Engineering, 1603-1 Kamitomioka, Nagaoka, Niigata 940-2188 (Japan); Suematsu, Hisayuki; Jiang Weihua; Yatsui, Kiyoshi [Nagaoka University of Technology, Extreme Energy-Density Research Institute, 1603-1 Kamitomioka, Nagaoka, Niigata 940-2188 (Japan)
Gaussian Beams Enrique J. Galvez
Gaussian Beams Enrique J. Galvez Department of Physics and Astronomy Colgate University Copyright 2009 #12;ii #12;Contents 1 Fundamental Gaussian Beams 1 1.1 Spherical Wavefront in the Paraxial region . . . . . . . . . . . . . . . 1 1.2 Formal Solution of the Wave Equation . . . . . . . . . . . . . . . . . 3 1.2.1 Beam Spot w
Galvez, Enrique J. "Kiko"
Beam-beam interaction and Pacman effects in the SSC with random nonlinear multipoles
In order to find the combined effects of beam-beam interaction (head-on and long-range) and random nonlinear multipoles in dipole magnets, transverse tunes and smears have been calculated as a function of oscillation amplitudes. Two types of particles, ''regular'' and ''Pacman,'' have been investigated using a modified version of tracking code TEAPOT. Regular particles experience beam-beam interactions in all four interaction regions (IR's), both head-on and long range, while pacman particles interact with bunches of the other beam in one medium-beta and one low-beta IR's only. The model for the beam-beam interaction is of weak-strong type and the strong beam is assumed to have a round Gaussian charge distribution. Furthermore, it is assumed that the vertical closed orbit deviation arising from the finite crossing angle of 70 ..mu..rad is perfectly compensated for regular particles. The same compensation applied to pacman particles creates a closed orbit distortion. Linear tunes are adjusted for regular particles to the design values but there are no nonlinear corrections except for chromaticity correcting sextupoles in two families. Results obtained in this study do not show any reduction of dynamic or linear aperture for pacman particles but some doubts exist regarding the validity of defining the linear aperture from the smear alone. Preliminary results are given for regular particles when (..delta..p/p) is modulated by the synchrotron oscillation. For these, fifty oscillations corresponding to 26,350 revolutions have been tracked. A very slow increase in the horizontal amplitude, /approximately/4 /times/ 10/sup /minus/4//oscillation (relative), is a possibility but this should be confirmed by trackings of larger number of revolutions. 11 refs., 18 figs., 2 tabs.
Goderre, G.P.; Ohnuma, S.
Science Journals Connector (OSTI)
It is always important to test new imagers for a mosaic camera before device acceptance and constructing the mosaic. This is particularly true of the LSST CCDs due to the fast beam illumination: at long wavelengths there can be significant beam divergence (defocus) inside the silicon because of the long absorption length for photons near the band gap. Moreover, realistic sky scenes need to be projected onto the CCD focal plane Thus, we need to design and build an f/1.2 re-imaging system. The system must simulate the entire LSST1 operation, including a sky with galaxies and stars with approximately black-body spectra superimposed on a spatially diffuse night sky emission with its complex spectral features.
J A Tyson; J Sasian; C Claver; G Muller; K Gilmor; M Klint
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1598 29 1079 9 1070 3.8 3.8 20.1 78 Kr 77.920 40 3117 140 622 20 602 14.2 14.4 41.4 Proton 1.007 40 40 0.1 8148 1.2 8147 0.012 0.012 0.56 Available Beams 40 A MeV 25 A MeV 15 A MeV...
If the recently observed anomaly in the PVLAS experiment is due to the axion, then the powerful beams of synchrotron photons, propagating through high magnetic field of the HERA beamline, become strong axion sources. This gives a unique opportunity of detection of the axion-photon interactions by installing a small detector in the HERA tunnel, and to corroborate the axion hypothesis within a few days of running.
K. Piotrzkowski
It is proposed to build a regional outpatient medical clinic at the Fermi National Accelerator Laboratory (Fermilab), Batavia, Illinois, to exploit the unique therapeutic characteristics of high energy proton beams. The Fermilab location for a proton therapy facility (PTF) is being chosen for reasons ranging from lower total construction and operating costs and the availability of sophisticated technical support to a location with good access to patients from the Chicago area and from the entire nation. 9 refs., 4 figs., 26 tabs.
Not Available
Observation of Beam ION Instability in Spear3
Weak vertical coupled bunch instability with oscillation amplitude at {mu}m level has been observed in SPEAR3. The instability becomes stronger when there is a vacuum pressure rise by partially turning off vacuum pumps and it becomes weaker when the vertical beam emittance is increased by turning off the skew quadrupole magnets. These confirmed that the instability was driven by ions in the vacuum. The threshold of the beam ion instability when running with a single bunch train is just under 200 mA. This paper presents the comprehensive observations of the beam ion instability in SPEAR3. The effects of vacuum pressure, beam current, beam filling pattern, chromaticity, beam emittance and bunch-by-bunch feedback are investigated in great detail. In an electron accelerator, ions generated from the residual gas molecules can be trapped by the beam. Then these trapped ions interact resonantly with the beam and cause beam instability and emittance blow-up. Most existing light sources use a long single bunch train filling pattern, followed by a long gap to avoid multi-turn ion trapping. However, such a gap does not preclude ions from accumulating during one passage of the single bunch train beam, and those ions can still cause a Fast Ion Instability (FII) as predicted by Raubenheimer and Zimmermann. FII has been observed in ALS, and PLS by artificially increasing the vacuum pressure by injecting helium gas into the vacuum chamber or by turning off the ion pumps in order to observe the beam ion instability. In some existing rings, for instance B factory, the beam ion instability was observed at the beginning of the machine operation after a long period of shutdown and then it automatically disappeared when the vacuum was better. However, when the beam emittance becomes smaller, the FII can occur at nominal conditions as observed in PLS, SOLEIL and SSRF. This paper reports the observations of beam ion instabilities in SPEAR3 under different condition during a period of one year, which includes single bunch train instability (FII) and multi-bunch train instability. Note that the instability may be not the same even with the same beam due to the change of the vacuum with time. SPEAR3 has a circumference of 234 m with a harmonic number of 372. SPEAR3 runs with six bunch train filling pattern in order to suppress the possible beam ion instability. Table 1 lists the main parameters of SPEAR3. The vacuum of SPEAR3 ranges from 0.1 to 0.5 nTorr, which varies from section to section.
Teytelman, D.; /Dimtel, Redwood City; Cai, Y.; Corbett, W.J.; Raubenheimer, T.O.; Safranek, J.A.; Schmerge, J.F.; Sebek, J.J.; Wang, L.; /SLAC
A compact molecular beam machine
We have developed a compact, low cost, modular, crossed molecular beam machine. The new apparatus utilizes several technological advancements in molecular beams valves, ion detection, and vacuum pumping to reduce the size, cost, and complexity of a molecular beam apparatus. We apply these simplifications to construct a linear molecular beam machine as well as a crossed-atomic and molecular beam machine. The new apparatus measures almost 50 cm in length, with a total laboratory footprint less than 0.25 m{sup 2} for the crossed-atomic and molecular beam machine. We demonstrate the performance of the apparatus by measuring the rotational temperature of nitric oxide from three common molecular beam valves and by observing collisional energy transfer in nitric oxide from a collision with argon.
Jansen, Paul [Vrije Universiteit, 1081 HV Amsterdam (Netherlands); Chandler, David W.; Strecker, Kevin E. [Sandia National Laboratories, Livermore, California 94551 (United States)
Australian Science and Technology with Relevance to Beamed Energy Propulsion
Although Australia has no Beamed Energy Propulsion programs at the present time, it is accomplishing significant scientific and technological activity that is of potential relevance to Beamed Energy Propulsion (BEP). These activities include: continual upgrading and enhancement of the Woomera Test Facility, Which is ideal for development and test of high power laser or microwave systems and the flight vehicles they would propel; collaborative development and test, with the US and UK of hypersonic missiles that embody many features needed by beam-propelled flight vehicles; hypersonic air breathing propulsion systems that embody inlet-engine-nozzle features needed for beam-riding agility by air breathing craft; and research on specially conditioned EM fields that could reduce beamed energy lost during atmospheric propagation.
Froning, H. David Jr [PO Box 180, Gumeracha SA 5233 (Australia)
Nondestructive Damage Detection in General Beams
is to provide NDE methodologies that simultaneously identify the location, the extent, and the severity of damage in general beams. By general beams, we mean beyond Euler-Bernoulli beams (i.e. slender beams) to deep beams and stubby beams whose response may...
Dincal, Selcuk
Power threshold for neutral beam current drive
For fully noninductive current drive in tokamaks using neutral beams, there is a power and density threshold condition, setting a minimum value for P{sup 3/2}/n{sup 2}. If this condition is not met, stationary state cannot occur, and a tokamak discharge will collapse. This is a consequence of the coupling between current and electron temperature, or between current drive efficiency and energy confinement time. 4 figs.
Politzer, P.A. (General Atomics, San Diego, CA (USA)); Porter, G.D. (Lawrence Livermore National Lab., CA (USA))
Beam-Beam Interaction Simulations with Guinea Pig
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5 5 SLAC-TN-03-070 September 2003 Beam-Beam Interaction Simulations with Guinea Pig C. Sramek, T. O. Raubenheimer, A. Seryi, M. Woods, J. Yu Stanford Linear Accelerator Center Stanford University Stanford, CA Abstract: At the interaction point of a particle accelerator, various phenomena occur that are known as beam-beam effects. Incident bunches of electrons (or positrons) experience strong electromagnetic fields from the opposing bunches, which leads to electron deflection, beamstrahlung and the creation of electron/positron pairs and hadrons due to two-photon exchange. In addition, the beams experience a "pinch effect" which focuses each beam and results in either a reduction or expansion of their vertical size. Finally, if a
The RHIC Beam Abort Kicker Power Supply Systems commissioning experience and the remaining issues will be reported in this paper. The RHIC Blue Ring Beam Abort Kicker Power Supply System initial commissioning took place in June 1999. Its identical system in Yellow Ring was brought on line during Spring 2000. Each of the RHIC Beam Abort Kicker Power Supply Systems consists of five high voltage modulators and subsystems. These systems are critical devices for RHIC machine protection and environmental protection. They are required to be effective, reliable and operating with sufficient redundancy to safely abort the beam to its beam dump at the end of accumulation or at any time when they are commanded. To deflect 66 GeV ion beam to the beam absorbers, the RHIC Beam Abort Kicker Power Supply Systems were operated at 22 kV level. The RHIC 2000 commissioning run was very successful.
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A macroscopic model for focused?ion?beam?induced deposition
Science Journals Connector (OSTI)
A time?dependent model for focused?ion?beam?induced deposition is presented which explicitly takes the scanning strategy of the beam during deposition into account. The model differentiates between the contribution of the beam center and that of the beam wings and contains all major experimental variables such as current density focus size scan speed and frame time. The deposition rate has been measured for tungsten as a function of the major experimental variables. The model has been fitted to these data and is found to describe the various dependences very well. By use of the model inclusive of the parameters obtained from the fit we can predict optimum deposition conditions. Furthermore the model clarifies effects observed during deposition on the structuredsurface of an integrated circuit such as redeposition of sputtered material and poor step coverage due to an impeded gas flow.
M. H. F. Overwijk; F. C. van den Heuvel
The performance of the MICE muon beam line
The Muon Ionization Cooling Experiment is one lattice cell of a cooling channel suitable for conditioning the muon beam at the front end of a Neutrino Factory or Muon Collider. The beam line designed to transport muons into MICE has been installed, and data was collected in 2010. In this paper the method of reconstructing longitudinal momentum and transverse trace space using two timing detectors is discussed, and a preliminary simulation of the performance of a measured beam in the cooling channel is presented.
Rayner, Mark Alastair [University of Oxford (United Kingdom)
A High Count Rate Neutron Beam Monitor for Neutron Scattering Facilities
Abstract Beam monitors are an important diagnostic tool in neutron science facilities. Present beam monitors use either ionization chambers in integration mode, which are slow and have no timing information, or pulse counters which can easily be saturated by high beam intensities. At high flux neutron scattering facilities, neutron beam monitors with very low intrinsic efficiency (10-5) are presently selected to keep the counting rate within a feasible range, even when a higher efficiency would improve the counting statistics and yield a better measurement of the incident beam. In this work, we report on a high count rate neutron beam monitor. This beam monitor offers good timing with an intrinsic efficiency of 10-3 and a counting rate capability of over 1,000,000 cps without saturation.
Barnett, Amanda [University of Tennessee, Knoxville (UTK); Crow, Lowell [ORNL; Diawara, Yacouba [ORNL; Hayward, J P [University of Tennessee, Knoxville (UTK); Hayward, Jason P [ORNL; Menhard, Kocsis [European Synchrotron Radiation Facility (ESRF); Sedov, Vladislav N [ORNL; Funk, Loren L [ORNL
Matching extended-SSD electron beams to multileaf collimated photon beams in the treatment of head and neck cancer
Purpose: Matching the penumbra of a 6 MeV electron beam to the penumbra of a 6 MV photon beam is a dose optimization challenge, especially when the electron beam is applied from an extended source-to-surface distance (SSD), as in the case of some head and neck treatments. Traditionally low melting point alloy blocks have been used to define the photon beam shielding over the spinal cord region. However, these are inherently time consuming to construct and employ in the clinical situation. Multileaf collimators (MLCs) provide a fast and reproducible shielding option but generate geometrically nonconformal approximations to the desired beam edge definition. The effects of substituting Cerrobend for the MLC shielding mode in the context of beam matching with extended-SSD electron beams are the subject of this investigation. Methods: Relative dose beam data from a Varian EX 2100 linear accelerator were acquired in a water tank under the 6 MeV electron beam at both standard and extended-SSD and under the 6 MV photon beam defined by Cerrobend and a number of MLC stepping regimes. The effect of increasing the electron beam SSD on the beam penumbra was assessed. MLC stepping was also assessed in terms of the effects on both the mean photon beam penumbra and the intraleaf dose-profile nonuniformity relative to the MLC midleaf. Computational techniques were used to combine the beam data so as to simulate composite relative dosimetry in the water tank, allowing fine control of beam abutment gap variation. Idealized volumetric dosimetry was generated based on the percentage depth-dose data for the beam modes and the abutment geometries involved. Comparison was made between each composite dosimetry dataset and the relevant ideal dosimetry dataset by way of subtraction. Results: Weighted dose-difference volume histograms (DDVHs) were produced, and these, in turn, summed to provide an overall dosimetry score for each abutment and shielding type/angle combination. Increasing the electron beam SSD increased the penumbra width (defined as the lateral distance of the 80% and 20% isodose contours) by 8-10 mm at the depths of 10-20 mm. Mean photon beam penumbra width increased with increased MLC stepping, and the mean MLC penumbra was {approx_equal}1.5 times greater than that across the corresponding Cerrobend shielding. Intraleaf dose discrepancy in the direction orthogonal to the beam edge also increased with MLC stepping. Conclusions: The weighted DDVH comparison techniques allowed the composite dosimetry resulting from the interplay of the abovementioned variables to be ranked. The MLC dosimetry ranked as good or better than that resulting from beam matching with Cerrobend for all except large field overlaps (-2.5 mm gap). The results for the linear-weighted DDVH comparison suggest that optimal MLC abutment dosimetry results from an optical surface gap of around 1{+-}0.5 mm. Furthermore, this appears reasonably lenient to abutment gap variation, such as that arising from uncertainty in beam markup or other setup errors.
Steel, Jared; Stewart, Allan; Satory, Philip [Auckland Regional Blood and Cancer Service, Auckland City Hospital, 2 Park Road, Grafton, Auckland 1023 (New Zealand)
Apparatus and method for increasing the bandwidth of a laser beam
A method and apparatus is disclosed that provides a laser output beam having a broad bandwidth and an intensity smooth over time. The bandwidth of the laser output can be varied easily by varying the intensity of a broadband source. The present invention includes an optical modulation apparatus comprising a narrowband laser that outputs a horizontally polarized beam (a "signal beam") and a broadband laser that outputs a vertically polarized beam (a "pump beam") whose intensity varies rapidly. The two beam are coupled into a birefringent laser material so that the respective polarizations coincide with the principal axes of the material. As the two beams travel through the material, the polarization preserving properties of the birefringent material maintain the respective polarizations of the two beam; however there is coupling between the two beams as a result of cross phase modulations, which induces a bandwidth change of the signal beam. The amount of bandwidth change is dependent upon the average intensity of the pump beam. The beams are coupled out from the birefringent material and the modulated signal beam is separated by a polarization selector. The modulated signal beam now has a wider bandwidth, and its shape remains smooth in time. This signal beam can be applied to incoherence inducing systems. The different bandwidths required by these different incoherence inducing systems can be obtained by varying the intensity of the pump beam. The United States Government has rights in this invention pursuant to Contract No. W7405-ENG-48 between the United States Department of Energy and the University of California for the operation of Lawrence Livermore National Laboratory.
Chaffee, Paul H. (Bolina, CA)
LANL: Ion Beam Materials Laboratory
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Ion Beam Materials Laboratory (IBML) is a Los Ion Beam Materials Laboratory (IBML) is a Los Alamos National Laboratory resource devoted to materi- als research through the use of ion beams. Current major research areas include surface characterization through ion beam analysis techniques, surface modification and materials synthesis through ion implantation technology, and radiation damage stud- ies in gases, liquids, and solids. The laboratory's core is a 3.2 MV tandem ion accelerator and a 200 kV ion implanter together with several beam lines. Attached to each beam line is a series of experimental stations that support various research programs. The operation of IBML and its interactions with users are organized around core facilities and experimental stations. The IBML provides and operates the core facilities as well as supports
We have designed two photon beam position monitors for use on our x-ray storage ring beam lines. In both designs, a pair of tungsten blades, separated by a pre-determined gap, intercepts a small fraction of the incoming beam. Due to photoemission, an electrical signal is generated which is proportional to the amount of beam intercepted. The thermal load deposited in the blade is transferred by a heat pipe to a heat exchanger outside the vacuum chamber. A prototype monitor with gap adjustment capability was fabricated and tested at a uv beam line. The results show that the generated electrical signal is a good measurement of the photon beam position. In the following sections, design features and test results are discussed.
Mortazavi, P.; Woodle, M.; Rarback, H.; Shu, D.; Howells, M.
Particle Detector / Beam Current Transformer
Particle Detector / Beam Current Transformer Analysis December 8, 2009 Harold G. Kirk #12;ShotSignal,A.U. Proton Bunch Number Beam Current Transformer - 17011 0 2 4 6 8 0 2 4 6 8 10 12 14 16 18 20 Integrated Transformer Pump 187829 (au) Probe 196504 (au) Ratios: Beam Current 1.046 SF 1.019 2.9% difference #12;Shot
McDonald, Kirk
Development of a fast position-sensitive laser beam detector
We report the development of a fast position-sensitive laser beam detector. The detector uses a fiber-optic bundle that spatially splits the incident beam, followed by a fast balanced photodetector. The detector is applied to the study of Brownian motion of particles on fast time scales with 1 A spatial resolution. Future applications include the study of molecule motors, protein folding, as well as cellular processes.
Chavez, Isaac; Huang Rongxin; Henderson, Kevin; Florin, Ernst-Ludwig; Raizen, Mark G. [Center for Nonlinear Dynamics and Department of Physics, University of Texas at Austin, Austin, Texas 78712 (United States)
A broad-band beam buncher is disclosed, comprising an evacuated housing, an electron gun therein for producing an electron beam, a buncher cavity having entrance and exit openings through which the beam is directed, grids across such openings, a source providing a positive DC voltage between the cavity and the electron gun, a drift tube through which the electron beam travels in passing through such cavity, grids across the ends of such drift tube, gaps being provided between the drift tube grids and the entrance and exit grids, a modulator for supplying an ultrahigh frequency modulating signal to the drift tube for producing velocity modulation of the electrons in the beam, a drift space in the housing through which the velocity modulated electron beam travels and in which the beam is bunched, and a discharge opening from such drift tube and having a grid across such opening through which the bunched electron beam is discharged into an accelerator or the like. The buncher cavity and the drift tube may be arranged to constitute an extension of a coaxial transmission line which is employed to deliver the modulating signal from a signal source. The extended transmission line may be terminated in its characteristic impedance to afford a broad-band response and the device as a whole designed to effect broad-band beam coupling, so as to minimize variations of the output across the response band.
Goldberg, David A. (Walnut Creek, CA); Flood, William S. (Berkeley, CA); Arthur, Allan A. (Martinez, CA); Voelker, Ferdinand (Orinda, CA)
The main goal of a beta-beam facility is to determine the possible existence of CP violation in the lepton sector, the value of the third neutrino mixing angle and the mass hierarchy. Here we argue that a much broader physics case can be covered since the beta-beam concept can also be used to establish a low energy beta-beam facility. We discuss that the availability of neutrino beams in the 100 MeV energy range offers a unique opportunity to perform neutrino scattering experiments of interest for nuclear physics, for the study of fundamental interactions and of core-collapse supernova physics.
Cristina Volpe
ANL Beams and Applications Seminar
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Formation of nanosize structures on a silicon substrate by method of focused ion beams
The results of experimental studies of modes in which nanosize structures are formed on a silicon substrate by method of focused ion beams are presented. Dependences of the diameter and depth of the nanosize structures on the ion beam current and time of exposure to the ion beam at a point are obtained. It is demonstrated that the main factor determining the rate of ion-beam milling is the ion beam current. The results of the study can be used in the development of technological processes for the fabrication of components for nanoelectronics and nanosystems engineering.
Ageev, O. A.; Kolomiytsev, A. S.; Konoplev, B. G., E-mail: firstname.lastname@example.com [Technological Institute of the Southern Federal University (Russian Federation)
Pulsed Helium Ion Beam Induced Deposition: A Means to High Growth Rates
The sub-nanometer beam of a helium ion microscope was used to study and optimize helium-ion beam induced deposition of PtC nanopillars with the (CH{sub 3}){sub 3}Pt(CPCH{sub 3}) precursor. The beam current, beam dwell time, precursor refresh time, and beam focus have been independently varied. Continuous beam exposure resulted in narrow but short pillars, while pulsed exposure resulted in thinner and higher ones. Furthermore, at short dwell times the deposition efficiency was very high, especially for a defocused beam. Efficiencies were measured up to 20 times the value for continuous exposure conditions. The interpretation of the experimental data was aided by a Monte Carlo simulation of the deposition. The results indicate that two regimes are operational in ion beam induced deposition (IBID). In the first one, the adsorbed precursor molecules originally present in the beam interaction region decompose. After the original precursor layer is consumed, further depletion is averted and growth continues by the supply of molecules via adsorption and surface diffusion. Depletion around the beam impact site can be distinguished from depletion on the flanges of the growing pillars. The Monte Carlo simulations for low precursor surface coverage reproduce measured growth rates, but predict considerably narrower pillars, especially at short dwell times. Both the experiments and the simulations show that the pillar width rapidly increases with increasing beam diameter. Optimal writing strategy, good beam focusing, and rapid beam positioning are needed for efficient and precise fabrication of extended and complex nanostructures by He-IBID.
Alkemade, Paul F. A. [Delft University of Technology, Delft, Netherlands; Miro, Hozanna [Delft University of Technology, Delft, Netherlands; Van Veldhoven, Emile [TNO Van Leeuwenhoek Laboratory; Maas, Diederick [TNO Van Leeuwenhoek Laboratory; Smith, Daryl [University of Tennessee, Knoxville (UTK); Rack, P. D. [University of Tennessee, Knoxville (UTK)
Collisionless relaxation in beam-plasma systems
This thesis reports the results from the theoretical investigations, both numerical and analytical, of collisionless relaxation phenomena in beam-plasma systems. Many results of this work can also be applied to other lossless systems of plasma physics, beam physics and astrophysics. Different aspects of the physics of collisionless relaxation and its modeling are addressed. A new theoretical framework, named Coupled Moment Equations (CME), is derived and used in numerical and analytical studies of the relaxation of second order moments such as beam size and emittance oscillations. This technique extends the well-known envelope equation formalism, and it can be applied to general systems with nonlinear forces. It is based on a systematic moment expansion of the Vlasov equation. In contrast to the envelope equation, which is derived assuming constant rms beam emittance, the CME model allows the emittance to vary through coupling to higher order moments. The CME model is implemented in slab geometry in the absence of return currents. The CME simulation yields rms beam sizes, velocity spreads and emittances that are in good agreement with particle-in-cell (PIC) simulations for a wide range of system parameters. The mechanism of relaxation is also considered within the framework of the CME system. It is discovered that the rapid relaxation or beam size oscillations can be attributed to a resonant coupling between different modes of the system. A simple analytical estimate of the relaxation time is developed. The final state of the system reached after the relaxation is complete is investigated. New and accurate analytical results for the second order moments in the phase-mixed state are obtained. Unlike previous results, these connect the final values of the second order moments with the initial beam mismatch. These analytical estimates are in good agreement with the CME model and PIC simulations. Predictions for the final density and temperature are developed that show main important features of the spatial dependence of the profiles. Different aspect of the final coarse-grained state such as its non-thermal nature, the appearance of 'hot' regions on the periphery and the core-halo character of the density are investigated.
Backhaus, Ekaterina Yu.
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1, 2002 Nov. 18, 2002 Nov. 25, 2002 Dec. 02, 2002 1, 2002 Nov. 18, 2002 Nov. 25, 2002 Dec. 02, 2002 Dec. 09, 2002 Dec. 16, 2002 Dec. 23, 2002 Dec. 30, 2002 Jan. 06, 2003 Jan. 13, 2003 Jan. 20, 2003 Jan. 27, 2003 Feb. 03, 2003 Feb. 10, 2003 Feb. 17, 2003 Feb. 24, 2003 Mar. 03, 2003 Mar. 10, 2003 Mar. 17, 2003 Mar. 24, 2003 Mar. 31, 2003 Back to Table of Contents WEEK OF Nov. 11, 2002 Nov. 11, 2002 Nov. 12, 2002 Nov. 13, 2002 Nov. 14, 2002 Nov. 15, 2002 Nov. 16, 2002 Nov. 17, 2002 BEAM LINE 1-4 Nov. 11, 2002 Nov. 12, 2002 Nov. 13, 2002 Nov. 14, 2002 Nov. 15, 2002 Nov. 16, 2002 Nov. 17, 2002 Unscheduled Unscheduled Unscheduled Unscheduled Unscheduled Unscheduled Unscheduled
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Nov. 04, 2013 Nov. 11, 2013 Nov. 18, 2013 Nov. 25, 2013 Nov. 04, 2013 Nov. 11, 2013 Nov. 18, 2013 Nov. 25, 2013 Dec. 02, 2013 Dec. 09, 2013 Dec. 16, 2013 Dec. 23, 2013 Dec. 30, 2013 Jan. 06, 2014 Jan. 13, 2014 Jan. 20, 2014 Jan. 27, 2014 Feb. 03, 2014 Back to Table of Contents WEEK OF Nov. 04, 2013 Ops Re-start Nov. 04, 2013 Nov. 05, 2013 Nov. 06, 2013 Nov. 07, 2013 Nov. 08, 2013 Nov. 09, 2013 Nov. 10, 2013 BEAM LINE 1-4 Nov. 04, 2013 Nov. 05, 2013 Nov. 06, 2013 Nov. 07, 2013 Nov. 08, 2013 Nov. 09, 2013 Nov. 10, 2013 DOWN DOWN DOWN 8891 C.TASSONE 8891 C.TASSONE 8891 C.TASSONE 8891 C.TASSONE
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1-4 1-4 Nov. 05, 2007 Nov. 06, 2007 Nov. 07, 2007 Nov. 08, 2007 Nov. 09, 2007 Nov. 10, 2007 Nov. 11, 2007 Unscheduled Unscheduled 8051 M.TONEY 8051 M.TONEY 8051 M.TONEY 8051 M.TONEY 8051 M.TONEY Unscheduled CHANGE/8051 M.TONE 8051 M.TONEY 8051 M.TONEY 8051 M.TONEY 8051 M.TONEY 8051 M.TONEY Unscheduled 8051 M.TONEY 8051 M.TONEY 8051 M.TONEY 8051 M.TONEY 8051 M.TONEY 8051 M.TONEY BEAM LINE 2-1 Nov. 05, 2007 Nov. 06, 2007 Nov. 07, 2007 Nov. 08, 2007 Nov. 09, 2007 Nov. 10, 2007 Nov. 11, 2007 8859 B.JOHNSON 8859 B.JOHNSON 8859 B.JOHNSON 8859 B.JOHNSON 3157* M.MONTERO-CA 3087 L.FUENTES-COB 3087 L.FUENTES-COB
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1-5 1-5 Nov. 28, 2005 Nov. 29, 2005 Nov. 30, 2005 Dec. 01, 2005 Dec. 02, 2005 Dec. 03, 2005 Dec. 04, 2005 MA 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ BEAM LINE 7-1 Nov. 28, 2005 Nov. 29, 2005 Nov. 30, 2005 Dec. 01, 2005 Dec. 02, 2005 Dec. 03, 2005 Dec. 04, 2005 MA DOWN DOWN DOWN DOWN DOWN DOWN
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5-4 5-4 Nov. 05, 2007 Nov. 06, 2007 Nov. 07, 2007 Nov. 08, 2007 Nov. 09, 2007 Nov. 10, 2007 Nov. 11, 2007 Unscheduled 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU CHANGE/8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU BEAM LINE 8-1 Nov. 05, 2007 Nov. 06, 2007 Nov. 07, 2007 Nov. 08, 2007 Nov. 09, 2007 Nov. 10, 2007 Nov. 11, 2007 8821 D.Brehmer 8821 D.Brehmer 8821 D.Brehmer 3064* S.SUN 3075 M.GARNER 3075 M.GARNER 3075 M.GARNER
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4, 2013 Nov. 11, 2013 Nov. 18, 2013 Nov. 25, 2013 4, 2013 Nov. 11, 2013 Nov. 18, 2013 Nov. 25, 2013 Dec. 02, 2013 Dec. 09, 2013 Dec. 16, 2013 Dec. 23, 2013 Dec. 30, 2013 Jan. 06, 2014 Jan. 13, 2014 Jan. 20, 2014 Jan. 27, 2014 Feb. 03, 2014 Back to Table of Contents WEEK OF Nov. 04, 2013 Ops Re-start Nov. 04, 2013 Nov. 05, 2013 Nov. 06, 2013 Nov. 07, 2013 Nov. 08, 2013 Nov. 09, 2013 Nov. 10, 2013 BEAM LINE 5-4 Nov. 04, 2013 Nov. 05, 2013 Nov. 06, 2013 Nov. 07, 2013 Nov. 08, 2013 Nov. 09, 2013 Nov. 10, 2013 DOWN DOWN DOWN DOWN DOWN DOWN DOWN
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1-4 1-4 Nov. 28, 2005 Nov. 29, 2005 Nov. 30, 2005 Dec. 01, 2005 Dec. 02, 2005 Dec. 03, 2005 Dec. 04, 2005 MA 8840 J.POPLE 8840 J.POPLE 8840 J.POPLE 8840 J.POPLE 8840 J.POPLE 8840 J.POPLE CHANGE/8840 J.POPL 8840 J.POPLE 8840 J.POPLE 8840 J.POPLE 8840 J.POPLE 8840 J.POPLE 8840 J.POPLE 8840 J.POPLE 8840 J.POPLE 8840 J.POPLE 8840 J.POPLE 8840 J.POPLE 8840 J.POPLE 8840 J.POPLE BEAM LINE 2-1 Nov. 28, 2005 Nov. 29, 2005 Nov. 30, 2005 Dec. 01, 2005 Dec. 02, 2005 Dec. 03, 2005 Dec. 04, 2005 MA 8859 B.JOHNSON 8859 B.JOHNSON 8859 B.JOHNSON 8859 B.JOHNSON 8859 B.JOHNSON 8859 B.JOHNSON
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5-4 5-4 Nov. 15, 2010 Nov. 16, 2010 Nov. 17, 2010 Nov. 18, 2010 Nov. 19, 2010 Nov. 20, 2010 Nov. 21, 2010 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU 8820 D.LU BEAM LINE 8-1 Nov. 15, 2010 Nov. 16, 2010 Nov. 17, 2010 Nov. 18, 2010 Nov. 19, 2010 Nov. 20, 2010 Nov. 21, 2010 Unscheduled Unscheduled Unscheduled 3269 S.SUN 3269 S.SUN 3269 S.SUN 3269 S.SUN
The molecular-beam technique has been used in three different experimental arrangements to study a wide range of inter-atomic and molecular forces. Chapter 1 reports results of a low-energy (0.2 kcal/mole) elastic-scattering study of the He-Ar pair potential. The purpose of the study was to accurately characterize the shape of the potential in the well region, by scattering slow He atoms produced by expanding a mixture of He in N/sub 2/ from a cooled nozzle. Chapter 2 contains measurements of the vibrational predissociation spectra and product translational energy for clusters of water, benzene, and ammonia. The experiments show that most of the product energy remains in the internal molecular motions. Chapter 3 presents measurements of the reaction Na + HCl ..-->.. NaCl + H at collision energies of 5.38 and 19.4 kcal/mole. This is the first study to resolve both scattering angle and velocity for the reaction of a short lived (16 nsec) electronic excited state. Descriptions are given of computer programs written to analyze molecular-beam expansions to extract information characterizing their velocity distributions, and to calculate accurate laboratory elastic-scattering differential cross sections accounting for the finite apparatus resolution. Experimental results which attempted to determine the efficiency of optically pumping the Li(2/sup 2/P/sub 3/2/) and Na(3/sup 2/P/sub 3/2/) excited states are given. A simple three-level model for predicting the steady-state fraction of atoms in the excited state is included.
Vernon, M.F.
High gradient lens for charged particle beam
Methods and devices enable shaping of a charged particle beam. A dynamically adjustable electric lens includes a series of alternating a series of alternating layers of insulators and conductors with a hollow center. The series of alternating layers when stacked together form a high gradient insulator (HGI) tube to allow propagation of the charged particle beam through the hollow center of the HGI tube. A plurality of transmission lines are connected to a plurality of sections of the HGI tube, and one or more voltage sources are provided to supply an adjustable voltage value to each transmission line of the plurality of transmission lines. By changing the voltage values supplied to each section of the HGI tube, any desired electric field can be established across the HGI tube. This way various functionalities including focusing, defocusing, acceleration, deceleration, intensity modulation and others can be effectuated on a time varying basis.
Chen, Yu-Jiuan
Laser acceleration of ion beams
We consider methods of charged particle acceleration by means of high-intensity lasers. As an application we discuss a laser booster for heavy ion beams provided, e.g. by the Dubna nuclotron. Simple estimates show that a cascade of crossed laser beams would be necessary to provide additional acceleration to gold ions of the order of GeV/nucleon.
I. A. Egorova; A. V. Filatov; A. V. Prozorkevich; S. A. Smolyansky; D. B. Blaschke; M. Chubaryan
A broad-band beam bunther is disclosed, comprising an evacuated housing, an electron gun therein for producing an electron beam, a buncher cavity having entrance and exit openings through which the beam is directed, grids across such openings, a source providing a positive DC voltage between the cavity and the electron gun, a drift tube through which the electron beam travels in passing through such cavity, grids across the ends of such drift tube, gaps being provided between the drift tube grids and the entrance and exit grids, a modulator for supplying an ultrahigh frequency modulating signal to the drift tube for producing velocity modulation of the electrons in the beam, a drift space in the housing through which the velocity modulated electron beam travels and in which the beam is bunched, and a discharge opening from such drift tube and having a grid across such opening through which the bunched electron beam is discharged into an accelerator or the like. The buncher cavity and the drift tube may be arranged to constitute an extension of a coaxial transmission line which is employed to deliver the modulating signal from a signal source. The extended transmission line may be terminated in its characteristic impedance to afford a broad-
Goldberg, D.A.; Flood, W.S.; Arthur, A.A.; Voelker, F.
Measurements of aperture and beam lifetime using movable beam scrapers in Indus-2 electron storage ring
In this paper, the measurements of vertical and horizontal aperture which are available for stable beam motion in Indus-2 at beam energy 2.5 GeV using movable beam scrapers are presented. These beam scrapers are installed in one of the long straight sections in the ring. With the movement of beam scrapers towards the beam centre, the beam lifetime is measured. The beam lifetime data obtained from the movement of vertical and horizontal beam scrapers are analyzed. The contribution of beam loss due to beam-gas scattering (vacuum lifetime) and electron-electron scattering within a beam bunch (Touschek lifetime) is separated from the measured beam lifetime at different positions of the beam scrapers. Vertical and horizontal beam sizes at scrapers location are estimated from the scraper movement towards the beam centre in quantum lifetime limit and their values closely agree with measured value obtained using X-ray diagnostic beamline.
Kumar, Pradeep; Ghodke, A. D.; Karnewar, A. K.; Holikatti, A. C.; Yadav, S.; Puntambekar, T. A.; Singh, G. [Raja Ramanna Centre for Advanced Technology, Indore 452013 (India)] [Raja Ramanna Centre for Advanced Technology, Indore 452013 (India); Singh, P. [Bhabha Atomic Research Centre, Mumbai (India)] [Bhabha Atomic Research Centre, Mumbai (India)
Beam Head Erosion in Self-Ionized Plasma Wakefield Accelerators
In the recent plasma wakefield accelerator experiments at SLAC, the energy of the particles in the tail of the 42 GeV electron beam were doubled in less than one meter [1]. Simulations suggest that the acceleration length was limited by a new phenomenon--beam head erosion in self-ionized plasmas. In vacuum, a particle beam expands transversely in a distance given by {beta}*. In the blowout regime of a plasma wakefield [2], the majority of the beam is focused by the ion channel, while the beam head slowly spreads since it takes a finite time for the ion channel to form. It is observed that in self-ionized plasmas, the head spreading is exacerbated compared to that in pre-ionized plasmas, causing the ionization front to move backward (erode). A simple theoretical model is used to estimate the upper limit of the erosion rate for a bi-gaussian beam by assuming free expansion of the beam head before the ionization front. Comparison with simulations suggests that half this maximum value can serve as an estimate for the erosion rate. Critical parameters to the erosion rate are discussed.
Berry, M.K.; Blumenfeld, I.; Decker, F.J.; Hogan, M.J.; Ischebeck, R.; Iverson, R.H.; Kirby, N.A.; Siemann, Robert H.; Walz, D.R.; /SLAC; Clayton, C.E.; Huang, C.; Joshi, C.; Lu, W.; Marsh, K.A.; Mori, W.B.; Zhou, M.; /UCLA; Katsouleas, T.C.; Muggli, P.; Oz, E.; /Southern California U.
Single Crystal Diamond Beam Position Monitors with Radiofrequency Electronic Readout
Over the energy range 5{approx}30 keV a suitably contacted, thin ({approx}100 {mu}m) diamond plate can be operated in situ as a continuous monitor of X-ray beam intensity and position as the diamond absorbs only a small percentage of the incident beam. Single crystal diamond is a completely homogeneous material showing fast (ns), spatially uniform signal response and negligible (
Solar, B.; Graafsma, H.; Potdevin, G.; Trunk, U. [Hasylab, Deutsches Elektronen Synchroton, Hamburg (Germany); Morse, J.; Salome, M. [Instrumentation Services and Development Division, European Synchroton Radiation Facility, Grenoble (France)
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Ion Beam Manufacture of Microscale Ion Beam Manufacture of Microscale Tools and Components Manufacturing Technologies Sandia Manufacturing Science &Technology's Focused Ion Beam (FIB) laboratory provides an opportunity for research, development and prototyping. Currently, our scientists are devel- oping methods for ion beam sculpting microscale tools, components and devices. This includes shaping of specialty tools such as end-mills, turning tools and indenters. Many of these have been used in ultra-precision machining DOE applications. Additionally, staff are developing the capability to ion mill geo- metrically-complex features and substrates. This includes the ability to sputter predeter- mined curved shapes of various symmetries and periodicities. Capabilities and Expertise * Two custom-built focused ion beam sys-
Systems for controlling the intensity variations in a laser beam and for frequency conversion thereof
In order to control the intensity of a laser beam so that its intensity varies uniformly and provides uniform illumination of a target, such as a laser fusion target, a broad bandwidth laser pulse is spectrally dispersed spatially so that the frequency components thereof are spread apart. A disperser (grating) provides an output beam which varies spatially in wavelength in at least one direction transverse to the direction of propagation of the beam. Temporal spread (time delay) across the beam is corrected by using a phase delay device (a time delay compensation echelon). The dispersed beam may be amplified with laser amplifiers and frequency converted (doubled, tripled or quadrupled in frequency) with nonlinear optical elements (birefringent crystals). The spectral variation across the beam is compensated by varying the angle of incidence on one of the crystals with respect to the crystal optical axis utilizing a lens which diverges the beam. Another lens after the frequency converter may be used to recollimate the beam. The frequency converted beam is recombined so that portions of different frequency interfere and, unlike interference between waves of the same wavelength, there results an intensity pattern with rapid temoral oscillations which average out rapidly in time thereby producing uniform illumination on target. A distributed phase plate (also known as a random phase mask), through which the spectrally dispersed beam is passed and then focused on a target, is used to provide the interference pattern which becomes nearly modulation free and uniform in intensity in the direction of the spectral variation.
Skupsky, Stanley (Rochester, NY); Craxton, R. Stephen (Rochester, NY); Soures, John (Pittsford, NY)
Expanded beam deflection method for simultaneous measurement of displacement and vibrations of multiple microcantilevers
Here we present an extension of optical beam deflection (OBD) method for measuring displacement and vibrations of an array of microcantilevers. Instead of focusing on the cantilever, the optical beam is either focused above or below the cantilever array, or focused only in the axis parallel to the cantilevers length, allowing a wide optical line to span multiple cantilevers in the array. Each cantilever reflects a part of the incident beam, which is then directed onto a photodiode array detector in a manner allowing distinguishing between individual beams. Each part of reflected beam behaves like a single beam of roughly the same divergence angle in the bending sensing axis as the incident beam. Since sensitivity of the OBD method depends on the divergence angle of deflected beam, high sensitivity is preserved in proposed expanded beam deflection (EBD) method. At the detector, each spot's position is measured at the same time, without time multiplexing of light sources. This provides real simultaneous readout of entire array, unavailable in most of competitive methods, and thus increases time resolution of the measurement. Expanded beam can also span another line of cantilevers allowing monitoring of specially designed two-dimensional arrays. In this paper, we present first results of application of EBD method to cantilever sensors. We show how thermal noise resolution can be easily achieved and combined with thermal noise based resonance frequency measurement.
Nieradka, K.; MaloziePc, G.; Kopiec, D.; Gotszalk, T. [Faculty of Microsystem Electronics and Photonics, Wroclaw University of Technology, Janiszewskiego 11/17, Wroclaw 50-372 (Poland); Grabiec, P.; Janus, P.; Sierakowski, A. [Division of Silicon Microsystem and Nanostructure Technology, Institute of Electron Technology, Lotnikow 32/46, Warsaw 02-668 (Poland)
Conventional Positron Target for a Tesla Formatted Beam
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3 3 SLAC-TN-03-072 November 2003 Abstract This note documents a set of expressions used to explore the issue of whether or not it is reasonable to consider a conventional positron source for a Tesla formatted beam. The critical issue is that of energy deposition in the conversion target and the comparison of the induced stress with the ultimate tensile strength of the target material. Since the length of the incident beam pulse is large in comparison to the ratio of beam size to the speed of sound, the concurrent pressure pulse dissipates in a time short compared to the overall pulse duration and one is left with only the Conventional Positron Target for a Tesla Formatted Beam John C. Sheppard Stanford Linear Accelerator Center
Tomographic determination of the power distribution in electron beams
A tomographic technique for determining the power distribution of an electron beam using electron beam profile data acquired from a modified Faraday cup to create an image of the current density in high and low power beams. A refractory metal disk with a number of radially extending slits is placed above a Faraday cup. The beam is swept in a circular pattern so that its path crosses each slit in a perpendicular manner, thus acquiring all the data needed for a reconstruction in one circular sweep. Also, a single computer is used to generate the signals actuating the sweep, to acquire that data, and to do the reconstruction, thus reducing the time and equipment necessary to complete the process.
Teruya, Alan T. (Livermore, CA); Elmer, John W. (Pleasanton, CA)
Neutrino Beams for Scattering Experiment
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Options for Neutrino Scattering Measurements Options for Neutrino Scattering Measurements Draft Skeleton Table Beam Characteristics K2K CERN AD FNAL Debuncher FNAL Booster NuMI LE NuMI ME NuMI HE Peak E(nu) (GeV) X X ~2.5 1 3.5 7.5 13 Maximum E(nu) (GeV) (->1% peak rate) X X 8.9 3 50 50+ 50+ Nu(mu) CC Rate (per ton-year) X 1.4 0 5,000 210,000 1,100,000 2,000,000 Nubar(mu) CC Rate (per ton-year) X 3.4 ~18 (Time Separated) ~360 (Prompt) 1,000 21,000 32,000 20,000 Nu(e) CC Rate (per ton-year) X 0 0 1 2,300 9,500 12,000 Nubar(e) CC Rate (per ton-year) X 0.4 ~18 (Time Separated) 0.5 630 660 600 Flux uncertainty X X 10% 10% 20% 20% 20% QE events / 100 ton-years X 169 nubar(mu) 47 nu(mu) 17 nubar(e) 525 nubar(e) 500,000 nu(mu) 100,000 nu(mu) X X X Floor space (m**2) X X New Hall New Hall 20 x 2.5 20 x 2.5 20 x 2.5 Run Type X X Parasitic Parasitic Parasitic Parasitic Parasitic
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7-1 7-1 Nov. 15, 2010 Nov. 16, 2010 Nov. 17, 2010 Nov. 18, 2010 Nov. 19, 2010 Nov. 20, 2010 Nov. 21, 2010 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 2B87 I.SEVRIOUKOVA 2B87 I.SEVRIOUKOVA 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ MC CHECKOUT/2B87 2B87 I.SEVRIOUKOVA 2B87 I.SEVRIOUKOVA 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 8845 A.GONZALEZ 2B87 I.SEVRIOUKOVA 2B87 I.SEVRIOUKOVA 2B87 I.SEVRIOUKOVA BEAM LINE 9-1 Nov. 15, 2010 Nov. 16, 2010 Nov. 17, 2010 Nov. 18, 2010 Nov. 19, 2010 Nov. 20, 2010 Nov. 21, 2010 8866 T.DOUKOV 8866 T.DOUKOV 8866 T.DOUKOV 8866 T.DOUKOV 8866 T.DOUKOV FACI FACI
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Feb. 14, 2005 Feb. 21, 2005 Feb. 28, 2005 Mar. 07, 2005 Feb. 14, 2005 Feb. 21, 2005 Feb. 28, 2005 Mar. 07, 2005 Mar. 14, 2005 Mar. 21, 2005 Mar. 28, 2005 Apr. 04, 2005 Apr. 11, 2005 Apr. 18, 2005 Apr. 25, 2005 May 02, 2005 May 09, 2005 May 16, 2005 May 23, 2005 May 30, 2005 Jun. 06, 2005 Jun. 13, 2005 Jun. 20, 2005 Jun. 27, 2005 Jul. 04, 2005 Jul. 11, 2005 Jul. 18, 2005 Jul. 25, 2005 Aug. 01, 2005 Back to Table of Contents WEEK OF Feb. 14, 2005 Feb. 14, 2005 Feb. 15, 2005 Feb. 16, 2005 Feb. 17, 2005 Feb. 18, 2005 Feb. 19, 2005 Feb. 20, 2005 BEAM LINE 1-5 Feb. 14, 2005 Feb. 15, 2005 Feb. 16, 2005 Feb. 17, 2005 Feb. 18, 2005 Feb. 19, 2005 Feb. 20, 2005 8858 D.HARRINGTON 8858 D.HARRIN/DOWN 8858 D.HARRINGTON 8858 D.HARRINGTON 8858 D.HARRINGTON 8858 D.HARRINGTON 8858 D.HARRINGTON
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1, 2013 Nov. 18, 2013 Nov. 25, 2013 Dec. 02, 2013 1, 2013 Nov. 18, 2013 Nov. 25, 2013 Dec. 02, 2013 Dec. 09, 2013 Dec. 16, 2013 Dec. 23, 2013 Dec. 30, 2013 Jan. 06, 2014 Jan. 13, 2014 Jan. 20, 2014 Jan. 27, 2014 Feb. 03, 2014 Feb. 10, 2014 Feb. 17, 2014 Feb. 24, 2014 Back to Table of Contents WEEK OF Nov. 11, 2013 Nov. 11, 2013 Nov. 12, 2013 Nov. 13, 2013 Nov. 14, 2013 Nov. 15, 2013 Nov. 16, 2013 Nov. 17, 2013 BEAM LINE 7-1 Nov. 11, 2013 Nov. 12, 2013 Nov. 13, 2013 Nov. 14, 2013 Nov. 15, 2013 Nov. 16, 2013 Nov. 17, 2013 8803 C.Smith 8803 C.Smith 8803 C.Smith 8803 C.Smith 8803 C.Smith 4B02 A.Yeh 8050 C.Smith 8803 C.Smith 8803 C.Smith 8803 C.Smith 8803 C.Smith Unscheduled MC CHECKOUT/8050 8050 C.Smith
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7-1 7-1 Oct. 26, 2009 Oct. 27, 2009 Oct. 28, 2009 Oct. 29, 2009 Oct. 30, 2009 Oct. 31, 2009 Nov. 01, 2009 CHANGE/8803* C.SMI 8803* C.SMITH 8803* C.SMITH 8803* C.SMITH 8803* C.SMITH 8803* C.SMITH 8803* C.SMITH 8803* C.SMITH 8803* C.SMITH 8803* C.SMITH 8803* C.SMITH 8803* C.SMITH 8803* C.SMITH 8803* C.SMITH 8803* C.SMITH 8803* C.SMITH 8803* C.SMITH 8803* C.SMITH 8803* C.SMITH 8803* C.SMITH 8803* C.SMITH BEAM LINE 9-1 Oct. 26, 2009 Oct. 27, 2009 Oct. 28, 2009 Oct. 29, 2009 Oct. 30, 2009 Oct. 31, 2009 Nov. 01, 2009 CHANGE/8861* I.MAT 8861* I.MATHEWS 8861* I.MATHEWS 8861* I.MATHEWS 8861* I.MATHEWS 8861* I.MATHEWS 8861* I.MATHEWS
Molecular Beam Epitaxy, Multi-source | EMSL
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beam epitaxy, is examined using a combination... Self-corrected Sensors Based On Atomic Absorption Spectroscopy For Atom Flux Measurements In Molecular Beam Epitaxy. A...
Probing Organic Transistors with Infrared Beams
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Probing Organic Transistors with Infrared Beams Probing Organic Transistors with Infrared Beams Print Wednesday, 26 July 2006 00:00 Silicon-based transistors are well-understood,...
Electron beam machining using rotating and shaped beam power distribution
An apparatus and method for electron beam (EB) machining (drilling, cutting and welding) that uses conventional EB guns, power supplies, and welding machine technology without the need for fast bias pulsing technology. The invention involves a magnetic lensing (EB optics) system and electronic controls to: 1) concurrently bend, focus, shape, scan, and rotate the beam to protect the EB gun and to create a desired effective power-density distribution, and 2) rotate or scan this shaped beam in a controlled way. The shaped beam power-density distribution can be measured using a tomographic imaging system. For example, the EB apparatus of this invention has the ability to drill holes in metal having a diameter up to 1000 .mu.m (1 mm or larger), compared to the 250 .mu.m diameter of laser drilling.
Elmer, John W. (Pleasanton, CA); O'Brien, Dennis W. (Livermore, CA)
Alight a beam and beaming light: A theme with variations
The interaction of light (coherent and incoherent) with charged particle beams is explored in various configurations: incoherent scattering of coherent light (laser) from an incoherent particle beam (high temperature), coherent scattering of coherent light (laser) from a {open_quotes}cold{close_quotes} (bunched) beam, femtosecond generation of particle and light beams via {open_quotes}optical slicing{close_quotes} and Thomson/Compton scattering techniques, etc. The domains of ultrashort temporal duration (femtoseconds) as well as ultrashort wavelengths (x rays and shorter), with varying degrees of coherence, are explored. The relevance to a few critical areas of research in the natural sciences, e.g., ultrafast material, chemical and biological processes, protein folding, particle phase space cooling, etc. are touched upon. All the processes discussed involve proper interpretation and understanding of coherent states of matter and radiation, as well as the quality and quantity of information and energy embedded in them. {copyright} {ital 1998 American Institute of Physics.}
Chattopadhyay, S. [Ernest Orlando Lawrence Berkeley National Laboratory, University of California, Berkeley, California94720 (United States)] [Ernest Orlando Lawrence Berkeley National Laboratory, University of California, Berkeley, California94720 (United States)
Electron beam machining using rotating and shaped beam power distribution
An apparatus and method are disclosed for electron beam (EB) machining (drilling, cutting and welding) that uses conventional EB guns, power supplies, and welding machine technology without the need for fast bias pulsing technology. The invention involves a magnetic lensing (EB optics) system and electronic controls to: (1) concurrently bend, focus, shape, scan, and rotate the beam to protect the EB gun and to create a desired effective power-density distribution, and (2) rotate or scan this shaped beam in a controlled way. The shaped beam power-density distribution can be measured using a tomographic imaging system. For example, the EB apparatus of this invention has the ability to drill holes in metal having a diameter up to 1,000 {micro}m (1 mm or larger), compared to the 250 {micro}m diameter of laser drilling. 5 figs.
Elmer, J.W.; O`Brien, D.W.
Diagnostic beam absorber in Mu2e beam line
Star density, hadron flux, and residual dose distributions are calculated around the {mu}2e diagnostic beam absorber. Corresponding surface and ground water activation, and air activation are presented as well.
Rakhno, Igor; /Fermilab
Implementation of a Direct Link between the LHC Beam Interlock System and the LHC Beam Dumping System Re-Triggering Lines
To avoid damage of accelerator equipment due to impacting beam, the controlled removal of the LHC beams from the collider rings towards the dump blocks must be guaranteed at all times. When a beam dump is demanded, the Beam Interlock System communicates this request to the Trigger Synchronisation and Distribution System of the LHC Beam Dumping System. Both systems were built according to high reliability standards. To further reduce the risk of incapability to dump the beams in case of correlated failures in the Trigger Synchronisation and Distribution System, a new direct link from the Beam Interlock System to the re-triggering lines of the LHC Beam Dumping System will be implemented for the start-up with beam in 2015. The link represents a diverse redundancy to the current implementation, which should neither significantly increase the risk for so-called asynchronous beam dumps nor compromise machine availability. This paper describes the implementation choices of this link. Furthermore the results of a rel...
Gabourin, S; Denz, R; Magnin, N; Uythoven, J; Wollmann, D; Zerlauth, M; Vatansever, V; Bartholdt, M; Bertsche, B; Zeiler, P
Electron Cloud in Steel Beam Pipe vs Titanium Nitride Coated and Amorphous Carbon Coated Beam Pipes in Fermilab's Main Injector
This paper documents the use of four retarding field analyzers (RFAs) to measure electron cloud signals created in Fermilab�s Main Injector during 120 GeV operations. The first data set was taken from September 11, 2009 to July 4, 2010. This data set is used to compare two different types of beam pipe that were installed in the accelerator. Two RFAs were installed in a normal steel beam pipe like the rest of the Main Injector while another two were installed in a one meter section of beam pipe that was coated on the inside with titanium nitride (TiN). A second data run started on August 23, 2010 and ended on January 10, 2011 when Main Injector beam intensities were reduced thus eliminating the electron cloud. This second run uses the same RFA setup but the TiN coated beam pipe was replaced by a one meter section coated with amorphous carbon (aC). This section of beam pipe was provided by CERN in an effort to better understand how an aC coating will perform over time in an accelerator. The research consists of three basic parts: (a) continuously monitoring the conditioning of the three different types of beam pipe over both time and absorbed electrons (b) measurement of the characteristics of the surrounding magnetic fields in the Main Injector in order to better relate actual data observed in the Main Injector with that of simulations (c) measurement of the energy spectrum of the electron cloud signals using retarding field analyzers in all three types of beam pipe.
Backfish, Michael
Reflective echo tomographic imaging using acoustic beams
An inspection system includes a plurality of acoustic beamformers, where each of the plurality of acoustic beamformers including a plurality of acoustic transmitter elements. The system also includes at least one controller configured for causing each of the plurality of acoustic beamformers to generate an acoustic beam directed to a point in a volume of interest during a first time. Based on a reflected wave intensity detected at a plurality of acoustic receiver elements, an image of the volume of interest can be generated.
Kisner, Roger; Santos-Villalobos, Hector J
Optical Beam Timing Monitor Experiments at the Advanced Light Source
compensated fiber TT>- -T BPM (Z~ Fig.2. Experimental setuplocked Laser E.O. Mod. BPM Scope PD Fig.4. Block diagram ofpossible bandwidth out of our BPM's. INITIAL E X P E R I M E
Byrd, John; De Santis, Stefano; Wilcox, Rusell; Yan, Yin
The Beam | Open Energy Information
Zip: 2446 Product: The Beam is a start-up company that looks to establish an online retail portal that would market and sell clean energy-related products to consumers....
Problems associated with bunched beam stochastic cooling are reviewed. A longitudinal stochastic cooling system for RHIC is under construction and has been partially commissioned. The state of the system and future plans are discussed.
This report contains the following information on the center for beam physics: Facilities; Organizational Chart; Roster; Profiles of Staff; Affiliates; Center Publications (1991--1993); and 1992 Summary of Activities.
Not Available
Neutron beam testing of triblades
PowerXCell 8i processors and Opterons in four IBM Triblades were tested at LANSCE. The hazard rate when the beam was aimed at the Opterons was higher than when it was aimed at the Cell processors.
Michalak, Sarah E [Los Alamos National Laboratory; Du Bois, Andrew J [Los Alamos National Laboratory; Storlie, Curtis B [Los Alamos National Laboratory; Rust, William N [Los Alamos National Laboratory; Du Bois, David H [Los Alamos National Laboratory; Modl, David G [Los Alamos National Laboratory; Quinn, Heather M [Los Alamos National Laboratory; Blanchard, Sean P [Los Alamos National Laboratory; Manuzzato, Andrea [UNIV DEGLI STUDI DI PADOVA ITALY
Neon Ion Beam Lithography (NIBL)
Existing techniques for electron- and ion-beam lithography, routinely employed for nanoscale device fabrication and mask/mold prototyping, do not simultaneously achieve efficient (low fluence) exposure and high resolution. ...
Winston, Donald
When the electromagnetic fields that are excited by the passage of a bundle of charged particles persist to act upon bunches that follow, then the motions of the bunches are coupled. This action between bunches circulating on a closed orbit can generate growing patterns of bunch excursions. Such growth can often be suppressed by feedback systems that detect the excursion and apply corrective forces to the bunches. To be addressed herein is feedback that acts on motions of the bunch body centers. In addition to being useful for suppressing the spontaneous growth of coupled-bunch motions, such feedback can be used to damp transients in bunches injected into an accelerator or storage ring; for hadrons which lack strong radiation damping, feedback is needed to avoid emittance growth through decoherence. Motions excited by noise in magnetic fields or accelerating rf can also be reduced by using this feedback. Whether the action is on motions that are transverse to the closed orbit or longitudinal, the arrangement is the same. Bunch position is detected by a pickup and that signal is processed and directed to a kicker that may act upon the same bunch or some other portion of the collective beam pattern. Transverse motion is an oscillation with angular frequency {nu}{perpendicular}{omega}{sub o} where {omega}{sub o} is the orbital frequency 2{pi}{line_integral}o. Longitudinal synchrotron oscillation occurs at frequency {omega} {sub s} = {nu}{sub s}{omega}{sub o}. The former is much more rapid, {nu}{perpendicular} being on the order of 10 while {nu}{sub s} is typically about 10{sup minus 1} to 10 {sup minus 2}.
Lambertson, G.
Compact time-of-flight mass spectrometer
This paper describes a time-of-flight mass spectrometer developed for measuring the parameters of a pulsed hydrogen beam. The duration of an electron-beam current pulse in the ionizer of the mass spectrometer can be varied within 2-20 usec, the pulse electron current is 0.6 mA, and the electron energy is 250 eV. The time resolution of the mass spectrometer is determined by the repetition period of the electron-beam current pulses and is 40 usec. The mass spectrometer has 100% transmission in the direction of motion of molecular-beam particles. The dimension of the mass spectrometer is 7 cm in this direction. The mass resolution is sufficient for determination of the composition of the hydrogen beam.
Belov, A.S.; Kubalov, S.A.; Kuzik, V.F.; Yakushev, V.P.
Electron Beam Alignment Strategy in the LCLS Undulators
The x-ray FEL process puts very tight tolerances on the straightness of the electron beam trajectory (2 {micro}m rms) through the LCLS undulator system. Tight but less stringent tolerances of 80 {micro}m rms vertical and 140 {micro}m rms horizontally are to be met for the placement of the individual undulator segments with respect to the beam axis. The tolerances for electron beam straightness can only be met through beam-based alignment (BBA) based on electron energy variations. Conventional alignment will set the start conditions for BBA. Precision-fiducialization of components mounted on remotely adjustable girders and the use of beam-finder wires (BFW) will satisfy placement tolerances. Girder movement due to ground motion and temperature changes will be monitored continuously by an alignment monitoring system (ADS) and remotely corrected. This stabilization of components as well as the monitoring and correction of the electron beam trajectory based on BPMs and correctors will increase the time between BBA applications. Undulator segments will be periodically removed from the undulator Hall and measured to monitor radiation damage and other effects that might degrade undulator tuning.
Nuhn, H.-D.; Emma, P.J.; Gassner, G.L.; LeCocq, C.M.; Peters, E.; Ruland, R.E.; /SLAC
Spectral evolution in an electron beam pumped XeF laser
A spectral sweep in the 353-nm band of an electron beam pumped XeF laser has been investigated. The time-integrated lasing spectra broaden as the pulse length, electron beam pump rate, and intracavity flux are increased. Several possible explanations are discussed.
Harris, D.G.; Burde, D.H.; Malins, R.J.; Tillotson, J.H.
Beam dynamics in accelerators for medical applications: from calculations to machine performance
Beam dynamics in accelerators for medical applications: from calculations to machine performance S, z', W, RF-phase) at each time-moment for each particle in the accelerating bunch use cylindrical, Novosibirsk, Russian Federation #12;Main results of calculations 6 ...transverse beam size during acceleration
Controlled oxygen doping of GaN using plasma assisted molecular-beam epitaxy
Controlled oxygen doping of GaN using plasma assisted molecular-beam epitaxy A. J. Ptak, L. J-assisted molecular-beam epitaxy to study the dependence of oxygen incorporation on polarity and oxygen partial pressure. Oxygen incorporates at a rate ten times faster on nitrogen-polar GaN than on the Ga polarity
Myers, Tom
H-Mode Accelerating Structures with PMQ Beam Focusing
We have developed high-efficiency normal-conducting RF accelerating structures by combining H-mode resonator cavities and a transverse beam focusing by permanent-magnet quadrupoles (PMQ), for beam velocities in the range of a few percent of the speed of light. The shunt impedance of inter-digital H-mode (IH-PMQ) structures is 10-20 times higher than that of a conventional drift-tube linac, while the transverse size is 4-5 times smaller. Results of the combined 3-D modeling - electromagnetic computations, multi-particle beam-dynamics simulations with high currents, and thermal-stress analysis - for an IH-PMQ accelerator tank are presented. The accelerating field profile in the tank is tuned to provide the best propagation of a 50-mA deuteron beam using coupled iterations of electromagnetic and beam-dynamics modeling. Measurements of a cold model of the IH-PMQ tank show a good agreement with the calculations. H-PMQ accelerating structures following a short RFQ can be used both in the front end of ion linacs or ...
Kurennoy, Sergey S; O'Hara, James F; Olivas, Eric R; Wangler, Thomas P
Large area electron beam pumped krypton fluoride laser amplifier
Nike is a recently completed multi-kilojoule krypton fluoride (KrF) laser that has been built to study the physics of direct drive inertial confinement fusion. This paper describes in detail both the pulsed power and optical performance of the largest amplifier in the Nike laser, the 60 cm amplifier. This is a double pass, double sided, electron beam-pumped system that amplifies the laser beam from an input of 50 J to an output of up to 5 kJ. It has an optical aperture of 60 cm {times} 60 cm and a gain length of 200 cm. The two electron beams are 60 cm high {times} 200 cm wide, have a voltage of 640 kV, a current of 540 kA, and a flat top power pulse duration of 250 ns. A 2 kG magnetic field is used to guide the beams and prevent self-pinching. Each electron beam is produced by its own Marx/pulse forming line system. The amplifier has been fully integrated into the Nike system and is used on a daily basis for laser-target experiments. {copyright} {ital 1997 American Institute of Physics.}
Sethian, J.D.; Obenschain, S.P.; Gerber, K.A.; Pawley, C.J.; Serlin, V.; Sullivan, C.A. [Plasma Physics Division, Naval Research Laboratory, Washington DC 20375 (United States)] [Plasma Physics Division, Naval Research Laboratory, Washington DC 20375 (United States); Webster, W. [Research Support Instruments, 4325-B Forbes Boulevard, Lanham, Maryland 20706 (United States)] [Research Support Instruments, 4325-B Forbes Boulevard, Lanham, Maryland 20706 (United States); Deniz, A.V.; Lehecka, T. [Science Applications International Corporation, 1710 Goodridge Drive, McLean, Virginia 22102 (United States)] [Science Applications International Corporation, 1710 Goodridge Drive, McLean, Virginia 22102 (United States); McGeoch, M.W. [PLEX Corporation, 21 Addington Road, Brookline, Massachusetts 02146 (United States)] [PLEX Corporation, 21 Addington Road, Brookline, Massachusetts 02146 (United States); Altes, R.A.; Corcoran, P.A.; Smith, I.D. [Pulse Sciences, Incorporated, 600 McCormick Street, San Leandro, California 94577 (United States)] [Pulse Sciences, Incorporated, 600 McCormick Street, San Leandro, California 94577 (United States); Barr, O.C. [Pharos Technical Enterprises, 1603 Barcelona Street, Livermore, California 94550 (United States)] [Pharos Technical Enterprises, 1603 Barcelona Street, Livermore, California 94550 (United States)
A Timoshenko beam theory with pressure corrections for layered orthotropic beams
A Timoshenko beam theory with pressure corrections for layered orthotropic beams Graeme J. Kennedya of Michigan, Ann Arbor, MI 48109, USA Abstract A Timoshenko beam theory for layered orthotropic beams and rotation variables that provide the kinematic description of the beam, stress and strain moments used
Papalambros, Panos
Physics Reach of the Beta Beam
Beta Beams are designed to produce pure (anti)electron neutrino beams and could be an elegant and powerful option for the search of leptonic CP violating processes. In this paper will be quantified the physics reach of a CERN based Beta Beam and of a Super Beam - Beta Beam combination. The CP phase $\\delta$ sensitivity results to be comparable to a Neutrino Factory for $\\sin^2{\\theta_{13}}$ values greater than $10^{-4}$.
Mauro Mezzetto
Machine and Beam Delivery Updates
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MAchine and Beam delivery Updates FY13 MAchine and Beam delivery Updates FY13 Summary of Beam Delivery: FACET Summary Feb_15_22.pdf FACET Summary Feb_15_22.pdf FACET Summary Feb_23_Mar_1.pdf FACET Summary Feb_23_Mar_1.pdf FACET Summary Mar_2_8.pdf FACET Summary Mar_2_8.pdf FACET Summary Mar_9_15.pdf FACET Summary Mar_9_15.pdf FACET Summary Mar_16_22.pdf FACET Summary Mar_16_22.pdf FACET Summary Mar_23_29.pdf FACET Summary Mar_23_29.pdf FACET Summary Mar_30_Apr_5.pdf FACET Summary Mar_30_Apr_5.pdf FACET Summary Apr_6_12.pdf FACET Summary Apr_6_12.pdf FACET Summary Apr_27_May_3.pdf FACET Summary Apr_27_May_3.pdf FACET Summary May_4_10.pdf FACET Summary May_4_10.pdf Emittance Stability in Sector 2_31513.pdf Emittance Stability in Sector 2_31513.pdf FACET beam operations readiness with R56.pdf FACET beam operations readiness with R56.pdf (6/19/2013)
Bunched beam transfer from one accelerator to another requires coordination and synchronization of many ramped devices. During collider operation timing issues are more complicated since one has to switch from proton injection devices to antiproton injection devices. Proton and antiproton transfers are clearly distinct sequences since protons and antiprotons circulate in opposite directions in the Main Ring (MR) and in the Tevatron. The time bumps are different, the kicker firing delays are different, the kickers and lambertson magnets are different, etc. Antiprotons are too precious to be used for tuning purposes, therefore protons are transferred from the Tevatron back into the Main Ring, tracing the path of antiprotons backwards. This tuning operation is called ``reverse injection.`` Previously, the reverse injection was handled in one supercycle. One batch of uncoalesced bunches was injected into the Tevatron and ejected after 40 seconds. Then the orbit closure was performed in the MR. In the new scheme the lambertson magnets have to be moved and separator polarities have to be switched, activities that cannot be completed in one supercycle. Therefore, the reverse injection sequence was changed. This involved the redefinition of TVBS clock event $D8 as MRBS $D8 thus making it possible to inject 6 proton batches (or coalesced bunches) and eject them one at a time on command, performing orbit closure each time in the MR. Injection devices are clock event driven. The TCLK is used as the reference clock. Certain TCLK events are triggered by the MR beam synchronized clock (MRBS) events. Some delays are measured in terms of MRBS ticks and MR revolutions. See Appendix A for a brief description of the beam synchronized clocks.
Saritepe, S.; Annala, G.
The Beam Profile Calculation for Diagnostic Neutral Beam on HT-7 Tokamak
Science Journals Connector (OSTI)
A new calculation method is introduced for convergence beam intensity. The program based on this method is prepared for beam intensity distribution and beam power calculation. Taking the HT-7 DNB as a referenc...
Lizhen Liang; Chundong Hu
Effect of Beam-Beam Interactions on Stability of Coherent Oscillations in a Muon Collider
In order to achieve peak luminosity of a muon collider in the 10{sup 34}/cm{sup 2}/s range the number of muons per bunch should be of the order of a few units of 10{sup 12} rendering the beam-beam parameter as high as 0.1 per IP. Such strong beam-beam interaction can be a source of instability if the working point is chosen close to a coherent beam-beam resonance. On the other hand, the beam-beam tunespread can provide a mechanism of suppression of the beam-wall driven instabilities. In this report the coherent instabilities driven by beam-beam and beam-wall interactions are studied with the help of BBSS code for the case of 1.5 TeV c.o.m muon collider.
Alexahin, Y.; /Fermilab; Ohmi, K.; /KEK, Tsukuba
Survey of Collective Instabilities and Beam-Plasma Interactions in Intense Heavy Ion Beams
H. Qin, Phys. Rev. ST Accel. Beams 4, 104401 (2001). [30] S.Davidson, Phys. Rev. ST Accel. Beams 5, 021001 (2002). [31]Channell, Phys. Rev. ST Accel. Beams 2, 074401 (1999); [32
Davidson, Ronald C.
Neutral-Beam-Heating Results from the Princeton Large Torus
Science Journals Connector (OSTI)
Experimental results from high-power neutral-beam-injection experiments on the Princeton Large Torus tokamak are reported. At the highest beam powers (2.4 MW) and lowest plasma densities [ne(0)=5�1013 cm-3], ion temperatures of 6.5 keV are achieved. The ion collisionality ?i* drops below 0.1 over much of the radial profile. Electron heating of ?TeTe?50% has also been observed, consistent with the gross energy-confinement time of the Ohmically heated plasma, but indicative of enhanced electron-energy confinement in the core of the plasma.
H. Eubank et al.
Nonparaxial Mathieu and Weber accelerating beams
We demonstrate both theoretically and experimentally nonparaxial Mathieu and Weber accelerating beams, generalizing the concept of previously found accelerating beams. We show that such beams bend into large angles along circular, elliptical or parabolic trajectories but still retain nondiffracting and self-healing capabilities. The circular nonparaxial accelerating beams can be considered as a special case of the Mathieu accelerating beams, while an Airy beam is only a special case of the Weber beams at the paraxial limit. Not only generalized nonparaxial accelerating beams open up many possibilities of beam engineering for applications, but the fundamental concept developed here can be applied to other linear wave systems in nature, ranging from electromagnetic and elastic waves to matter waves.
Peng Zhang; Yi Hu; Tongcang Li; Drake Cannan; Xiaobo Yin; Roberto Morandotti; Zhigang Chen; Xiang Zhang
Stochastic cooling of bunched beams
Numerical simulation studies are presented for transverse and longitudinal stochastic cooling of bunched particle beams. Radio frequency buckets of various shapes (e.g. rectangular, parabolic well, single sinusoidal waveform) are used to investigate the enhancement of phase space cooling by nonlinearities of synchrotron motion. The connection between the notions of Landau damping for instabilities and mixing for stochastic cooling are discussed. In particular, the need for synchrotron frequency spread for both Landau damping and good mixing is seen to be comparable for bunched beams.
Bisognano, J.J.; Chattopadhyay, S.
Thermal stresses in laminated beams
24. Normal Stress Distribution for a Cantilever Laminated Beam, T-Z sinzx/L --------------- 58 m. i 25. Axial Stress Distribution for a Cantilever Laminated Bearq, T-T (2z/8+1) 2 mi 27. Normal Stress Distribution for ("/L) ? ---- 6 O 2 a... 80 100 Stress o (psi) xz. i Fig. 14. Normal Stress Distribution for a Simply-Supported Laminated Beam, T=z (2z/H+1) (x/L) 2 2 m. 1 6 4 x Classical Solution o Present Solution Load: Sinusoidal I F 0 100 200 300 400 Stress c (ps&) XX. 1 500...
Marcano, Victor Manuel
Experimental optimization of the 6-dimentional electron beam emittance at the NSLS SDL
Experimental optimization of the 6-dimensional electron beam emittance generated by a Magnesium (Mg) photocathode RF gun is presented in this report. A new electron beam optimization algorithm for a low charge (<100 pC) beam was experimentally demonstrated; where the electron beam velocity bunching inside the RF gun plays a critical role, and the transverse emittance as a function of the laser-RF timing jitter was experimentally characterized for the first time. A 20 pC electron beam was optimized to have a normalized slice emittance of 0.15 mm mrad and a longitudinal projected emittance of 3.9 ps keV. Furthermore, the upper limit of the measured thermal emittance - 0.5 mm mrad per mm of the rms laser size, is about 50% lower than the theoretical prediction for a Mg cathode (Qian et al., 2010) [1].
Qian, H.J.; Murphy, J.; Shen,Y.; Tang,C.X.; Wang,X.J.
Electron beam induced radio emission from ultracool dwarfs
We present the numerical simulations for an electron-beam-driven and loss-cone-driven electron-cyclotron maser (ECM) with different plasma parameters and different magnetic field strengths for a relatively small region and short time-scale in an attempt to interpret the recent discovered intense radio emission from ultracool dwarfs. We find that a large amount of electromagnetic field energy can be effectively released from the beam-driven ECM, which rapidly heats the surrounding plasma. A rapidly developed high-energy tail of electrons in velocity space (resulting from the heating process of the ECM) may produce the radio continuum depending on the initial strength of the external magnetic field and the electron beam current. Both significant linear polarization and circular polarization of electromagnetic waves can be obtained from the simulations. The spectral energy distributions of the simulated radio waves show that harmonics may appear from 10 to 70$\
Yu, S; Kuznetsov, A; Hallinan, G; Antonova, A; MacKinnon, A L; Golden, A
Neutron beam imaging at neutron spectrometers at Dhruva
A low efficiency, 2-Dimensional Position Sensitive Neutron Detector based on delay line position encoding is developed. It is designed to handle beam flux of 10{sup 6}-10{sup 7} n/cm{sup 2}/s and for monitoring intensity profiles of neutron beams. The present detector can be mounted in transmission mode, as the hardware allows maximum neutron transmission in sensitive region. Position resolution of 1.2 mm in X and Y directions, is obtained. Online monitoring of beam images and intensity profile of various neutron scattering spectrometers at Dhruva are presented. It shows better dynamic range of intensity over commercial neutron camera and is also time effective over the traditionally used photographic method.
Desai, Shraddha S.; Rao, Mala N. [Solid State Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)
Acquisition of fast neutron spectra upon possible disruptions of the accelerator beam
Science Journals Connector (OSTI)
The technique for time-of-flight measurements of fast neutron spectra upon possible disruptions of the accelerator beam is presented. The measurement procedure is corrected, the algorithm of functioning of the...
V. G. Demenkov; A. A. Lychagin; P. V. Demenkov�
The laser beam dump is positioned in a housing. An absorbing glass plate means is operatively connected to the housing. A heat sync means for extracting heat from the absorbing glass plate means is operatively connected to the housing and operatively connected to the absorbing glass plate means.
Halpin, John (Tracy, CA)
NLE Websites -- All DOE Office Websites (Extended Search)
Detectors Detectors Detector Response (V/W=V*ps/pJ) Noise Eq. Power (NEP, W/Hz1/2) Wavelength Liquid He Bolometer 2.73E+5 1.87E-13 > 15 um Golay Cell ~1500 @ 10 THz w/15 Hz modulation ~1E-10 0.2 THz to 20 THz (1.5 mm to 15 um) LN2 (blue) cooled HgCdTe >10,000 ~4E-30 2 um to 24 um Te (red) cooled HgCdTe N/A ~2.5E-10 2 um to 9 um Silicon detector for X-ray (PDF) Liquid He Bolometer Manual (PDF) Rapid Scanning Imaging Spectrograph/Monochromator Manual (PDF) Shad-o-snap 1024 X-ray Camera The Shad-o-Snap 1024 x-ray camera is part of the new product line of easy-to-use, "smart" USB cameras developed by Rad-icon Imaging Corp. This microprocessor based camera offers simple timing control combined with new readout modes and easy image transfers as TIFF or raw integer image files.
A combined beta-beam and electron capture neutrino experiment
The next generation of long baseline neutrino experiments will aim at determining the value of the unknown mixing angle, theta_{13}, the type of neutrino mass hierarchy and the presence of CP-violation in the lepton sector. Beta-beams and electron capture experiments have been studied as viable candidates for long baseline experiments. They use a very clean electron neutrino beam from the beta-decays or electron capture decays of boosted ions. In the present article we consider an hybrid setup which combines a beta-beam with an electron capture beam by using boosted Ytterbium ions. We study the sensitivity to the CP-violating phase delta and the theta_{13} angle, the CP-discovery potential and the reach to determine the type of neutrino mass hierarchy for this type of long baseline experiment. The analysis is performed for different neutrino beam energies and baselines. Finally, we also discuss how the results would change if a better knowledge of some of the assumed parameters was achieved by the time this experiment could take place.
J. Bernabeu; C. Espinoza; C. Orme; S. Palomares-Ruiz; S. Pascoli
Enhancing Neutron Beam Production with a Convoluted Moderator
We describe a new concept for a neutron moderating assembly resulting in the more efficient production of slow neutron beams. The Convoluted Moderator, a heterogeneous stack of interleaved moderating material and nearly transparent single-crystal spacers, is a directionally-enhanced neutron beam source, improving beam effectiveness over an angular range comparable to the range accepted by neutron beam lines and guides. We have demonstrated gains of 50% in slow neutron intensity for a given fast neutron production rate while simultaneously reducing the wavelength-dependent emission time dispersion by 25%, both coming from a geometric effect in which the neutron beam lines view a large surface area of moderating material in a relatively small volume. Additionally, we have confirmed a Bragg-enhancement effect arising from coherent scattering within the single-crystal spacers. We have not observed hypothesized refractive effects leading to additional gains at long wavelength. In addition to confirmation of the validity of the Convoluted Moderator concept, our measurements provide a series of benchmark experiments suitable for developing simulation and analysis techniques for practical optimization and eventual implementation at slow neutron source facilities.
Iverson, Erik B [ORNL] [ORNL; Baxter, David V [Center for the Exploration of Energy and Matter, Indiana University] [Center for the Exploration of Energy and Matter, Indiana University; Muhrer, Guenter [Los Alamos National Laboratory (LANL)] [Los Alamos National Laboratory (LANL); Ansell, Stuart [ISIS Facility, Rutherford Appleton Laboratory (ISIS)] [ISIS Facility, Rutherford Appleton Laboratory (ISIS); Gallmeier, Franz X [ORNL] [ORNL; Dalgliesh, Robert [ISIS Facility, Rutherford Appleton Laboratory (ISIS)] [ISIS Facility, Rutherford Appleton Laboratory (ISIS); Lu, Wei [ORNL] [ORNL; Kaiser, Helmut [Center for the Exploration of Energy and Matter, Indiana University] [Center for the Exploration of Energy and Matter, Indiana University
Generation of vector beams with liquid crystal disclination lines
We report that guiding light beams, ranging from continuous beams to femtosecond pulses, along liquid crystal defect lines can transform them into vector beams with various polarization profiles. Using Finite Difference Time Domain numerical solving of Maxwell equations, we confirm that the defect in the orientational order of the liquid crystal induces a defect in the light field with twice the winding number of the liquid crystal defect, coupling the topological invariants of both fields. For example, it is possible to transform uniformly-polarized light into light with a radial polarization profile. Our approach also correctly yields a zero-intensity region near the defect core, which is always present in areas of discontinuous light polarization or phase. Using circularly polarized incident light, we show that defects with non-integer winding numbers can be obtained, where topological constants are preserved by phase vortices, demonstrating coupling between the light's spin, orbital angular momentum and polarization profile. Further, we find an ultrafast femtosecond laser pulse travelling along a defect line splits into multiple intensity regions, again depending on the defect's winding number, allowing applications in beam steering and filtering. Finally, our approach describing generation of complex optical fields via coupling with topological defect lines in optically birefringent nematic fluids can be easily extended to high-intensity beams that affect nematic ordering.
Miha ?an?ula; Miha Ravnik; Slobodan �umer
Laser power beaming applications and technology
Beaming laser energy to spacecraft has important economic potential. It promises significant reduction in the cost of access to space, for commercial and government missions. While the potential payoff is attractive, existing technologies perform the same missions and the keys to market penetration for power beaming are a competitive cost and a schedule consistent with customers` plans. Rocketdyne is considering these questions in the context of a commercial enterprise -- thus, evaluation of the requirements must be done based on market assessments and recognition that significant private funding will be involved. It is in the context of the top level business considerations that the technology requirements are being assessed and the program being designed. These considerations result in the essential elements of the development program. Since the free electron laser is regarded as the ``long pole in the tent``, this paper summarizes Rocketdyne`s approach for a timely, cost-effective program to demonstrate an FEL capable of supporting an initial operating capability (IOC).
Burke, R.J.; Cover, R.A.; Curtin, M.S.; Dinius, R.W.; Lampel, M.C. [Rockwell International Corp., Canoga Park, CA (United States). Rocketdyne Division
X-Band Photoinjector Beam Dynamics
SLAC is studying the feasibility of using an X-band RF photocathode gun to produce low emittance bunches for applications such as a mono-energetic MeV {gamma} ray source (in collaboration with LLNL) and a photoinjector for a compact FEL. Beam dynamics studies are being done for a configuration consisting of a 5.5-cell X-band gun followed by several 53-cell high-gradient X-band accelerator structures. A fully 3D program, ImpactT, is used to track particles taking into account space charge forces, short-range longitudinal and transverse wakefields, and the 3D rf fields in the structures, including the quadrupole component of the couplers. The effect of misalignments of the various elements, including the drive-laser, gun, solenoid and accelerator structures, are evaluated. This paper presents these results and estimates of the expected bunch emittance vs cathode gradient, and the effects of mixing between the fundamental and off-frequency longitudinal modes. An X-band gun at SLAC has been shown to operate reliably with a 200 MV/m acceleration gradient at the cathode, which is nearly twice the 115 MV/m acceleration gradient in the LCLS gun. The higher gradient should roughly balance the space charge related transverse emittance growth for the same bunch charge but provide a 3-4 times shorter bunch length. The shorter length would make the subsequent bunch compression easier and allow for a more effective use of emittance exchange. Such a gun can also be used with an X-band linac to produce a compact FEL or g ray source that would require rf sources of only one frequency for beam generation and acceleration. The feasibility of using an X-band rf photocathode gun and accelerator structures to generate high quality electron beams for compact FELs and g ray sources is being studied at SLAC. Results from the X-band photoinjector beam dynamics studies are reported in this paper.
Zhou, Feng; /SLAC; Adolphsen, Chris; /SLAC; Ding, Yuantao; /SLAC; Li, Zenghai; /SLAC; Vlieks, Arnold; /SLAC
Electron Beam--21st Century Food Technology
This publication explains electron beam irradiation technology to consumers, industry professionals and government officials. Electron beam irradiation is a method of treating food and other products for pathogens that might jeopardize food safety....
Vestal, Andy
Fusion Reactions Involving Radioactive Beams at GANIL
Science Journals Connector (OSTI)
......February 2004 research-article Articles Fusion Reactions Involving Radioactive Beams...been used to produce exotic nuclei via fusion evaporation or to study reaction mechanisms...Physics Supplement No. 154, 2004 113 Fusion Reactions Involving Radioactive Beams......
Gilles de France
Transport of elliptic intense charged -particle beams
The transport theory of high-intensity elliptic charged-particle beams is presented. In particular, the halo formation and beam loss problem associated with the high space charge and small-aperture structure is addressed, ...
Zhou, J. (Jing), 1978-
Adaptive phase measurements for narrowband squeezed beams
We have previously [Phys. Rev. A 65, 043803 (2002)] analyzed adaptive measurements for estimating the continuously varying phase of a coherent beam, and a broadband squeezed beam. A real squeezed beam must have finite photon flux N and hence can be significantly squeezed only over a limited frequency range. In this paper we analyze adaptive phase measurements of this type for a realistic model of a squeezed beam. We show that, provided it is possible to suitably choose the parameters of the beam, a mean-square phase uncertainty scaling as (N/kappa)^{-5/8} is possible, where kappa is the linewidth of the beam resulting from the fluctuating phase. This is an improvement over the (N/kappa)^{-1/2} scaling found previously for coherent beams. In the experimentally realistic case where there is a limit on the maximum squeezing possible, the variance will be reduced below that for coherent beams, though the scaling is unchanged.
Dominic W. Berry; Howard M. Wiseman
MIS-1 electron-beam ion source
Science Journals Connector (OSTI)
The Institute of Nuclear Physics (INP) has developed and produced electron-beam multiply charged ion sources. These ion sources give the electron beam its high density in the ionization...3 A/cm2.... They produce...
V. G. Abdulmanov; N. S. Dikansky
Dose-Response Effect of Charged Carbon Beam on Normal Rat Retina Assessed by Electroretinography
Purpose: To compare the effects of carbon beam irradiation with those of proton beam irradiation on the physiology of the retina of rats. Methods and Materials: Eight-week-old Wister rats were used. The right eyes were irradiated with carbon beam (1, 2, 4, 8, and 16 Gy) or proton beam (4, 8, 16, and 24 Gy) with the rats under general anesthesia. Electroretinograms were recorded 1, 3, 6, and 12 months after the irradiation, and the amplitudes of the a and b waves were compared with those of control rats. Results: The amplitude of b waves was reduced more than that of a waves at lower irradiation doses with both types of irradiation. With carbon ion irradiation, the amplitudes of the b wave were significantly reduced after radiation doses of 8 and 16 Gy at 6 months and by radiation doses of 4, 8, and 16 Gy at 12 months. With proton beam irradiation, the b-wave amplitudes were significantly reduced after 16 and 24 Gy at 6 months and with doses of 8 Gy or greater at 12 months. For the maximum b-wave amplitude, a significant difference was observed in rats irradiated with carbon beams of 4 Gy or more and with proton beams of 8 Gy or more at 12 months after irradiation. Conclusions: These results indicate that carbon beam irradiation is about two times more damaging than proton beam irradiation on the rat retina at the same dose.
Mizota, Atsushi, E-mail: firstname.lastname@example.com [Department of Ophthalmology, Teikyo University School of Medicine, Tokyo (Japan); Department of Ophthalmology, Juntendo University Urayasu Hospital, Urayasu (Japan); Tanaka, Minoru [Department of Ophthalmology, Juntendo University Urayasu Hospital, Urayasu (Japan); Kubota, Mariko; Negishi, Hisanari [Department of Ophthalmology, National Hospital Organization Chiba Medical Center, Chiba (Japan); Watanabe, Emiko [Department of Ophthalmology, Teikyo University School of Medicine, Tokyo (Japan); Tsuji, Hiroshi; Miyahara, Nobuyuki; Furusawa, Yoshiya [National Institute of Radiological Sciences, Chiba (Japan)
Beam interaction measurements with a Retarding Field Analyzer in a high-current high-vacuum positively charged particle accelerator
Science Journals Connector (OSTI)
A Retarding Field Analyzer (RFA) was inserted in a drift region of the magnetic transport section of the High-Current Experiment (HCX), that is at high-vacuum, to measure ions and electrons resulting from beam interaction with background gas and walls. The ions are expelled during the beam pulse by the space�charge potential and the electrons are expelled mainly at the end of the beam, when the beam potential decays. The ion energy distribution shows the beam potential of ? 2100 V and the beam�background gas total cross-section of 3.1 � 10 - 19 m 2 . The electron energy distribution reveals that the expelled electrons are mainly desorbed from the walls and gain ? 22 eV from the beam potential decaying with time before entering the RFA. Details of the RFA design and of the measured energy distributions are presented and discussed.
M. Kireeff Covo; A.W. Molvik; A. Friedman; J.J. Barnard; P.A. Seidl; B.G. Logan; D. Baca; J.L. Vujic
Commissioning of Photon Beams of a Flattening Filter-Free Linear Accelerator and the Accuracy of Beam Modeling Using an Anisotropic Analytical Algorithm;TrueBeam; Flattening filter free; Commissioning; Anisotropic analytical algorithm
Purpose: To investigate dosimetric characteristics of a new linear accelerator designed to deliver flattened, as well as flattening filter-free (FFF), beams. To evaluate the accuracy of beam modeling under physical conditions using an anisotropic analytical algorithm. Methods and Materials: Dosimetric data including depth dose curves, profiles, surface dose, penumbra, out-of-field dose, output, total and scatter factors were examined for four beams (X6, X6FFF, X10, and X10FFF) of Varian's TrueBeam machine. Beams modeled by anisotropic analytical algorithm were compared with measured dataset. Results: FFF beams have lower mean energy (tissue-phantom ratio at the depths of 20 and 10 cm (TPR 20/10): X6, 0.667; X6FFF, 0.631; X10, 0.738; X10FFF, 0.692); maximum dose is located closer to the surface; and surface dose increases by 10%. FFF profiles have sharper but faster diverging penumbra. For small fields and shallow depths, dose outside a field is lower for FFF beams; however, the advantage fades with increasing phantom scatter. Output increases 2.26 times for X6FFF and 4.03 times for X10FFF and is less variable with field size; collimator exchange effect is reduced. A good agreement between modeled and measured data is observed. Criteria of 2% depth-dose and 2-mm distance-to-agreement are always met. Conclusion: Reference dosimetric characteristics of TrueBeam photon bundles were obtained, and successful modeling of the beams was achieved.
Hrbacek, Jan, E-mail: firstname.lastname@example.com [Department of Radiation Oncology, University Hospital Zuerich, Zuerich (Switzerland); Lang, Stephanie; Kloeck, Stephan [Department of Radiation Oncology, University Hospital Zuerich, Zuerich (Switzerland)
Physics with energetic radioactive ion beams
Beams of short-lived, unstable nuclei have opened new dimensions in studies of nuclear structure and reactions. Such beams also provide key information on reactions that take place in our sun and other stars. Status and prospects of the physics with energetic radioactive beams are summarized.
Henning, W.F.
Cyclotrons for the production of radioactive beams
This paper describes the characteristics and design choices for modern cyclotrons. Cyclotrons can be used in 3 areas in the radioactive beam field: the production of high energy heavy ion beams for use in fragmentation, the spallation of targets with high energy protons, and the acceleration of radioactive beams from low energy to the MeV/u range. 16 refs., 6 figs.
Clark, D.J.
Beam Dynamics and Instabilities in MEIC Design
In this paper, we study the narrow and broadband impedance calculations and various instabilities generated by single and multiple bunches. We study the physical phenomena such as intra-beam scattering, touschek scattering, beam-gas scattering, ion trapping and fast beam-ion instability, etc. Details will be discussed in the paper.
S. Ahmed, G.A. Krafft, B.C. Yunn
Gaussian beams in inhomogeneous anisotropic layered structures
Gaussian beams in inhomogeneous anisotropic layered structures Vlastislav Cerven´y 1 ) and email@example.com. Summary Gaussian beams concentrated close to rays of high-frequency seismic body waves prop- agating in an inhomogeneous anisotropic layered structure are studied. The amplitude profiles of the Gaussian beam along
Cerveny, Vlastislav
A Generalized Vlasov Theory for Composite Beams
A Generalized Vlasov Theory for Composite Beams Wenbin Yu, Department of Mechanical and Aerospace-0150 Abstract A generalized Vlasov theory for composite beams with arbitrary geometric and material sectional properties is developed based on the variational asymptotic beam sectional analysis. Instead of invoking ad
Yu, Wenbin
Stability design of long precast concrete beams
Stability design of long precast concrete beams T. J. Stratford, BA, MEng, C. J. Burgoyne BA, MSc needed for design engineers to check the stability of precast concrete beams when simply supported loads can be determined and how estimates can be made of the eect of imperfections both in the beam
Burgoyne, Chris
Lateral stability of long precast concrete beams
Lateral stability of long precast concrete beams T. J. Stratford, BA, BEng, and C. J. Burgoyne, BA, MSc, CEng, MICE & Modern precast concrete bridge beams are becoming increasingly long and slender, making them more susceptible to buckling failure. This paper shows that once the beam is positioned
Burgoyne, Chris
Radio Frequency Station - Beam Dynamics Interaction in Circular Accelerators
The longitudinal beam dynamics in circular accelerators is mainly defined by the interaction of the beam current with the accelerating Radio Frequency (RF) stations. For stable operation, Low Level RF (LLRF) feedback systems are employed to reduce coherent instabilities and regulate the accelerating voltage. The LLRF system design has implications for the dynamics and stability of the closed-loop RF systems as well as for the particle beam, and is very sensitive to the operating range of accelerator currents and energies. Stability of the RF loop and the beam are necessary conditions for reliable machine operation. This dissertation describes theoretical formalisms and models that determine the longitudinal beam dynamics based on the LLRF implementation, time domain simulations that capture the dynamic behavior of the RF station-beam interaction, and measurements from the Positron-Electron Project (PEP-II) and the Large Hadron Collider (LHC) that validate the models and simulations. These models and simulations are structured to capture the technical characteristics of the system (noise contributions, non-linear elements, and more). As such, they provide useful results and insight for the development and design of future LLRF feedback systems. They also provide the opportunity to study diverse longitudinal beam dynamics effects such as coupled-bunch impedance driven instabilities and single bunch longitudinal emittance growth. Coupled-bunch instabilities and RF station power were the performance limiting effects for PEP-II. The sensitivity of the instabilities to individual LLRF parameters, the effectiveness of alternative operational algorithms, and the possible tradeoffs between RF loop and beam stability were studied. New algorithms were implemented, with significant performance improvement leading to a world record current during the last PEP-II run of 3212 mA for the Low Energy Ring. Longitudinal beam emittance growth due to RF noise is a major concern for LHC. Simulations studies and measurements were conducted that clearly show the correlation between RF noise and longitudinal bunch emittance, identify the major LLRF noise contributions, and determine the RF component dominating this effect. With these results, LHC upgrades and alternative algorithms are evaluated to reduce longitudinal emittance growth during operations. The applications of this work are described with regard to future machines and analysis of new technical implementations, as well as to possible future work which would continue the directions of this dissertation.
Mastoridis, Themistoklis; /Stanford U., Elect. Eng. Dept. /SLAC
Superficial dosimetry imaging based on ?erenkov emission for external beam radiotherapy with megavoltage x-ray beam
Purpose: ?erenkov radiation emission occurs in all tissue, when charged particles (either primary or secondary) travel at velocity above the threshold for the ?erenkov effect (about 220 KeV in tissue for electrons). This study presents the first examination of optical ?erenkov emission as a surrogate for the absorbed superficial dose for MV x-ray beams.Methods: In this study, Monte Carlo simulations of flat and curved surfaces were studied to analyze the energy spectra of charged particles produced in different regions near the surfaces when irradiated by MV x-ray beams. ?erenkov emission intensity and radiation dose were directly simulated in voxelized flat and cylindrical phantoms. The sampling region of superficial dosimetry based on ?erenkov radiation was simulated in layered skin models. Angular distributions of optical emission from the surfaces were investigated. Tissue mimicking phantoms with flat and curved surfaces were imaged with a time domain gating system. The beam field sizes (50 � 50�200 � 200 mm{sup 2}), incident angles (0��70�) and imaging regions were all varied.Results: The entrance or exit region of the tissue has nearly homogeneous energy spectra across the beam, such that their ?erenkov emission is proportional to dose. Directly simulated local intensity of ?erenkov and radiation dose in voxelized flat and cylindrical phantoms further validate that this signal is proportional to radiation dose with absolute average discrepancy within 2%, and the largest within 5% typically at the beam edges. The effective sampling depth could be tuned from near 0 up to 6 mm by spectral filtering. The angular profiles near the theoretical Lambertian emission distribution for a perfect diffusive medium, suggesting that angular correction of ?erenkov images may not be required even for curved surface. The acquisition speed and signal to noise ratio of the time domain gating system were investigated for different acquisition procedures, and the results show there is good potential for real-time superficial dose monitoring. Dose imaging under normal ambient room lighting was validated, using gated detection and a breast phantom.Conclusions: This study indicates that ?erenkov emission imaging might provide a valuable way to superficial dosimetry imaging in real time for external beam radiotherapy with megavoltage x-ray beams.
Zhang, Rongxiao [Department of Physics and Astronomy, Dartmouth College, Hanover, New Hampshire 03755 and Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755 (United States)] [Department of Physics and Astronomy, Dartmouth College, Hanover, New Hampshire 03755 and Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755 (United States); Glaser, Adam K. [Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755 (United States)] [Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755 (United States); Gladstone, David J.; Fox, Colleen J. [Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire 03766 and Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire 03755 (United States)] [Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire 03766 and Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire 03755 (United States); Pogue, Brian W. [Department of Physics and Astronomy, Dartmouth College, Hanover, New Hampshire 03755 (United States) [Department of Physics and Astronomy, Dartmouth College, Hanover, New Hampshire 03755 (United States); Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire 03766 (United States); Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755 (United States)
Electron beam diagnostic for space charge measurement of an ion beam
A non-perturbing electron beam diagnostic system for measuring the charge distribution of an ion beam is developed for Heavy Ion Fusion (HIF) beam physics studies. Conventional diagnostics require temporary insertion of sensors into the beam, but such diagnostics stop the beam, or significantly alter its properties. In this diagnostic a low energy, low current electron beam is swept transversely across the ion beam; the measured electron beam deflection is used to infer the charge density profile of the ion beam. The initial application of this diagnostic is to the Neutralized Transport Experiment (NTX), which is exploring the physics of space-charge-dominated beam focusing onto a small spot using a neutralizing plasma. Design and development of this diagnostic and performance with the NTX ion beamline is presented.
Roy, Prabir K.; Yu, Simon S.; Henestroza, Enrique; Eylon, Shmuel; Shuman, Derek B.; Ludvig, Jozsef; Bieniosek, Frank M.; Waldron, William L.; Greenway, Wayne G.; Vanecek, David L.; Hannink, Ryan; Amezcua, Monserrat
The Center for Beam Physics is a multi-disciplinary research and development unit in the Accelerator and Fusion Research Division at Lawrence Berkeley Laboratory. At the heart of the Center`s mission is the fundamental quest for mechanisms of acceleration, radiation and focusing of energy. Dedicated to exploring the frontiers of the physics of (and with) particle and photon beams, its primary mission is to promote the science and technology of the production, manipulation, storage and control systems of charged particles and photons. The Center serves this mission via conceptual studies, theoretical and experimental research, design and development, institutional project involvement, external collaborations, association with industry and technology transfer. This roster provides a glimpse at the scientists, engineers, technical support, students, and administrative staff that make up this team and a flavor of their multifaceted activities during 1993.
Not Available
Oxygen ion-beam microlithography
A method of providing and developing a resist on a substrate for constructing integrated circuit (IC) chips includes the following steps: of depositing a thin film of amorphous silicon or hydrogenated amorphous silicon on the substrate and exposing portions of the amorphous silicon to low-energy oxygen ion beams to oxidize the amorphous silicon at those selected portions. The nonoxidized portions are then removed by etching with RF-excited hydrogen plasma. Components of the IC chip can then be constructed through the removed portions of the resist. The entire process can be performed in an in-line vacuum production system having several vacuum chambers. Nitrogen or carbon ion beams can also be used. 5 figures.
Tsuo, Y.S.
Oxygen ion-beam microlithography
A method of providing and developing a resist on a substrate for constructing integrated circuit (IC) chips includes the following steps: of depositing a thin film of amorphous silicon or hydrogenated amorphous silicon on the substrate and exposing portions of the amorphous silicon to low-energy oxygen ion beams to oxidize the amorphous silicon at those selected portions. The nonoxidized portions are then removed by etching with RF-excited hydrogen plasma. Components of the IC chip can then be constructed through the removed portions of the resist. The entire process can be performed in an in-line vacuum production system having several vacuum chambers. Nitrogen or carbon ion beams can also be used.
Tsuo, Y. Simon (Lakewood, CO)
Neutron beam testing of triblades
Four IBM Triblades were tested in the Irradiation of Chips and Electronics facility at the Los Alamos Neutron Science Center. Triblades include two dual-core Opteron processors and four PowerXCell 8i (Cell) processors. The Triblades were tested in their field configuration while running different applications, with the beam aimed at the Cell processor or the Opteron running the application. Testing focused on the Cell processors, which were tested while running five different applications and an idle condition. While neither application nor Triblade was statistically important in predicting the hazard rate, the hazard rate when the beam was aimed at the Opterons was significantly higher than when it was aimed at the Cell processors. In addition, four Cell blades (one in each Triblade) suffered voltage shorts, leading to their inoperability. The hardware tested is the same as that in the Roadrunner supercomputer.
Michalak, Sarah E [Los Alamos National Laboratory; Du Bois, Andrew J [Los Alamos National Laboratory; Storlie, Curtis B [Los Alamos National Laboratory; Rust, William N [Los Alamos National Laboratory; Du Bois, David H [Los Alamos National Laboratory; Modl, David G [Los Alamos National Laboratory; Quinn, Heather M [Los Alamos National Laboratory; Blanchard, Sean P [Los Alamos National Laboratory; Manuzzato, Andrea [UNIV DEGLI STUDI DI PADOVA ITALY
VAV Reheat Versus Active Chilled Beams and DOAS
Andrey. Don�t Turn Active Beams Into Expensive Diffusers,added costs of the piping and beams for ACBs are simply too1. Simmonds, Peter. To Beam or not To Beam? , Engineered
Stein, Jeff; Taylor, Steven
Toroidal Plasma Rotation in the Princeton Large Torus Induced by Neutral-Beam Injection
Science Journals Connector (OSTI)
Toroidal plasma rotation, generated by toroidally unbalanced neutral-beam injection into the Princeton Large Torus, has been measured by Doppler shifts of several atomic spectral lines. These measurements produce the time evolution and spatial distribution of the rotation from which a momentum confinement time, comparable to the ion energy confinement time, is deduced.
S. Suckewer; H. P. Eubank; R. J. Goldston; E. Hinnov; N. R. Sauthoff
An X-ray beam finder for locating a focal spot of an X-ray tube includes a mass of X-ray opaque material having first and second axially-aligned, parallel-opposed faces connected by a plurality of substantially identical parallel holes perpendicular to the faces and a film holder for holding X-ray sensitive film tightly against one face while the other face is placed in contact with the window of an X-ray head.
Gilbert, H.W.
W-Band Sheet Beam Klystron Design
Sheet beam devices provide important advantages for very high power, narrow bandwidth RF sources like accelerator klystrons [1]. Reduced current density and increased surface area result in increased power capabi1ity, reduced magnetic fields for focusing and reduced cathode loading. These advantages are offset by increased complexity, beam formation and transport issues and potential for mode competition in the ovennoded cavities and drift tube. This paper will describe the design issues encountered in developing a 100 kW peak and 2 kW average power sheet beam k1ystron at W-band including beam formation, beam transport, circuit design, circuit fabrication and mode competition.
Scheitrum, G.; Caryotakis, G.; Burke, A.; Jensen, A.; Jongewaard, E.a Krasnykh, A.; Neubauer, M.; Phillips, R.; Rauenbuehler, K.; /SLAC
Scattering apodizer for laser beams
A method is disclosed for apodizing a laser beam to smooth out the production of diffraction peaks due to optical discontinuities in the path of the laser beam, such method comprising introduction of a pattern of scattering elements for reducing the peak intensity in the region of such optical discontinuities, such pattern having smoothly tapering boundaries in which the distribution density of the scattering elements is tapered gradually to produce small gradients in the distribution density, such pattern of scattering elements being effective to reduce and smooth out the diffraction effects which would otherwise be produced. The apodizer pattern may be produced by selectively blasting a surface of a transparent member with fine abrasive particles to produce a multitude of minute pits. In one embodiment, a scattering apodizer pattern is employed to overcome diffraction patterns in a multiple element crystal array for harmonic conversion of a laser beam. The interstices and the supporting grid between the crystal elements are obscured by the gradually tapered apodizer pattern of scattering elements.
Summers, Mark A. (Livermore, CA); Hagen, Wilhelm F. (Livermore, CA); Boyd, Robert D. (Livermore, CA)
Scattering apodizer for laser beams
A method is disclosed for apodizing a laser beam to smooth out the production of diffraction peaks due to optical discontinuities in the path of the laser beam, such method comprising introduction of a pattern of scattering elements for reducing the peak intensity in the region of such optical discontinuities, such pattern having smoothly tapering boundaries in which the distribution density of the scattering elements is tapered gradually to produce small gradients in the distribution density, such pattern of scattering elements being effective to reduce and smooth out the diffraction effects which would otherwise be produced. The apodizer pattern may be produced by selectively blasting a surface of a transparent member with fine abrasive particles to produce a multitude of minute pits. In one embodiment, a scattering apodizer pattern is employed to overcome diffraction patterns in a multiple element crystal array for harmonic conversion of a laser beam. The interstices and the supporting grid between the crystal elements are obscured by the gradually tapered apodizer pattern of scattering elements.
Summers, M.A.; Hagen, W.F.; Boyd, R.D.
Characteristics of flattening filter free beams at low monitor unit settings
Purpose: Newer linear accelerators (linacs) have been equipped to deliver flattening filter free (FFF) beams. When FFF beams are used for step-and-shoot intensity-modulated radiotherapy (IMRT), the stability of delivery of small numbers of monitor units (MU) is important. The authors developed automatic measurement techniques to evaluate the stability of the dose profile, dose linearity, and consistency. Here, the authors report the performance of the Artiste� accelerator (Siemens, Erlangen, Germany) in delivering low-MU FFF beams.Methods: A 6 MV flattened beam (6X) with 300 MU/min dose rate and FFF beams of 7 (7XU) and 11 MV (11XU), each with a 500 MU/min dose rate, were measured at 1, 2, 3, 5, 8, 10, and 20 MU settings. For the 2000 MU/min dose rate, the 7 (7XUH) and 11 MV (11XUH) beams were set at 10, 15, 20, 25, and 30 MU because of the limits of the minimum MU settings. Beams with 20 � 20 and 10 � 10 cm{sup 2} field sizes were alternately measured ten times in intensity modulated (IM) mode, with which Siemens linacs regulate beam delivery for step-and-shoot IMRT. The in- and crossplane beam profiles were measured using a Profiler� Model 1170 (Sun Nuclear Corporation, Melbourne, FL) in multiframe mode. The frames of 20 � 20 cm{sup 2} beams were identified at the off-axis profile. The 6X beam profile was normalized at the central axis. The 7 and 11 MV FFF beam profiles were rescaled to set the dose at the central axis at 145% and 170%, respectively. Point doses were also measured using a Farmer-type ionization chamber and water-equivalent solid phantom to evaluate the linearity and consistency of low-MU beam delivery. The values displayed on the electrometer were recognized with a USB-type camera and read with open-source optical character recognition software.Results: The symmetry measurements of the 6X, 7XU, and 11XU beam profiles were better than 2% for beams ?2 MU and improved with increasing MU. The variations in flatness of FFF beams ?2 MU were �5%. The standard deviation of the symmetry and flatness also decreased with increasing MU. The linearity of the 6X beam was �1% and �2% for the beams of ?5 and ?3 MU, respectively. The 7XU and 11XU beams of ?2 MU showed linearity with �2% except the 7XU beam of 8 MU (+2.9%). The profiles of the FFF beams with 2000 and 500 MU/min dose rate were similar.Conclusions: The characteristics of low-MU beams delivered in IM mode were evaluated using an automatic measurement system developed in this study. The authors demonstrated that the profiles of FFF beams of the Artiste� linac were highly stable, even at low MU. The linearity of dose output was also stable for beams ?2 MU.
Akino, Yuichi [Department of Radiology, Osaka University Hospital, Suita, Osaka 565-0871, Japan and Department of Radiation Oncology, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871 (Japan)] [Department of Radiology, Osaka University Hospital, Suita, Osaka 565-0871, Japan and Department of Radiation Oncology, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871 (Japan); Ota, Seiichi; Inoue, Shinichi; Mizuno, Hirokazu [Department of Radiology, Osaka University Hospital, Suita, Osaka 565-0871 (Japan)] [Department of Radiology, Osaka University Hospital, Suita, Osaka 565-0871 (Japan); Sumida, Iori; Yoshioka, Yasuo; Ogawa, Kazuhiko [Department of Radiation Oncology, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871 (Japan)] [Department of Radiation Oncology, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871 (Japan); Isohashi, Fumiaki [Oncology Center, Osaka University Hospital, Suita, Osaka 565-0871 (Japan)] [Oncology Center, Osaka University Hospital, Suita, Osaka 565-0871 (Japan)
Typical beam lines are comprised of an assembly of vacuum valves and shutters referred to as a ''front end'', optical elements to monochromatize, focus and split the photon beam, and an experimental area where a target sample is placed into the photon beam and data from the interaction is detected and recorded. Windows are used to separate sections of beam lines that are not compatible with storage ring ultra high vacuum. Some experimental beam lines share a common vacuum with storage rings. Sections of beam lines are only allowed to vent up to atmospheric pressure using pure nitrogen gas after a vacuum barrier is established to protect ring vacuum. The front end may only be bled up when there is no current in the machine. This is especially true on the VUV storage ring where for most experiments, windows are not used. For the shorter wavelength, more energetic photons of the x-ray ring, beryllium windows are used at various beam line locations so that the monochromator, mirror box or sample chamber may be used in a helium atmosphere or rough vacuum. The window separates ring vacuum from the environment of the downstream beam line components. The stored beam lifetime in the storage rings and the maintenance of desirable reflection properties of optical surfaces depend upon hydrocarbon-free, ultra-high vacuum systems. Storage ring vacuum systems will operate at pressures of {approximately} 1 x 10{sup {minus}10} Torr without beam and {approximately} 1 x 10{sup {minus}9} Torr with beam. Systems are free of hydrocarbons in the sense that no pumps, valves, etc. containing organics are used. Components are all-metal, chemically cleaned and bakeable. To the extent that beam lines share a common vacuum with the storage ring, the same criteria will hold for beam line components. The design philosophy for NSLS beam lines is to use all-metal, hydrocarbon-free front end components and recommend that experimenters use this approach for common vacuum hardware downstream of front ends. O-ring-sealed valves, if used, are not permitted upstream of the monochromator exit aperture. It will be the responsibility of users to demonstrate that their experiment will not degrade the pressure or quality of the storage ring vacuum. As a matter of operating policy, all beam lines will be monitored for prescribed pressure and the contribution of high mass gases to this pressure each time a beam line has been opened to ring vacuum.
Particle beam injector system and method
Methods and devices enable coupling of a charged particle beam to a radio frequency quadrupole accelerator. Coupling of the charged particle beam is accomplished, at least in-part, by relying on of sensitivity of the input phase space acceptance of the radio frequency quadrupole to the angle of the input charged particle beam. A first electric field across a beam deflector deflects the particle beam at an angle that is beyond the acceptance angle of the radio frequency quadrupole. By momentarily reversing or reducing the established electric field, a narrow portion of the charged particle beam is deflected at an angle within the acceptance angle of the radio frequency quadrupole. In another configuration, beam is directed at an angle within the acceptance angle of the radio frequency quadrupole by the first electric field and is deflected beyond the acceptance angle of the radio frequency quadrupole due to the second electric field.
Guethlein, Gary
Paraxial Light Beams with Angular Momentum
Fundamental and applied concepts concerning the ability of light beams to carry a certain mechanical angular momentum with respect to the propagation axis are reviewed and discussed. Following issues are included: Historical reference; Angular momentum of a paraxial beam and its constituents; Spin angular momentum and paradoxes associated with it; Orbital angular momentum; Circularly-spiral beams: examples and methods of generation; Orbital angular momentum and the intensity moments; Symmetry breakdown and decomposition of the orbital angular momentum; Mechanical models of the vortex light beams; Mechanical action of the beam angular momentum; Rotational Doppler effect, its manifestation in the image rotation; Spectrum of helical harmonics and associated problems; Non-collinear rotational Doppler effect; Properties of a beam forcedly rotating around its own axis. Research prospects and ways of practical utilization of optical beams with angular momentum.
A. Bekshaev; M. Soskin; M. Vasnetsov
S&TR | March/April 2008: Standardizing the Art of Electron-Beam Welding
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Standardizing the Art of Electron-Beam Welding. Standardizing the Art of Electron-Beam Welding. WELDED materials are an integral part of everyday life. Appliances, cars, and bridges are all made by welding materials together. But not all welds are created equal. Welding methods vary in complexity, time, and cost, depending on a product's requirements and purpose. In electron-beam (EBeam) welding, an electron beam generated in a vacuum creates a fusing heat source that can unite almost any metals. This method produces deep welds without adding excessive heat that can adversely affect the properties of the surrounding metal. In the nuclear energy and aerospace industries, electron-beam welding is preferred for manufacturing high-value welds-those in which defects cannot be tolerated. The Department of Energy's (DOE's) nuclear weapons
Transverse coherence saturation: A method to enhance the coherence of x-ray beams
Science Journals Connector (OSTI)
A method is proposed to generate improved coherence in x-ray beams. The method leaves the photon source unchanged, and improves transverse coherence by reordering the emitted radiation through dynamical optical means (i.e., with at least one moving optical component). Since the method increases the transverse coherence of beams, it thus reduces the time needed to perform certain types of observations, such as in microscopy, and interference experiments such as holography. It does not increase the longitudinal coherence of beams. However, it can be supplemented by other means to increase longitudinal coherence. It does not increase the brightness, but allows one to more efficiently utilize beams of a given brightness. The use of this method with photons generated by pulsed electron beams, including those in storage rings, seems particularly appropriate.
Paul L. Csonka
Searching for a U-boson with a positron beam
A high sensitivity search for a light \\Ub{} by means of a positron beam incident on a hydrogen target is proposed. We described a concept of the experiment and two possible realizations. The projected result of this experiment corresponds to an upper limit on the square of coupling constant $ |f_{_{eU}}|^2 = 3 \\times 10^{-9}$ with a signal to noise ratio of five.
B. Wojtsekhowski
Beam-Beam Simulations for a Single Pass SuperB-Factory
A study of beam-beam collisions for an asymmetric single pass SuperB-Factory is presented [1]. In this scheme an e{sup -} and an e{sup +} beam are first stored and damped in two Damping Rings (DR), then extracted, compressed and focused to the IP. After collision the two beams are re-injected in the DR to be damped and extracted for collision again. The explored beam parameters are similar to those used in the design of the International Linear Collider, except for the beam energies. Flat beams and round beams were compared in the simulations in order to optimize both luminosity performances and beam blowup after collision. With such approach a luminosity of the order of 10{sup 36} cm{sup -2} s{sup -1} can be achieved.
Biagini, M.E.; /Frascati; Raimondi, P.; Seeman, J.; /SLAC; Schulte, D.; /CERN
Projection imaging of photon beams by the Cerenkov effect
Purpose: A novel technique for beam profiling of megavoltage photon beams was investigated for the first time by capturing images of the induced Cerenkov emission in water, as a potential surrogate for the imparted dose in irradiated media. Methods: A high-sensitivity, intensified CCD camera (ICCD) was configured to acquire 2D projection images of Cerenkov emission from a 4 Multiplication-Sign 4 cm{sup 2} 6 MV linear accelerator (LINAC) x-ray photon beam operating at a dose rate of 400 MU/min incident on a water tank with transparent walls. The ICCD acquisition was gated to the LINAC sync pulse to reduce background light artifacts, and the measurement quality was investigated by evaluating the signal to noise ratio and measurement repeatability as a function of delivered dose. Monte Carlo simulations were used to derive a calibration factor for differences between the optical images and deposited dose arising from the anisotropic angular dependence of Cerenkov emission. Finally, Cerenkov-based beam profiles were compared to a percent depth dose (PDD) and lateral dose profile at a depth of d{sub max} from a reference dose distribution generated from the clinical Varian ECLIPSE treatment planning system (TPS). Results: The signal to noise ratio was found to be 20 at a delivered dose of 66.6 cGy, and proportional to the square root of the delivered dose as expected from Poisson photon counting statistics. A 2.1% mean standard deviation and 5.6% maximum variation in successive measurements were observed, and the Monte Carlo derived calibration factor resulted in Cerenkov emission images which were directly correlated to deposited dose, with some spatial issues. The dose difference between the TPS and PDD predicted by Cerenkov measurements was within 20% in the buildup region with a distance to agreement (DTA) of 1.5-2 mm and {+-}3% at depths beyond d{sub max}. In the lateral profile, the dose difference at the beam penumbra was within {+-}13% with a DTA of 0-2 mm, {+-}5% in the central beam region, and 2%-3% in the beam umbra. Conclusions: The results from this initial study demonstrate the first documented use of Cerenkov emission imaging to profile x-ray photon LINAC beams in water. The proposed modality has several potential advantages over alternative methods, and upon future refinement may prove to be a robust and novel dosimetry method.
Glaser, Adam K.; Davis, Scott C.; McClatchy, David M.; Zhang, Rongxiao; Pogue, Brian W.; Gladstone, David J. [Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755 (United States); Department of Physics and Astronomy, Dartmouth College, Hanover, New Hampshire 03755 (United States); Thayer School of Engineering and Department of Physics and Astronomy, Dartmouth College, Hanover, New Hampshire 03755 (United States); Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire 03766 (United States)
Optics of electron beam in the Recycler
Electron cooling of 8.9 GeV/c antiprotons in the Recycler ring (Fermilab) requires high current and good quality of the DC electron beam. Electron trajectories of {approx}0.2 A or higher DC electron beam have to be parallel in the cooling section, within {approx}0.2 mrad, making the beam envelope cylindrical. These requirements yielded a specific scheme of the electron transport from a gun to the cooling section, with electrostatic acceleration and deceleration in the Pelletron. Recuperation of the DC beam limits beam losses at as tiny level as {approx}0.001%, setting strict requirements on the return electron line to the Pelletron and a collector. To smooth the beam envelope in the cooling section, it has to be linear and known at the transport start. Also, strength of the relevant optic elements has to be measured with good accuracy. Beam-based optic measurements are being carried out and analyzed to get this information. They include beam simulations in the Pelletron, differential optic (beam response) measurements and simulation, beam profile measurements with optical transition radiation, envelope measurements and analysis with orifice scrapers. Current results for the first half-year of commissioning are presented. Although electron cooling is already routinely used for pbar stacking, its efficiency is expected to be improved.
Burov, Alexey V.; Kazakevich, G.; Kroc, T.; Lebedev, V.; Nagaitsev, S.; Prost, L.; Pruss, S.; Shemyakin, A.; Sutherland, M.; Tiunov, M.; Warner, A.; /Fermilab
Low Emittance Electron Beam Studies
We have studied the properties of a low emittance electron beam produced by laser pulses incident onto an rf gun photocathode. The experiments were carried out at the A0 photoinjector at Fermilab. Such beam studies are necessary for fixing the design of new Linear Colliders as well as for the development of Free Electron Lasers. An overview of the A0 photoinjector is given in Chapter 1. In Chapter 2 we describe the A0 photoinjector laser system. A stable laser system is imperative for reliable photoinjector operation. After the recent upgrade, we have been able to reach a new level of stability in the pulse-to-pulse fluctuations of the pulse amplitude, and of the temporal and transverse profiles. In Chapter 3 we present a study of transverse emittance versus the shape of the photo-cathode drive-laser pulse. For that purpose a special temporal profile laser shaping device called a pulse-stacker was developed. In Chapter 4 we discuss longitudinal beam dynamics studies using a two macro-particle bunch; this technique is helpful in analyzing pulse compression in the magnetic chicane, as well as velocity bunching effects in the rf-gun and the 9-cell accelerating cavity. In Chapter 5 we introduce a proposal for laser acceleration of electrons. We have developed a laser functioning on the TEM*{sub 01} mode, a mode with a longitudinal electric field component which is suitable for such a process. Using this technique at energies above 40 MeV, one would be able to observe laser-based acceleration.
Tikhoplav, Rodion; /Rochester U.; ,
Ultrafast electron beam imaging of femtosecond laser-induced plasma
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Ultrafast electron beam imaging of femtosecond laser-induced plasma Ultrafast electron beam imaging of femtosecond laser-induced plasma dynamics Title Ultrafast electron beam imaging of femtosecond laser-induced plasma dynamics Publication Type Journal Article Year of Publication 2010 Authors Li, Junjie, Xuan Wang, Zhaoyang Chen, Richard Clinite, Samuel S. Mao, Pengfei Zhu, Zhengming Sheng, Jie Zhang, and Jianming Cao Journal Journal of Applied Physics Volume 107 Issue 8 Date Published 03/2010 Keywords copper, electron beam applications, high-speed optical techniques, laser ablation, plasma diagnostics, plasma production by laser Abstract Plasma dynamics in the early stage of laser ablation of a copper target are investigated in real time by making ultrafast electron shadow images and electron deflectometry measurements. These complementary techniques provide both a global view and a local perspective of the associated transient electric field and charge expansion dynamics. The results reveal that the charge cloud above the target surface is composed predominantly of thermally ejected electrons and that it is self-expanding, with a fast front-layer speed exceeding 107 m/s. The average electric field strength of the charge cloud induced by a pump fluence of 2.2 J/cm2 is estimated to be ∼ 2.4×105 V/m.
Linac4 45 keV Proton Beam Measurements
Linac4 is a 160 MeV normal-conducting H- linear accelerator, which will replace the 50 MeV proton Linac2 as injector for the CERN proton complex. Commissioning of the low energy part - comprising the H - source, a 45 keV Low Energy Beam Transport line (LEBT), a 3 MeV Radiofrequency Quadrupole (RFQ) and a Medium Energy Beam Transport (MEBT) - will start in fall 2012 on a dedicated test stand installation. In preparation to this, preliminary measurements were taken using a 45 keV proton source and a temporary LEBT setup, with the aim of characterising the output beam by comparison with the predictions of simulations. At the same time this allowed a first verification of the functionalities of diagnostics instrumentation and acquisition software tools. Measurements of beam profile, emittance and intensity were taken in three different setups: right after the source, after the first and after the second LEBT solenoids respectively. Particle distributions were reconstructed from emittance scan...
Bellodi, G; Hein, L M; Lallement, J-B; Lombardi, A M; Midttun, O; Scrivens, R; Posocco, P A
Dose, exposure time and resolution in serial X-ray crystallography
Science Journals Connector (OSTI)
Using detailed simulation and analytical models, the exposure time is estimated for serial crystallography, where hydrated laser-aligned proteins are sprayed across a continuous synchrotron beam.
Starodub, D.
Protective laser beam viewing device
A protective laser beam viewing system or device including a camera selectively sensitive to laser light wavelengths and a viewing screen receiving images from the laser sensitive camera. According to a preferred embodiment of the invention, the camera is worn on the head of the user or incorporated into a goggle-type viewing display so that it is always aimed at the area of viewing interest to the user and the viewing screen is incorporated into a video display worn as goggles over the eyes of the user.
Neil, George R.; Jordan, Kevin Carl
Ramsey Experiments Using Neutron Beams
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Abstract Ramsey's technique of separated oscillatory fields adapted to cold neutron beams is a very sensitive method to probe for spin- dependent interactions of neutrons with magnetic and pseudomagnetic fields. In the last couple of years several distinctive experiments using this technique have been performed, e.g. to determine the incoherent neutron scattering length of the deuteron, to perform polarized neutron imaging of magnetic fields and samples, and lately, to search for new light spin-1 bosons. Here, some of these results are reviewed and possible future measurements with respect to a pulsed neutron source are presented.
Florian M. Piegsa
Proton beam therapy control system
A tiered communications architecture for managing network traffic in a distributed system. Communication between client or control computers and a plurality of hardware devices is administered by agent and monitor devices whose activities are coordinated to reduce the number of open channels or sockets. The communications architecture also improves the transparency and scalability of the distributed system by reducing network mapping dependence. The architecture is desirably implemented in a proton beam therapy system to provide flexible security policies which improve patent safety and facilitate system maintenance and development.
Baumann, Michael A. (Riverside, CA); Beloussov, Alexandre V. (Bernardino, CA); Bakir, Julide (Alta Loma, CA); Armon, Deganit (Redlands, CA); Olsen, Howard B. (Colton, CA); Salem, Dana (Riverside, CA)
Proton beam therapy control system
A tiered communications architecture for managing network traffic in a distributed system. Communication between client or control computers and a plurality of hardware devices is administered by agent and monitor devices whose activities are coordinated to reduce the number of open channels or sockets. The communications architecture also improves the transparency and scalability of the distributed system by reducing network mapping dependence. The architecture is desirably implemented in a proton beam therapy system to provide flexible security policies which improve patent safety and facilitate system maintenance and development.
Baumann, Michael A. (Riverside, CA); Beloussov, Alexandre V. (San Bernardino, CA); Bakir, Julide (Alta Loma, CA); Armon, Deganit (Longmeadow, MA); Olsen, Howard B. (Irvine, CA); Salem, Dana (Riverside, CA)
Proton beam therapy control system
A tiered communications architecture for managing network traffic in a distributed system. Communication between client or control computers and a plurality of hardware devices is administered by agent and monitor devices whose activities are coordinated to reduce the number of open channels or sockets. The communications architecture also improves the transparency and scalability of the distributed system by reducing network mapping dependence. The architecture is desirably implemented in a proton beam therapy system to provide flexible security policies which improve patent safety and facilitate system maintenance and development.
Baumann, Michael A; Beloussov, Alexandre V; Bakir, Julide; Armon, Deganit; Olsen, Howard B; Salem, Dana
A cryogenic current comparator for the absolute measurement of nA beams
A new type of beam transformer, based on the principle of a Cryogenic Current Comparator (CCC), was built to measure extracted ion beams from the SIS, the heavy ion synchroton at GSI. A current resolution of 0.006-0.065 nA/{radical}(Hz), depending on the frequency range, could be achieved allowing us to measure ion beams with intensities greater than 10{sup 9} particles per second with high accuracy. Numerous investigations were carried out to study the zero drift of the system which shows a strong exponential slope with two time constants. In addition, the influence of external magnetic fields was measured. Furthermore the microphonic sensitivity of the system was studied by measuring noise spectra of the detector's vibration and the output signal. Measurements with neon and argon beams will be presented and compared with signals emitted from Secondary Emission Monitors (SEM). Another measuring function of the CCC-detector aims at the analysis of the beam's time structure to get information about beam spill fluctuations. With an extended bandwidth (0-20 kHz) of the detector system it is now possible to compare simulations of extracted beams from synchrotons with measurements of the CCC.
Peters, Andreas; Reeg, Hannes; Schroeder, Claus Hermann [Gesellschaft fuer Schwerionenforschung, Darmstadt (Germany); Vodel, Wolfgang; Koch, Helmar; Neubert, Ralf [Institut fuer Festkoeperphysik, Friedrich Schiller Universitaet, Jena (Germany)
Nano-electron beam induced current and hole charge dynamics through uncapped Ge nanocrystals
Dynamics of hole storage in spherical Ge nanocrystals (NCs) formed by a two step dewetting/nucleation process on an oxide layer grown on an n-doped <001> silicon substrate is studied using a nano-electron beam induced current technique. Carrier generation is produced by an electron beam irradiation. The generated current is collected by an atomic force microscope--tip in contact mode at a fixed position away from the beam spot of about 0.5 {mu}m. This distance represents the effective diffusion length of holes. The time constants of holes charging are determined and the effect of the NC size is underlined.
Marchand, A.; El Hdiy, A.; Troyon, M. [Laboratoire de Recherche en Nanosciences, Bat. 6, case no 15, UFR Sciences, Universite de Reims Champagne Ardenne, 51687 Reims Cedex 2 (France); Amiard, G.; Ronda, A.; Berbezier, I. [IM2NP, Faculte des Sciences et Techniques, Campus de Saint Jerome - Case 142, Avenue Escadrille Normandie Niemen, 13397 Marseille Cedex 20 (France)
Quantum Key Ditribution Based on Quantum Intensity Correlation of Twin Beams
A new and simple quantum key distribution scheme based on the quantum intensity correlation of optical twin beams and the directly local measurements of intensity noise of single optical beam is presented and experimentally demonstrated. Using the twin beams with the quantum intensity correlation of 5dB the effective bit rate of $2\\times 10^7bits/s$ is completed. The noncloning of quantum systems and the sensitivity of the existing correlations to losses provide the physical mechamism for the security against eavesdropping. In the presented scheme the signal modulation and homodyne detection are not needed.
Xiaojun Jia; Xiaolong Su; Qing Pan; Kunchi Peng; Changde Xie
Beam losses due to abrupt crab cavity failures in the LHC
A major concern for the implementation of crab crossing in a future High-Luminosity LHC (HL-LHC) is machine protection in an event of a fast crab-cavity failure. Certain types of abrupt crab-cavity amplitude and phase changes are simulated to characterize the effect of failures on the beam and the resulting particle-loss signatures. The time-dependent beam loss distributions around the ring and particle trajectories obtained from the simulations allow for a first assessment of the resulting beam impact on LHC collimators and on sensitive components around the ring. Results for the nominal LHC lattice is presented.
Baer, T.; Barranco, J.; Calaga, R.; Tomas, R.; Wenninger, B.; Yee, B.; Zimmermann, F.
Integrating and automating the software environment for the Beam and Radiation Monitoring for CMS
The real-time online visualization framework used by the Beam and Radiation Monitoring group at the Compact Muon Solenoid at Large Hadron Collider, CERN. The purpose of the visualization framework is to provide real-time diagnostic of beam conditions, which defines the set of the requirements to be met by the framework. Those requirements include data quality assurance, vital safety issues, low latency, data caching, etc. The real-time visualization framework is written in the Java programming language and based on JDataViewer--a plotting package developed at CERN. At the current time the framework is run by the Beam and Radiation Monitoring, Pixel, Tracker groups, Run Field Manager and others. It contributed to real-time data analysis during 2009-2010 runs as a stable monitoring tool. The displays reflect the beam conditions in a real-time with the low latency level, thus it is the first place at the CMS detector where the beam collisions are observed.
Filyushkina, Olga; Juslin, J
Yuan T. Lee's Crossed Molecular Beam Experiment
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Yuan T. Lee's Crossed Molecular Beam Experiment Yuan T. Lee's Crossed Molecular Beam Experiment Home | Staff | Search | Advisory Committee | User Facilities | Laboratories | Congress | Budget Yuan T. Lee's Crossed Molecular Beam Experiment http://web.archive.org/web/20000902074635/www.er.doe.gov/production/bes/YuanLee_Exp.html (1 of 4)4/7/2006 2:46:13 PM Yuan T. Lee's Crossed Molecular Beam Experiment The above illustration was drawn by Professor Yuan T. Lee, who shared the 1986 Nobel Prize in Chemistry. It shows the design for his crossed molecular beam experiment described in the story beginning on page 27 of "Basic Energy Sciences: Summary of Accomplishments" (DOE/ER-0455P, May 1990); the story is also copied below. The purpose of this experiment was to study the chemical reaction of sodium atoms with oxygen molecules. In the experiment, a beam of sodium atoms (green,
Radiation beam calorimetric power measurement system
A radiation beam calorimetric power measurement system for measuring the average power of a beam such as a laser beam, including a calorimeter configured to operate over a wide range of coolant flow rates and being cooled by continuously flowing coolant for absorbing light from a laser beam to convert the laser beam energy into heat. The system further includes a flow meter for measuring the coolant flow in the calorimeter and a pair of thermistors for measuring the temperature difference between the coolant inputs and outputs to the calorimeter. The system also includes a microprocessor for processing the measured coolant flow rate and the measured temperature difference to determine the average power of the laser beam.
Baker, John (Livermore, CA); Collins, Leland F. (Pleasanton, CA); Kuklo, Thomas C. (Ripon, CA); Micali, James V. (Dublin, CA)
Scalar optical beams with helical symmetry
Science Journals Connector (OSTI)
Using a nonorthogonal helical coordinate system, we obtain exact free-space solutions for both the Helmholtz and paraxial Helmholtz equations. At optical frequencies the helical Helmholtz solutions can be interpreted as helical beams characterized by a constant pitch angle and beam radius. These solutions are shown to be generalizations of the family of scalar nondiffracting beams known as Bessel beams. They are similar to Bessel beams in some ways, such as an invariant intensity distribution profile in any plane normal to their axis of propagation, but have a nonconstant order. The paraxial helical Helmholtz equation is cast into two different forms, one assuming propagation along the helical axis and one assuming propagation along the original cylindrical axis. The first is solved using a paraxial form of the above helical beam family while a solution of the second form is a helical Gaussian.
P. L. Overfelt
Rippled beam free electron laser amplifier
A free electron laser amplifier provides a scalloping annular electron beam that interacts with the axial electric field of a TM.sub.0n mode. A waveguide defines an axial centerline and, a solenoid arranged about the waveguide produces an axial constant magnetic field within the waveguide. An electron beam source outputs a annular electron beam that interacts with the axial magnetic field to have an equilibrium radius and a ripple radius component having a variable radius with a ripple period along the axial centerline. An rf source outputs an axial electric field that propagates within the waveguide coaxial with the electron beam and has a radial mode that interacts at the electron beam at the equilibrium radius component of the electron beam.
Carlsten, Bruce E. (Los Alamos, NM)
Plasma-beam interaction in a wiggler
Science Journals Connector (OSTI)
The possibility of obtaining self-bunching of the beam, emission of coherent radiation and strong electrostatic fields in a plasma loaded free electron laser, is studied by means of a set of nonlinear self-consistent equations deduced from the Maxwell equations, the fluid plasma model, and the relativistic equations of motion for the electrons of the beam in the limit of plasma density much larger than the beam density.
V. Petrillo; A. Serbeto; C. Maroli; R. Parrella; R. Bonifacio
Coherence delay augmented laser beam homogenizer
The geometrical restrictions on a laser beam homogenizer are relaxed by ug a coherence delay line to separate a coherent input beam into several components each having a path length difference equal to a multiple of the coherence length with respect to the other components. The components recombine incoherently at the output of the homogenizer, and the resultant beam has a more uniform spatial intensity suitable for microlithography and laser pantogography. Also disclosed is a variable aperture homogenizer, and a liquid filled homogenizer.
Rasmussen, P.; Bernhardt, A.
Electroweak Tests at Beta-beams
We explore the possibility of measuring the Weinberg angle from (anti)neutrino-electron scattering using low energy beta beams, a method that produces single flavour neutrino beams from the beta-decay of boosted radioactive ions. We study how the sensitivity of a possible measurement depends on the intensity of the ion beam and on a combination of different Lorentz boosts of the ions.
A. B. Balantekin; J. H. de Jesus; C. Volpe
Halpha with Heating by Particle Beams
Using 1D NLTE radiative hydrodynamics we model the influence of the particle beams on the Halpha line profile treating the beam propagation and the atmosphere evolution self-consistently. We focus on the influence of the non-thermal collisional rates and the return current. Based on our results, we propose a diagnostic method for determination of the particle beam presence in the formation regions of the Halpha line.
J. Kasparova; M. Varady; M. Karlicky; P. Heinzel; Z. Moravec
Coherence delay augmented laser beam homogenizer
The geometrical restrictions on a laser beam homogenizer are relaxed by ug a coherence delay line to separate a coherent input beam into several components each having a path length difference equal to a multiple of the coherence length with respect to the other components. The components recombine incoherently at the output of the homogenizer, and the resultant beam has a more uniform spatial intensity suitable for microlithography and laser pantogography. Also disclosed is a variable aperture homogenizer, and a liquid filled homogenizer.
Rasmussen, Paul (Livermore, CA); Bernhardt, Anthony (Berkeley, CA)
Stabilization of a Neutral-Beam�Sustained, Mirror-Confined Plasma
Science Journals Connector (OSTI)
We report results of plasma confinement experiments with an auxiliary warm-plasma component flowing along magnetic field lines to suppress ion-cyclotron instabilities. The reduced plasma losses, with the lower fluctuation amplitude, permits neutral-beam build-up of a 13-keV deuterium plasma to densities as high as 4 � 1013 cm-3 corresponding to peak beta values of 0.4. Variation of the beam energy demonstrates that longer confinement times are achieved at higher ion energies.
F. H. Coensgen, W. F. Cummins, B. G. Logan, A. W. Molvik, W. E. Nexsen, T. C. Simonen, B. W. Stallard, and W. C. Turner
The best method of measuring CP violating effect in neutrino oscillation experiments is to construct and use a neutrino beam made of an ideal mixture of $\\bar{\
A. Fukumi; I. Nakano; H. Nanjo; N. Sasao; S. Sato; M. Yoshimura
PowerBeam Inc | Open Energy Information
California Zip: CA 94085 Product: PowerBeam holds the patent to a power transmission technology that produces wireless electricity. Coordinates: 32.780338, -96.547405 Show...
A traveling wave piezoelectric beam robot
Science Journals Connector (OSTI)
In this paper, the operation principles of a traveling wave piezoelectric beam robot are presented. A prototype consisting of an aluminum beam structure, with two non-collocated piezoelectric patches bonded on its surface, was fabricated and tested to demonstrate the generation of a traveling wave on the beam based on the one mode excitation and the two mode excitation operation principles for propulsion. A numerical model was developed and used to study and optimize the generated motion of the piezoelectric beam robot. Experimental characterization of the robot for the two types of operation has been carried out, a comparison between them is made and results are given in this paper.
H Hariri; Y Bernard; A Razek
Molecular Beam Epitaxy, Multi-source | EMSL
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fundamental insight into water splitting for hydrogen... Self-corrected Sensors Based On Atomic Absorption Spectroscopy For Atom Flux Measurements In Molecular Beam Epitaxy. A...
Sandia National Laboratories: ion beam assisted deposition
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ion beam assisted deposition Sandia, Los Alamos, Superconducting Technologies Inc., & Superpower: Solution Deposition Planarization On March 20, 2013, in CINT, Facilities, Grid...
Focused ion beam source method and apparatus
A focused ion beam having a cross section of submicron diameter, a high ion current, and a narrow energy range is generated from a target comprised of particle source material by laser ablation. The method involves directing a laser beam having a cross section of critical diameter onto the target, producing a cloud of laser ablated particles having unique characteristics, and extracting and focusing a charged particle beam from the laser ablated cloud. The method is especially suited for producing focused ion beams for semiconductor device analysis and modification.
Pellin, Michael J. (Naperville, IL); Lykke, Keith R. (Gaithersburg, MD); Lill, Thorsten B. (Sunnyvale, CA)
Yuan T. Lee and Molecular Beam Studies
Office of Scientific and Technical Information (OSTI)
rapidly became a mecca for studies of collision processes. Later, lasers and molecular beams were combined to understand various primary photochemical processes and the...
Probing Organic Transistors with Infrared Beams
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Probing Organic Transistors with Infrared Beams Print Silicon-based transistors are well-understood, basic components of contemporary electronic technology. In contrast, there is...
Science with Beams of Radioactive Isotopes
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2015 The International Chemical Congress of Pacific Basin Societies Science with Beams of Radioactive Isotopes ( 340) Honolulu, Hawaii, USA December 15-20, 2015 Science...
Low-noise macroscopic twin beams
Applying a multiphoton-subtraction technique to two-color macroscopic squeezed vacuum state of light generated via high-gain parametric down conversion we conditionally prepare a new state of light: bright multi-mode low-noise twin beams. The obtained results demonstrate up to 8-fold suppression of noise in each beam while preserving and even moderately improving the nonclassical photon number correlations between the beams. The prepared low-noise macroscopic state, containing up to 2000 photons per mode, is not among the states achievable through nonlinear optical processes. The proposed technique substantially improves the usefulness of twin beams for quantum technologies.
Timur Sh. Iskhakov; Vladyslav C. Usenko; Radim Filip; Maria V. Chekhova; Gerd Leuchs
Beam coupling phenomena have been observed in most fast kicker systems through out Brookhaven Collider-Accelerator complex. With ever-higher beam intensity, the signature of the beam becomes increasingly recognizable. The beam coupling at high intensity produced additional heat dissipation in high voltage modulator, thyratron grids, thyratron driver circuit sufficient to damage some components, and causes trigger instability. In this paper, we will present our observations, basic coupling mode analysis, relevance to the magnet structures, issues related to the existing high voltage modulators, and considerations of the future design of the fast kicker systems.
Beam Characterization at the Neutron Radiography Facility
The quality of a neutron imaging beam directly impacts the quality of radiographic images produced using that beam. Fully characterizing a neutron beam, including determination of the beam�s effective length-to-diameter ratio, neutron flux profile, energy spectrum, image quality, and beam divergence, is vital for producing quality radiographic images. This project characterized the east neutron imaging beamline at the Idaho National Laboratory Neutron Radiography Reactor (NRAD). The experiments which measured the beam�s effective length-to-diameter ratio and image quality are based on American Society for Testing and Materials (ASTM) standards. An analysis of the image produced by a calibrated phantom measured the beam divergence. The energy spectrum measurements consist of a series of foil irradiations using a selection of activation foils, compared to the results produced by a Monte Carlo n-Particle (MCNP) model of the beamline. Improvement of the existing NRAD MCNP beamline model includes validation of the model�s energy spectrum and the development of enhanced image simulation methods. The image simulation methods predict the radiographic image of an object based on the foil reaction rate data obtained by placing a model of the object in front of the image plane in an MCNP beamline model.
Sarah Morgan; Jeffrey King
Study of beam optics and beam halo by integrated modeling of negative ion beams from plasma meniscus formation to beam acceleration
To understand the physical mechanism of the beam halo formation in negative ion beams, a two-dimensional particle-in-cell code for simulating the trajectories of negative ions created via surface production has been developed. The simulation code reproduces a beam halo observed in an actual negative ion beam. The negative ions extracted from the periphery of the plasma meniscus (an electro-static lens in a source plasma) are over-focused in the extractor due to large curvature of the meniscus.
Miyamoto, K. [Naruto University of Education, 748 Nakashima, Takashima, Naruto-cho, Naruto-shi, Tokushima 772-8502 (Japan)] [Naruto University of Education, 748 Nakashima, Takashima, Naruto-cho, Naruto-shi, Tokushima 772-8502 (Japan); Okuda, S.; Hatayama, A. [Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan)] [Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan); Hanada, M.; Kojima, A. [Japan Atomic Energy Agency, 801-1 Mukouyama, Naka 319-0913 (Japan)] [Japan Atomic Energy Agency, 801-1 Mukouyama, Naka 319-0913 (Japan)
Second-order statistical properties of quantum chaotic beams
We consider the situation in which the field of quantum particles such as photons (bosons) or electrons (fermions) undergoes a significant attenuation during the detection process. We characterize the second-order statistical properties of the field by the bunching for bosons and the antibunching for fermions. Bunching and antibunching effects are derived from the time intervals distributions of the random point process of detection instead of the moments of the number of particles registered in a given time interval. Fields of both beams are supposed to be in chaotic states and have second-order time correlation functions of exponential profile and of arbitrary correlation time. A test is proposed for nonclassical states: the behavior of the antibunching function is a nondecreasing function near the origin of the time axis.
Bendjaballah, C.; Pourmir, M. [Laboratoire des Signaux et Systemes, CNRS and Ecole Superieure d'Electricite, 3 rue Joliot-Curie, 91192 Gif-sur-Yvette (France); Departement des Telecommunications, Ecole Superieure d'Electricite, 3 rue Joliot-Curie, 91192 Gif-sur-Yvette (France)
Method and apparatus for laser-controlled proton beam radiology
A proton beam radiology system provides cancer treatment and proton radiography. The system includes an accelerator for producing an H.sup.- beam and a laser source for generating a laser beam. A photodetachment module is located proximate the periphery of the accelerator. The photodetachment module combines the H.sup.- beam and laser beam to produce a neutral beam therefrom within a subsection of the H.sup.- beam. The photodetachment module emits the neutral beam along a trajectory defined by the laser beam. The photodetachment module includes a stripping foil which forms a proton beam from the neutral beam. The proton beam is delivered to a conveyance segment which transports the proton beam to a patient treatment station. The photodetachment module further includes a laser scanner which moves the laser beam along a path transverse to the cross-section of the H.sup.- beam in order to form the neutral beam in subsections of the H.sup.- beam. As the scanning laser moves across the H.sup.- beam, it similarly varies the trajectory of the proton beam emitted from the photodetachment module and in turn varies the target location of the proton beam upon the patient. Intensity modulation of the proton beam can also be achieved by controlling the output of the laser.
Johnstone, Carol J. (Warrenville, IL)
Method and apparatus for laser-controlled proton beam radiology
A proton beam radiology system provides cancer treatment and proton radiography. The system includes an accelerator for producing an H{sup {minus}} beam and a laser source for generating a laser beam. A photodetachment module is located proximate the periphery of the accelerator. The photodetachment module combines the H{sup {minus}} beam and laser beam to produce a neutral beam therefrom within a subsection of the H{sup {minus}} beam. The photodetachment module emits the neutral beam along a trajectory defined by the laser beam. The photodetachment module includes a stripping foil which forms a proton beam from the neutral beam. The proton beam is delivered to a conveyance segment which transports the proton beam to a patient treatment station. The photodetachment module further includes a laser scanner which moves the laser beam along a path transverse to the cross-section of the H{sup {minus}} beam in order to form the neutral beam in subsections of the H{sup {minus}} beam. As the scanning laser moves across the H{sup {minus}} beam, it similarly varies the trajectory of the proton beam emitted from the photodetachment module and in turn varies the target location of the proton beam upon the patient. Intensity modulation of the proton beam can also be achieved by controlling the output of the laser. 9 figs.
Johnstone, C.J.
Simulations of coherent beam-beam effects with head-on compensation
Electron lenses are under construction for installation in RHIC in order to mitigate the head-on beam-beam effects. This would allow operation with higher bunch intensity and result in a significant increase in luminosity. We report on recent strong-strong simulations and experiments that were carried out using the RHIC upgrade parameters to assess the impact of coherent beam-beam effects in the presence of head-on compensation.
White S.; Fischer, W.; Luo. Y.
Cascaded injection resonator for coherent beam combining of laser arrays
The invention provides a cascaded injection resonator for coherent beam combining of laser arrays. The resonator comprises a plurality of laser emitters arranged along at least one plane and a beam sampler for reflecting at least a portion of each laser beam that impinges on the beam sampler, the portion of each laser beam from one of the laser emitters being reflected back to another one of the laser emitters to cause a beam to be generated from the other one of the laser emitters to the beam reflector. The beam sampler also transmits a portion of each laser beam to produce a laser output beam such that a plurality of laser output beams of the same frequency are produced. An injection laser beam is directed to a first laser emitter to begin a process of generating and reflecting a laser beam from one laser emitter to another laser emitter in the plurality. A method of practicing the invention is also disclosed.
Kireev, Vassili [Sunnyvale, CA; Liu, Yun; Protopopescu, Vladimir [Knoxville, TN; Braiman, Yehuda [Oak Ridge, TN
E-Print Network 3.0 - advanced beam dynamics Sample Search Results
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beam-beam interactions with large beam-beam parameter Summary: 1 . The dynamics of the beams could therefore be com- plicated by multimode oscillations of the beam... with...
Optical remote diagnostics of atmospheric propagating beams of ionizing radiation
Data is obtained for use in diagnosing the characteristics of a beam of ionizing radiation, such as charged particle beams, neutral particle beams, and gamma ray beams. In one embodiment the beam is emitted through the atmosphere and produces nitrogen fluorescence during passage through air. The nitrogen fluorescence is detected along the beam path to provide an intensity from which various beam characteristics can be calculated from known tabulations. Optical detecting equipment is preferably located orthogonal to the beam path at a distance effective to include the entire beam path in the equipment field of view.
Karl, Jr., Robert R. (Los Alamos, NM)
Intense Muon Beams for Experiments at Project X
A coherent approach for providing muon beams to several experiments for the intensity-frontier program at Project X is described. Concepts developed for the front end of a muon collider/neutrino factory facility, such as phase rotation and ionization cooling, are applied, but with significant differences. High-intensity experiments typically require high-duty-factor beams pulsed at a time interval commensurate with the muon lifetime. It is challenging to provide large RF voltages at high duty factor, especially in the presence of intense radiation and strong magnetic fields, which may preclude the use of superconducting RF cavities. As an alternative, cavities made of materials such as ultra-pure Al and Be, which become very good �but not super� conductors at cryogenic temperatures, can be used.
C.M. Ankenbrandt, R.P. Johnson, C. Y. Yoshikawa, V.S. Kashikhin, D.V. Neuffer, J. Miller, R.A. Rimmer
Beam Loss Ion Chamber System Upgrade for Experimental Halls
The Beam loss Ion Chamber System (BLICS) was developed to protect Jefferson Labs transport lines, targets and beam dumps from a catastrophic ''burn through''. Range changes and testing was accomplished manually requiring the experiment to be shut down. The new upgraded system is based around an ''off the shelf'' Programmable Logic Controller located in a single control box supporting up to ten individual detectors. All functions that formerly required an entry into the experimental hall and manual adjustment can be accomplished from the Machine Control Center (MCC). A further innovation was the addition of a High Voltage ''Brick'' at the detector location. A single cable supplies the required voltage for the Brick and a return line for the ion chamber signal. The read back screens display range, trip point, and accumulated dose for each location. The new system is very cost effective and significantly reduces the amount of lost experimental time.
D.W. Dotson; D.J. Seidman
Effect of electron beam misalignments on the gyrotron efficiency
The theory describing the operation of gyrotrons with tilted and shifted electron beams has been developed. Effects of the tilt and shift are studied for a 1 MW, 170 GHz gyrotron, which is presently under development in Europe for electron cyclotron resonance plasma heating and current drive in the International Thermonuclear Experimental Reactor. It is shown that one should expect significant deterioration of gyrotron operation in such gyrotrons when the tilt angle exceeds 0.4��0.5� and the parallel shift of the beam axis with respect to the axis of a microwave circuit is larger than 0.4�0.5 mm. At the same time, simultaneous tilting and shifting in a proper manner can mitigate this deteriorating effect.
Dumbrajs, O. [Institute of Solid State Physics, University of Latvia, Kengaraga Street 8, LV-1063 Riga (Latvia)] [Institute of Solid State Physics, University of Latvia, Kengaraga Street 8, LV-1063 Riga (Latvia); Nusinovich, G. S. [Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742-3511 (United States)] [Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742-3511 (United States)
Ionisation Chambers for the LHC Beam Loss Detection
At the Large Hadron Collider (LHC) a beam loss system will be used to prevent and protect superconducting magnets against coil quenches and coil damages. Since the stored particle beam intensity is 8 orders of magnitude larger than the lowest quench level value particular attention is paid to the design of the secondary particle shower detectors. The foreseen ionisation chambers are optimised in geometry simulating the probable loss distribution along the magnets and convoluting the loss distribution with the secondary particle shower distributions. To reach the appropriate coverage of a particle loss and to determine the quench levels with a relative accuracy of 2 the number of the detectors and their lengths is weighted against the particle intensity density variation. In addition attention is paid to the electrical ionisation chamber signal to minimise the ion tail extension. This optimisation is based on time resolved test measurements in the PS booster. A proposal for a new ionisation chamber will be pre...
Gschwendtner, E; Dehning, B; Ferioli, G; Kain, V
Non-dissipative boundary feedback for Rayleigh and Timoshenko beams
Non-dissipative boundary feedback for Rayleigh and Timoshenko beams Chris Guiver and Mark R. Opmeer-dissipative feedback that has been shown in the literature to exponentially stabilize an Euler-Bernoulli beam makes a Rayleigh beam and a Timoshenko beam unstable. 1 Introduction Feedback control of beams is a much studied
Opmeer, Mark
Beam characterization at the Neutron Radiography Reactor
The quality of a neutron-imaging beam directly impacts the quality of radiographic images produced using that beam. Fully characterizing a neutron beam, including determination of the beam's effective length-to-diameter ratio, neutron flux profile, energy spectrum, potential image quality, and beam divergence, is vital for producing quality radiographic images. This paper provides a characterization of the east neutron imaging beamline at the Idaho National Laboratory Neutron Radiography Reactor (NRAD). The experiments which measured the beam's effective length-to-diameter ratio and potential image quality are based on American Society for Testing and Materials (ASTM) standards. An analysis of the image produced by a calibrated phantom measured the beam divergence. The energy spectrum measurements consist of a series of foil irradiations using a selection of activation foils, compared to the results produced by a Monte Carlo n-Particle (MCNP) model of the beamline. The NRAD has an effective collimation ratio greater than 125, a beam divergence of 0.3 +_ 0.1 degrees, and a gold foil cadmium ratio of 2.7. The flux profile has been quantified and the facility is an ASTM Category 1 radiographic facility. Based on bare and cadmium covered foil activation results, the neutron energy spectrum used in the current MCNP model of the radiography beamline over-samples the thermal region of the neutron energy spectrum.
Sarah W. Morgan; Jeffrey C. King; Chad L. Pope
Fast Beam-Based BPM Calibration
The Alignment Diagnostic System (ADS) of the LCLS undulator system indicates that the 33 undulator quadrupoles have extremely high position stability over many weeks. However, beam trajectory straightness and lasing efficiency degrade more quickly than this. A lengthy Beam Based Alignment (BBA) procedure must be executed every two to four weeks to re-optimize the X-ray beam parameters. The undulator system includes RF cavity Beam Position Monitors (RFBPMs), several of which are utilized by an automatic feedback system to align the incoming electron-beam trajectory to the undulator axis. The beam trajectory straightness degradation has been traced to electronic drifts of the gain and offset of the BPMs used in the beam feedback system. To quickly recover the trajectory straightness, we have developed a fast beam-based procedure to recalibrate the BPMs. This procedure takes advantage of the high-precision monitoring capability of the ADS, which allows highly repeatable positioning of undulator quadrupoles. This report describes the ADS, the position stability of the LCLS undulator quadrupoles, and some results of the new recovery procedure.
Bertsche, K.; Loos, H.; Nuhn, H.-D.; Peters, F.; /SLAC
Aerodynamic beam generator for large particles
A new type of aerodynamic particle beam generator is disclosed. This generator produces a tightly focused beam of large material particles at velocities ranging from a few feet per second to supersonic speeds, depending on the exact configuration and operating conditions. Such generators are of particular interest for use in additive fabrication techniques.
Brockmann, John E. (Albuquerque, NM); Torczynski, John R. (Albuquerque, NM); Dykhuizen, Ronald C. (Albuquerque, NM); Neiser, Richard A. (Albuquerque, NM); Smith, Mark F. (Albuquerque, NM)
RESOLVING BEAM TRANSPORT PROBLEMS IN ELECTROSTATIC ACCELERATORS J. D. LARSON (*) Oak Ridge National are frequently encounte- red during the design, operation and upgrading of electrostatic accelerators. Examples are provided of analytic procedures that clarify accelerator ion optics and lead to more effective beam
Boyer, Edmond
On the properties of Circular-Beams
Circular-Beams were introduced as a very general solution of the paraxial wave equation carrying Orbital Angular Momentum. Here we study their properties, by looking at their normalization and their expansion in terms of Laguerre-Gauss modes. We also study their far-field divergence and, for particular cases of the beam parameters, their possible experimental generation.
Giuseppe Vallone
Polymer surface treatment with particle beams
A polymer surface and near surface treatment process produced by irradiation with high energy particle beams. The process is preferably implemented with pulsed ion beams. The process alters the chemical and mechanical properties of the polymer surface in a manner useful for a wide range of commercial applications.
Stinnett, Regan W. (1033 Tramway La. NE., Albuquerque, NM 87122); VanDevender, J. Pace (7604 Lamplighter NE., Albuquerque, NM 87109)
Polymer surface treatment with particle beams
A polymer surface and near surface treatment process produced by irradiation with high energy particle beams is disclosed. The process is preferably implemented with pulsed ion beams. The process alters the chemical and mechanical properties of the polymer surface in a manner useful for a wide range of commercial applications. 16 figs.
Stinnett, R.W.; VanDevender, J.P.
Policy Issues for Retail Beamed Power Transmission
change, (b) the drive to improve air quality, and (c) the need for increased availability of energy solar electric power using retail delivery of beamed power. Recent advances in power beaming have made to enable widespread adoption of this clean and sustainable contribution to meeting energy needs. It is seen
Mikhail Avilov Facility for Rare Isotope Beams
Challenges Chemical Challenges Radiation Challenges Summary #12; World-leading heavy ion accelerator facility for rare isotope science · Nuclear Structure · Nuclear Astrophysics · Fundamental Interactions Target vacuum vessel M. Avilov, May 2014 5th HP Targetry Workshop, FNAL, Slide 4 Target Beam dump Beam
McDonald, Kirk
Nonlinear bending models for beams and plates
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...elastica model when bending does not alter the beam length...linear EB model. If bending does not alter the beam length...procedure is to verify that bending does not alter the plate length...Nauka. 15 Marichev, OI . 1983 Handbook of integral transforms of higher...
Averaged dynamics of ultra-relativisitc charged particles beams
In this thesis, we consider the suitability of using the charged cold fluid model in the description of ultra-relativistic beams. The method that we have used is the following. Firstly, the necessary notions of kinetic theory and differential geometry of second order differential equations are explained. Then an averaging procedure is applied to a connection associated with the Lorentz force equation. The result of this averaging is an affine connection on the space-time manifold. The corresponding geodesic equation defines the averaged Lorentz force equation. We prove that for ultra-relativistic beams described by narrow distribution functions, the solutions of both equations are similar. This fact justifies the replacement of the Lorentz force equation by the simpler {\\it averaged Lorentz force equation}. After this, for each of these models we associate the corresponding kinetic model, which are based on the Vlasov equation and {\\it averaged Vlasov equation} respectively. The averaged Vlasov equation is simpler than the original Vlasov equation. This fact allows us to prove that the differential operation defining the averaged charged cold fluid equation is controlled by the {\\it diameter of the distribution function}, by powers of the {\\it energy of the beam} and by the time of evolution $t$. We show that the Vlasov equation and the averaged Vlasov equation have similar solutions, when the initial conditions are the same. Finally, as an application of the {\\it averaged Lorentz force equation} we re-derive the beam dynamics formalism used in accelerator physics from the Jacobi equation of the averaged Lorentz force equation.
Ricardo Gallego Torrom�
Proton beam on lithium film experiment for the FRIB stripper - Laser
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Engineering Engineering Experimentation > High Power Accelerator Components > Proton beam on lithium film experiment... Capabilities Engineering Experimentation Reactor Safety Testing and Analysis High Power Accelerator Components Proton beam on lithium film experiment for the FRIB stripper Aerosol Experiments System Components Laser Applications Robots Applications Other Facilities Other Capabilities Work with Argonne Contact us For Employees Site Map Help Join us on Facebook Follow us on Twitter NE on Flickr Proton beam on lithium film experiment for the FRIB stripper 1 2 Argonne National Laboratory has developed a liquid lithium charge stripper for use in the Facility for Rare Isotope Beams (FRIB) located at Michigan State University. FRIB will provide intense beams of rare isotopes that can not be handled by ordinary means, creating a challenge to find a workable concept for the charge stripper and to test it in a beamline environment. Argonne's experiment showed, for the first time, the operation of a liquid lithium stripper under realistic conditions of beam-deposited power, and verified that the liquid lithium film was not perturbed by a high power density beam.
Tagged Neutron, Anti-neutron and K-Long beams in an Upgraded MIPP Spectrometer
The MIPP experiment operating with an upgraded data acquisition system will be capable of acquiring data at the rate of 3000 events per second. Currently we are limited to a rate of 30 Hz due to the bottlenecks in the data acquisition electronics of the Time Projection Chamber (TPC). With the speeded up DAQ, MIPP will be capable of acquiring data at the rate of $\\approx$5 million events per day. This assumes a conservative beam duty cycle of 4~sec spill every 2 minutes with a 42% downtime for main injector beam manipulations for the $\\bar{p}$ source. We show that such a setup is capable of producing tagged neutron, anti-neutron and $K^0_L$ beams that are produced in the MIPP cryogenic hydrogen target using proton, anti-proton and $K^{\\pm}$ beams. These tagged beams can be used to study calorimeter responses for use in studies involving the Particle Flow Algorithm (PFA). The energy of these tagged beams will be known to better than 2% on a particle by particle level by means of constrained fitting. We expect a tagged beam rate in the tens of thousands a day. The MIPP spectrometer thus offers a unique opportunity to study the response of calorimeters to neutral particles.
Rajendran Raja
Ion-beam apparatus and method for analyzing and controlling integrated circuits
An ion-beam apparatus and method for analyzing and controlling integrated circuits are disclosed. The ion-beam apparatus comprises a stage for holding one or more integrated circuits (ICs); a source means for producing a focused ion beam; and a beam-directing means for directing the focused ion beam to irradiate a predetermined portion of the IC for sufficient time to provide an ion-beam-generated electrical input signal to a predetermined element of the IC. The apparatus and method have applications to failure analysis and developmental analysis of ICs and permit an alteration, control, or programming of logic states or device parameters within the IC either separate from or in combination with applied electrical stimulus to the IC for analysis thereof. Preferred embodiments of the present invention including a secondary particle detector and an electron floodgun further permit imaging of the IC by secondary ions or electrons, and allow at least a partial removal or erasure of the ion-beam-generated electrical input signal. 4 figs.
Campbell, A.N.; Soden, J.M.
Ion-beam apparatus and method for analyzing and controlling integrated circuits
An ion-beam apparatus and method for analyzing and controlling integrated circuits. The ion-beam apparatus comprises a stage for holding one or more integrated circuits (ICs); a source means for producing a focused ion beam; and a beam-directing means for directing the focused ion beam to irradiate a predetermined portion of the IC for sufficient time to provide an ion-beam-generated electrical input signal to a predetermined element of the IC. The apparatus and method have applications to failure analysis and developmental analysis of ICs and permit an alteration, control, or programming of logic states or device parameters within the IC either separate from or in combination with applied electrical stimulus to the IC for analysis thereof. Preferred embodiments of the present invention including a secondary particle detector and an electron floodgun further permit imaging of the IC by secondary ions or electrons, and allow at least a partial removal or erasure of the ion-beam-generated electrical input signal.
Campbell, Ann N. (Albuquerque, NM); Soden, Jerry M. (Placitas, NM)
Effect of beam limiting aperture and collector potential on multi-element focused ion beams
A compact microwave driven plasma based multi-element focused ion beam system has been developed. In the present work, the effect of reduced beam limiter (BL) aperture on the focused ion beam parameters, such as current and spot size, and a method of controlling beam energy independently by introducing a biased collector at focal point (FP) are investigated. It is found that the location of FP does not change due to the reduction of BL aperture. The location of FP and beam size are found to be weakly dependent on the collector potential in the range from -8 kV to -18 kV.
Paul, Samit; Chowdhury, Abhishek; Bhattacharjee, Sudeep [Department of Physics, Indian Institute of Technology, Kanpur, Uttar Pradesh (India)
Beam Dumping Impedance of the New Beam Screen of the LHC Injection Kicker Magnets
The LHC injection kicker magnets experienced significant beam induced heating of the ferrite yoke, with high beam currents circulating for many hours, during operation of the LHC in 2011 and 2012. The causes of this beam induced heating were studied in depth and an improved beam screen implemented to reduce the impedance. Results of measurements and simulations of the new beam screen design are presented in this paper: these are used to predict power loss for operation after long shutdown 1 and for proposed HL-LHC operational parameters.
Day, H; Caspers, F; M�tral, E; Salvant, B; Uythoven, J
GPU-optimized Code for Long-term Simulations of Beam-beam Effects in Colliders
We report on the development of the new code for long-term simulation of beam-beam effects in particle colliders. The underlying physical model relies on a matrix-based arbitrary-order symplectic particle tracking for beam transport and the Bassetti-Erskine approximation for beam-beam interaction. The computations are accelerated through a parallel implementation on a hybrid GPU/CPU platform. With the new code, a previously computationally prohibitive long-term simulations become tractable. We use the new code to model the proposed medium-energy electron-ion collider (MEIC) at Jefferson Lab.
Roblin, Yves [JLAB; Morozov, Vasiliy [JLAB; Terzic, Balsa [JLAB; Aturban, Mohamed A. [Old Dominion University; Ranjan, D. [Old Dominion University; Zubair, Mohammed [Old Dominion University
Microwave accelerator E-beam pumped laser
A device and method for pumping gaseous lasers by means of a microwave accelerator. The microwave accelerator produces a relativistic electron beam which is applied along the longitudinal axis of the laser through an electron beam window. The incident points of the electron beam on the electron beam window are varied by deflection coils to enhance the cooling characteristics of the foil. A thyratron is used to reliably modulate the microwave accelerator to produce electron beam pulses which excite the laser medium to produce laser pulse repetition frequencies not previously obtainable. An aerodynamic window is also disclosed which eliminates foil heating problems, as well as a magnetic bottle for reducing laser cavity length and pressures while maintaining efficient energy deposition.
Brau, Charles A. (Los Alamos, NM); Stein, William E. (Los Alamos, NM); Rockwood, Stephen D. (Los Alamos, NM)
Carbon Fiber Damage in Particle Beam
Carbon fibers are commonly used as moving targets in beam wire scanners. The heating of the fiber due to energy loss of the particles travelling through is simulated with Geant4. The heating induced by the beam electromagnetic field is estimated with ANSYS. The heat transfer and sublimation processes are modelled. Due to the model nonlinearity, a numerical approach based on discretization of the wire movement is used to solve it for particular beams. Radiation damage to the fiber is estimated with SRIM. The model is tested with available SPS and LEP data and a dedicated damage test on the SPS beam is performed followed by a post-mortem analysis of the wire remnants. Predictions for the LHC beams are made.
Dehning, B; Kroyer, T; Meyer, M; Sapinski, M
Soft beams: when capillarity induces axial compression
We study the interaction of an elastic beam with a liquid drop in the case where bending and extensional effects are both present. We use a variational approach to derive equilibrium equations and constitutive relation for the beam. This relation is shown to include a term due to surface energy in addition of the classical Young's modulus term, leading to a modification of Hooke's law. At the triple point where solid, liquid, and vapor phases meet we find that the external force applied on the beam is parallel to the liquid-vapor interface. Moreover, in the case where solid-vapor and solid-liquid interface energies do not depend on the extension state of the beam, we show that the extension in the beam is continuous at the triple point and that the wetting angle satisfy the classical Young-Dupr\\'e relation.
S�bastien Neukirch; Arnaud Antkowiak; Jean-Jacques Marigo
Beam physics in future electron hadron colliders
High-energy electron-hadron collisions could support a rich research programme in particle and nuclear physics. Several future projects are being proposed around the world, in particular eRHIC at BNL, MEIC at TJNAF in the US, and LHeC at CERN in Europe. This paper will highlight some of the accelerator physics issues, and describe related technical developments and challenges for these machines. In particular, optics design and beam dynamics studies are discussed, including longitudinal phase space manipulation, coherent synchrotron radiation, beam-beam kink instability, ion effects, as well as mitigation measures for beam break up and for space-charge induced emittance growth, all of which could limit the machine performance. Finally, first steps are presented towards an LHeC R&D facility, which should investigate relevant beam-physics processes.
Valloni, A; Klein, M; Schulte, D; Zimmermann, F
Particle beam dynamics | Princeton Plasma Physics Lab
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Particle beam dynamics Particle beam dynamics Subscribe to RSS - Particle beam dynamics The study of the physics of charged particle beams and the accelerators that produce them. This cross-disciplinary area intersects with fields such as plasma physics, high-energy density science, and ultra-fast lasers. Premiere issue of "Quest" magazine details PPPL's strides toward fusion energy and advances in plasma science Quest Magazine Summer 2013 Welcome to the premiere issue of Quest, the annual magazine of the U.S. Department of Energy's Princeton Plasma Physics Laboratory (PPPL). Read more about Premiere issue of "Quest" magazine details PPPL's strides toward fusion energy and advances in plasma science Ronald C Davidson Ronald Davidson heads PPPL research on charged particle beam dynamics and
Deep Beams and Slabs The purpose of skin reinforcement in a deep beam is to limit the
Deep Beams and Slabs Deep Beams The purpose of skin reinforcement in a deep beam is to limit require different amounts of skin reinforcement. The purpose of our experiment is to compare beams designed with the different amounts of skin reinforcement required by these codes. 3 deep beams following
Barthelat, Francois
E-Print Network 3.0 - average beam power Sample Search Results
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at target, trajectory (M) Screen positions (M... S. Childress -- Proton BeamsProton Beams 1616 Main Injector Beam Power 2008Main Injector Beam Power 2008 Main... ... Source:...
Implementation of Accelerated Beam-Specific Matched-Filter-Based Optical Alignment
Accurate automated alignment of laser beams in the National Ignition Facility (NIF) is essential for achieving extreme temperature and pressure required for inertial confinement fusion. The alignment achieved by the integrated control systems relies on algorithms processing video images to determine the position of the laser beam images in real-time. Alignment images that exhibit wide variations in beam quality require a matched-filter algorithm for position detection. One challenge in designing a matched-filter based algorithm is to construct a filter template that is resilient to variations in imaging conditions while guaranteeing accurate position determination. A second challenge is to process the image as fast as possible. This paper describes the development of a new analytical template that captures key recurring features present in the beam image to accurately estimate the beam position under good image quality conditions. Depending on the features present in a particular beam, the analytical template allows us to create a highly tailored template containing only those selected features. The second objective is achieved by exploiting the parallelism inherent in the algorithm to accelerate processing using parallel hardware that provides significant performance improvement over conventional processors. In particular, a Xilinx Virtex II Pro FPGA hardware implementation processing 32 templates provided a speed increase of about 253 times over an optimized software implementation running on a 2.0 GHz AMD Opteron core.
Awwal, A S; Rice, K L; Taha, T M
H-mode accelerating structures with permanent-magnet quadrupole beam focusing
We have developed high-efficiency normal-conducting rf accelerating structures by combining H -mode resonator cavities and a transverse beam focusing by permanent-magnet quadrupoles (PMQ), for beam velocities in the range of a few percent of the speed of light. The shunt impedance of interdigital H -mode (IH-PMQ) structures is 10�20 times higher than that of a conventional drift-tube linac, while the transverse size is 4�5 times smaller. Results of the combined 3D modeling�electromagnetic computations, multiparticle beam-dynamics simulations with high currents, and thermal-stress analysis�for an IH-PMQ accelerator tank are presented. The accelerating-field profile in the tank is tuned to provide the best propagation of a 50-mA deuteron beam using coupled iterations of electromagnetic and beam-dynamics modeling. Measurements of a cold model of the IH-PMQ tank show a good agreement with the calculations. Examples of cross-bar H -mode structures with PMQ focusing for higher beam velocities are also presented. H -PMQ accelerating structures following a short radio-frequency quadrupole accelerator can be used both in the front end of ion linacs or in stand-alone applications.
Kurennoy, S. S.; Rybarcyk, L. J.; O�Hara, J. F.; Olivas, E. R.; Wangler, T. P.
Trigger probe for determining the orientation of the power distribution of an electron beam
The present invention relates to a probe for determining the orientation of electron beams being profiled. To accurately time the location of an electron beam, the probe is designed to accept electrons from only a narrowly defined area. The signal produced from the probe is then used as a timing or triggering fiducial for an operably coupled data acquisition system. Such an arrangement eliminates changes in slit geometry, an additional signal feedthrough in the wall of a welding chamber and a second timing or triggering channel on a data acquisition system. As a result, the present invention improves the accuracy of the resulting data by minimizing the adverse effects of current slit triggering methods so as to accurately reconstruct electron or ion beams.
Elmer, John W. (Danville, CA); Palmer, Todd A. (Livermore, CA); Teruya, Alan T. (Livermore, CA)
Transverse resistive wall effects on the dynamics of a bunched electron beam
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In the wigglers of future free-electron lasers, the electron beam will be required to travel over a length of 10 m or more in pipes with small diameters. Transverse resistive wall effects could lead to beam breakup during this transport. To investigate this possibility, the equation of motion for a bunched beam is solved analytically. Results show that a steady-state solution is reached for times larger than the diffusion time. This solution can either oscillate or grow exponentially with the length of the pipe, depending on the relative magnitudes of the resistive wall effect and the focusing force in the wiggler. The magnitude of the resistive wall effect depends on the pipe radius b (it increases as 1/b2) but is independent of the thickness and conductivity of the pipe. The thickness and conductivity affect only the time required to reach the steady-state solution. The possibility of a significant transient is also discussed.
Govindan Rangarajan and K. C. D. Chan
World record neutron beam at Los Alamos National Laboratory
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World record neutron beam at LANL World record neutron beam at Los Alamos National Laboratory Scientists have created the largest neutron beam ever made by a short-pulse laser,...
Interference of a pair of symmetric partially coherent beams
optical effects; (140.3300) Laser beam shaping; (350.5500)of symmetric Collett-Wolf beams,� Opt. Lett. 30, 1605�1607 (of highly directional light beams? �, Opt. Lett. 2, 27�29 (
Garc?a-Guerrero, E. E.; Mendez, E. R.; Gu, Zu-Han; Leskova, T. A.; Maradudin, A. A.
Microsoft Word - LCC-0135 Machine Protection Issues in the Beam Delivery System.doc
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5 5 SLAC-TN-04-039 November 2003 Abstract This note documents a set of expressions used to explore the issue of whether or not it is reasonable to consider a conventional positron source for a Tesla formatted beam. The critical issue is that of energy deposition in the conversion target and the comparison of the induced stress with the ultimate tensile strength of the target material. Since the length of the incident beam pulse is large in comparison to the ratio of beam size to the speed of sound, the concurrent pressure pulse dissipates in a time short compared to the overall pulse duration and one is left with only the Machine Protection Issues in the Beam Delivery System L. Keller and T. Markiewicz Stanford Linear Accelerator Center
10 MW/sub e/ Solar Thermal Central Receiver Pilot Plant heliostat and beam characterization system evaluation, November 1981-December 1986
Test and evaluation results for the heliostats and beam characterization system at the 10 MW/sub e/ Solar Thermal Central Receiver Pilot Plant are described in this report. Southern California Edison operated and maintained the plant during the five years covered by this evaluation. Therefore, the results represent what can be expected from a large number of heliostats that are operated over a long period of time in a power plant environment. The heliostats and beam characterization system were evaluated for their ability to meet performance and survival requirements. Heliostat evaluation results are reported for mirror soiling rates, mirror corrosion, wind loads, availability, maintenance requirements, tracking accuracy, beam quality, component temperatures, and operating power requirements. The heliostat beam characterization system accuracy is given for the measurement of beam quality, heliostat tracking accuracy, and power in the reflected beam. The heliostat technical specifications and design description are provided, and a detailed design description of the beam characterization system is included. 41 refs.
Mavis, C.L.
Rf beam control for the AGS Booster
RF beam control systems for hadron synchrotrons have evolved over the past three decades into an essentially standard design. The key difference between hadron and lepton machines is the absence of radiation damping and existence of significant frequency variation in the case of hadrons. Although the motion of the hadron in the potential well of the rf wave is inherently stable it is not strongly damped. Damping must be provided by electronic feedback through the accelerating system. This feedback is typically called the phase loop. The technology of the rf beam control system for the AGS Booster synchrotron is described. First, the overall philosophy of the design is explained in terms of a conventional servo system that regulates the beam horizontal position in the vacuum chamber. The concept of beam transfer functions is fundamental to the mathematics of the design process and is reviewed. The beam transfer functions required for this design are derived from first principles. An overview of the beam signal pick-ups and high level rf equipment is given. The major subsystems, the frequency program, the heterodyne system, and beam feedback loops, are described in detail. Beyond accelerating the beam, the rf system must also synchronize the bunches in the Booster to the buckets in the AGS before transfer. The technical challenge in this process is heightened by the need to accomplish synchronization while the frequency is still changing. Details of the synchronization system are given. This report is intended to serve two purposes. One is to document the hardware and performance of the systems that have been built. The other is to serve as a tutorial vehicle from which the non-expert can not only learn the details of this system but also learn the principles of beam control that have led to the particular design choices made.
Brennan, J.M.
Physics with Rare Isotope Beams
Using stable and radioactive beams provided by ATLAS nuclear reactions of special interest in astrophysics have been studied with emphasis on breakout from the hot CNO cycle to the rp-process. The masses of nuclear fragments provided by a strong fission source have been measured in order to help trace the path of the r process. 8Li ions produced by the d(7Li,8Li)n reaction have been trapped and the electrons and alphas emitted in the ensuing beta-decay measured. The neutrino directions were therefore determined, which leads to a measurement of the electron-neutrino correlation. The energies and kinematics are such that a sensitive search for any tensor admixture could be performed and an upper limit of 0.6% was placed on any such admixture. Earlier work on the electromagnetic form factors of the proton was extended. Graduate students were active participants in all of these eperiments, which formed the basis for six PhD theses.
Segel, Ralph E. [Northwestern University] [Northwestern University
Monte Carlo Modeling of Ion Beam Induced Secondary Electrons.
??Modeling ion beam induced secondary electron (iSE) production within matter for simulating ion beam induced images has been studied. When the complex nature of ion� (more)
Huh, Uk
Measuring Tiny Waves with High Power Particle Beams | Princeton...
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Measuring Tiny Waves with High Power Particle Beams American Fusion News Category: U.S. Universities Link: Measuring Tiny Waves with High Power Particle Beams...
Structural Modification of Nanocrystalline Ceria by Ion Beams...
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Modification of Nanocrystalline Ceria by Ion Beams. Structural Modification of Nanocrystalline Ceria by Ion Beams. Abstract: Using energetic ions, we have demonstrated effective...
Long Plasma Source for Heavy Ion Beam Charge Neutralization
neutralizing plasma column the heavy ion beam can focus to aPlasmas are a source of unbound electrons for charge neutralizing intense heavy ion beams to focus
Efthimion, P.C.
Beam manipulation by self-wakefield at ATF
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Committee and the ATF Users' Meetings, April 26 - 27, 2012 Outline 1. Enhanced Transformer Ratio demonstration (wakefield mapping with the shaped beam) 2. Tunable beam energy...
Applications of High Energy Ion Beam Techniques in Environmental...
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High Energy Ion Beam Techniques in Environmental Science: Investigation Associated with Glass and Ceramic Waste Applications of High Energy Ion Beam Techniques in Environmental...
Beyond ITER: Neutral beams for DEMO
In the development of magnetically confined fusion as an economically sustainable power source, ITER is currently under construction. Beyond ITER is the DEMO programme in which the physics and engineering aspects of a future fusion power plant will be demonstrated. DEMO will produce net electrical power. The DEMO programme will be outlined and the role of neutral beams for heating and current drive will be described. In particular, the importance of the efficiency of neutral beam systems in terms of injected neutral beam power compared to wallplug power will be discussed. Options for improving this efficiency including advanced neutralisers and energy recovery are discussed.
McAdams, R
Beam Stability: Benefits from Concentrating on Basics
In recent years there has been a lot of activity aimed at producing smaller and more intense beams. However, experience has shown that with these beams the quality of the data obtained is highly sensitive to alignment issues, mechanical (in)stabilities, source instabilities, material choices and surface degradations of optical components. Over several years the ESRF has investigated many beamline optical components with the view to improve both beam and sample stability. The measures that have been taken to achieve these improvements are described together with possible improvements that could be envisaged in the future.
Mairs, T. R.; Mathon, O. [European Synchrotron Radiation Facility, BP220, 38043 Grenoble (France)
Discontinuous Buckling of Wide Beams and Metabeams
We uncover how nonlinearities dramatically influence the buckling of elastic beams by means of experiments, simulations and theory. We show that sufficiently wide, ordinary elastic beams exhibit discontinuous buckling, an unstable form of buckling where the post-buckling stiffness is negative. We develop a 1D model that matches our data and identify nonlinearity as the main cause for negative stiffness. Finally, we create nonlinear metamaterials that allow us to rationally design the (negative) post-buckling stiffness of metabeams, independently of beam thickness, and demonstrate discontinuous buckling for metabeams as slender as 1% numerically and 5% experimentally.
Corentin Coulais; Johannes T. B. Overvelde; Luuk A. Lubbers; Katia Bertoldi; Martin van Hecke
Coating thermal noise for arbitrary shaped beams
Advanced LIGO's sensitivity will be limited by coating noise. Though this noise depends on beam shape, and though nongaussian beams are being seriously considered for advanced LIGO, no published analysis exists to compare the quantitative thermal noise improvement alternate beams offer. In this paper, we derive and discuss a simple integral which completely characterizes the dependence of coating thermal noise on shape. The derivation used applies equally well, with minor modifications, to all other forms of thermal noise in the low-frequency limit.
Richard O'Shaughnessy
Fusion Induced by Radioactive Ion Beams
The use of radioactive beams opens a new frontier for fusion studies. The coupling to the continuum can be explored with very loosely bound nuclei. Experiments were performed with beams of nuclei at or near the proton and neutron drip-lines to measure fusion and associated reactions in the vicinity of the Coulomb barrier. In addition, the fusion yield is predicted to be enhanced in reactions involving very neutron-rich unstable nuclei. Experimental measurements were carried out to investigate if it is feasible to use such beams to produce new heavy elements. The current status of these experimental activities is given in this review.
J. F. Liang; C. Signorini
Intense steady state electron beam generator
An intense, steady state, low emittance electron beam generator is formed by operating a hollow cathode discharge plasma source at critical levels in combination with an extraction electrode and a target electrode that are operable to extract a beam of fast primary electrons from the plasma source through a negatively biased grid that is critically operated to repel bulk electrons toward the plasma source while allowing the fast primary electrons to move toward the target in the desired beam that can be successfully transported for relatively large distances, such as one or more meters away from the plasma source.
Hershcovitch, Ady (Mount Sinai, NY); Kovarik, Vincent J. (Bohemia, NY); Prelec, Krsto (Setauket, NY)
Press Pass - Press Release - U.S. LHC first beam
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8-15 8-15 Aug. 8, 2008 For immediate release Media Contacts: Brookhaven National Laboratory - Kendra Snyder, firstname.lastname@example.com, 631-344-8191 Fermilab - Judy Jackson, 630-840-3351, firstname.lastname@example.com Lawrence Berkeley National Laboratory - Dan Krotz, email@example.com, (510) 486-4019 and Paul Preuss, firstname.lastname@example.com, 510-486-6249 CERN - James Gillies, firstname.lastname@example.com, +41 22 767 4101 Photos and graphics of the Large Hadron Collider are available at: http://multimedia-gallery.web.cern.ch/multimedia-gallery/PhotoGallery_Main.aspx and http://www.uslhc.us/Images. U.S. scientists count down to LHC startup Batavia, IL, Berkeley, CA and Upton, NY - On September 10, scientists at the Large Hadron Collider will attempt for the first time to send a proton beam zooming around the 27-kilometer-long accelerator. The LHC, the world's most powerful particle accelerator, is located at CERN in Geneva, Switzerland. Journalists are invited to attend LHC first beam events at CERN and several locations within the United States. Information about the CERN event and accreditation procedures is available at . A list of LHC startup events in the U.S. and contact information for each is available at http://www.uslhc.us/first_beam.
Low Beam Voltage, 10 MW, L-Band Cluster Klystron
Conceptual design of a multi-beam klystron (MBK) for possible ILC and Project X applications is presented. The chief distinction between this MBK design and existing 10-MW MBK's is the low operating voltage of 60 kV. There are at least four compelling reasons that justify development at this time of a low-voltage MBK, namely (1) no pulse transformer; (2) no oil tank for high-voltage components and for the tube socket; (3) no high-voltage cables; and (4) modulator would be a compact 60-kV IGBT switching circuit. The proposed klystron consists of four clusters containing six beams each. The tube has common input and output cavities for all 24 beams, and individual gain cavities for each cluster. A closely related optional configuration, also for a 10 MW tube, would involve four totally independent cavity clusters with four independent input cavities and four 2.5 MW output ports, all within a common magnetic circuit. This option has appeal because the output waveguides would not require a controlled atmosphere, and because it would be easier to achieve phase and amplitude stability as required in individual SC accelerator cavities.
Teryaev, V.; /Novosibirsk, IYF; Yakovlev, V.P.; /Fermilab; Kazakov, S.; /KEK, Tsukuba; Hirshfield, J.L.; /Yale U. /Omega-P, New Haven
Low-coherence doppler lidar with multiple time coherence of reference and probe waves
Science Journals Connector (OSTI)
The notion of multiple time coherence of optical beams is introduced and mathematically ... pulses (MFPs), which exhibit multiple time coherence, and the possibility of their application for ... is based on nanos...
G. G. Matvienko; S. N. Polyakov; V. K. Oshlakov
Signal processing for longitudinal parameters of the Tevatron beam
We describe the system known as the Tevatron SBD [1] which is used to provide information on the longitudinal parameters of coalesced beam bunches in the Tevatron. The system has been upgraded over the past year with a new digitizer and improved software. The quantities provided for each proton and antiproton bunch include the intensity, the longitudinal bunch profile, the timing of the bunch with respect to the low-level RF, the momentum spread and the longitudinal emittance. The system is capable of 2 Hz operation and is run at 1 Hz.
Pordes, S.; Crisp, J.; Fellenz, B.; Flora, R.; Para, A.; Tollestrup, A.V.; /Fermilab
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Digestion time Digestion time Name: Don Mancosh Location: N/A Country: N/A Date: N/A Question: I have always given the rule of thumb in class that material we eat is with us for about 24 hours before exiting the body. The question arises about the time value of liquids. Getting a big coke prior to a 3 hour drive generally means that there will be a stop along the way. Is there a generalization made about liquids in the body similar to the one for solid food? Replies: A physician would give a better answer, but I hazard this: the only liquids which people consume (deliberately) in significant quantities are water, ethyl alcohol and various oils. Water and alcohol are absorbed on a time scale of seconds to minutes through the mouth, stomach and digestive tract. The oils are huge molecules, so I'd guess like any other greasy food they get absorbed in the upper digestive tract. Some of them, perhaps the longest and most nonpolar, are not absorbed at all --- cf. the old-time remedy of mineral oil for constipation --- so there should be some average time-before-what's-left-is-excreted such as you're looking for, and my (wild) guess is that it would not differ substantially from that for food. You can define an average lifetime in the body for alcohol, since the natural level is zero. Rough guidelines are widespread in the context of drunk driving laws. But this is not really possible for water. One's body is normally full up to the brim with water, and there's no way for the body to distinguish between water molecules recently absorbed and molecules that've been moping around since the Beatles split up. Thus the water entering the toilet bowl after the pit stop is not in general the same water as was in the big coke. If you were to consider for water just the average time between drinking and peeing, it would seem to depend strongly on how well hydrated the body was before the drink, and how much was drunk. During sustained heavy exertion in the sun and dry air one can easily drink a pint of water an hour without peeing at all. On the other hand, if one is willing to drink enough water fast enough, so as to establish a high excess of body water one can pee 8 ounces 15 minutes or less after drinking 8 ounces.
The Radioactive Beam Program at Argonne
In this talk I will present selected topics of the ongoing radioactive beam program at Argonne and discuss the capabilities of the CARIBU radioactive ion production facility as well as plans for construction of a novel superconducting solenoid spectrometer.
B. B. Back
14th international symposium on molecular beams
This report discusses research being conducted with molecular beams. The general topic areas are as follows: Clusters I; reaction dynamics; atomic and molecular spectroscopy; clusters II; new techniques; photodissociation dynamics; and surfaces.
Not Available
14th international symposium on molecular beams
This report discusses research being conducted with molecular beams. The general topic areas are as follows: Clusters I; reaction dynamics; atomic and molecular spectroscopy; clusters II; new techniques; photodissociation & dynamics; and surfaces.
Not Available
Object-Oriented Modelling of Flexible Beams
Science Journals Connector (OSTI)
In this paper the problem of modelling flexible thin beams in multibody systems is tackled. The proposed model, implemented with the object-oriented modelling language Modelica, is completely modular, allowing th...
Francesco Schiavo; Luca Vigan�; Gianni Ferretti
Cryogenic Electron Beam Induced Chemical Etching
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Cryogenic cooling is used to enable efficient, gas-mediated electron beam induced etching (EBIE) in cases where the etch rate is negligible at room and elevated substrate temperatures. The process is demonstrated using nitrogen trifluoride (NF3) as the ...
Aiden A. Martin; Milos Toth
A method and an apparatus for forming a charge neutral ion beam which is useful in producing thin films of material on electrically conductive or non-conductive substrates are provided. 4 figs.
Springer, R.W.
Accelerated Radioactive Nuclear Beams (Low Energy)
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The possibility of producing and accelerating intense beams of short-lived radioactive heavy ions, both for studies of nuclides themselves and for use as projectiles in reactions of considerable interest to the f...
John M. D�Auria
High-Power Laser Beam Cladding
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This paper reports major advances in the understanding, refinement and application of high-power laser beam cladding. The most important relationships between essential laser process variables and clad characteri...
G. J. Bruck
The Electron Beam Ion Source (EBIS)
Brookhaven National Lab has successfully developed a new pre-injector system, called the Electron Beam Ion Source, for the Relativistic Heavy Ion Collider (RHIC) and NASA Space Radiation Laboratory science programs. The first of several planned improvemen
Brookhaven Lab
A Micromachined Electron Beam Ion Source
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The complete ion source consists of two parts: an RF-plasma electron source, the linked up optic which focuses the electron beam into the second part, the ionization...
G. Petzold; P. Siebert; J. M�ller
The Electron Beam Ion Source (EBIS)
Brookhaven National Lab has successfully developed a new pre-injector system, called the Electron Beam Ion Source, for the Relativistic Heavy Ion Collider (RHIC) and NASA Space Radiation Laboratory science programs. The first of several planned improvemen
Brookhaven Lab
Doublet III neutral beam power system
The Doublet III neutral beam power system supplies pulsed power to the neutral beam injectors for plasma heating experiments on the Doublet III tokamak. The power supply system is connected to an ion source where the power is converted to an 80 kV, 80A, 0.5 sec beam of hydrogen ions at maximum power output. These energetic ions undergo partial neutralization via charge exchange in the beamline. The energetic neutral hydrogen atoms pass through the Doublet III toroidal and poloidal magnet fields and deposit their energy in the confined plasma. The unneutralized ions are deflected into a water-cooled dump. The entire system is interfaced through the neutral beam computer instrumentation and control system.
Nerem, A.; Beal, J.W.; Colleraine, A.P.; LeVine, F.H.; Pipkins, J.F.; Remsen, D.B. Jr.; Tooker, J.F.; Varga, H.J.; Franck, J.V.
SolBeam Inc | Open Energy Information
California Zip: 92677 Product: California-based startup developing concentrator photovoltaics. References: SolBeam Inc1 This article is a stub. You can help OpenEI by...
The Spallation Neutron Source (SNS) at the Oak Ridge National Laboratory (ORNL) provides variable energy neutrons for a variety of experiments. The neutrons proceed down beam lines to the experiment hall, which houses a variety of experiments and test articles. Each beam line has one or more neutron choppers which filter the neutron beam based on the neutron energy by using a rotating neutron absorbing material passing through the neutron beam. Excessive vibration of the Vision beam line, believed to be caused by the T0 chopper, prevented the Vision beam line from operating at full capacity. This problem had been addressed several times by rebalancing/reworking the T0 beam chopper but the problem stubbornly persisted. To determine the cause of the high vibration, dynamic testing was performed. Twenty-seven accelerometer and motor current channels of data were collected during drive up, drive down, coast down, and steady-state conditions; resonance testing and motor current signature analysis were also performed. The data was analyzed for traditional mechanical/machinery issues such as misalignment and imbalance using time series analysis, frequency domain analysis, and operating deflection shape analysis. The analysis showed that the chopper base plate was experiencing an amplified response to the excitation provided by the T0 beam chopper. The amplified response was diagnosed to be caused by higher than expected base plate flexibility, possibly due to improper grouting or loose floor anchors. Based on this diagnosis, a decision was made to dismantle the beam line chopper and remount the base plate. Neutron activation of the beam line components make modifications to the beam line especially expensive and time consuming due to the radiation handling requirements, so this decision had significant financial and schedule implications. It was found that the base plate was indeed loose because of improper grouting during its initial installation. The base plate was modified by splitting it into multiple sections, isolating the T0 chopper from the rest of the beam line, and each section was then reinstalled and re-grouted. After these modifications, the vibration levels were reduced by a factor of 30. The reduction in vibration level was sufficient to allow the Vision beam line to operate at full capacity for the first time since its completed construction date.
Van Hoy, Blake W [ORNL
Beam Coupling to Optical Scale Accelerating Structures
Current research efforts into structure based laser acceleration of electrons utilize beams from standard RF linacs. These beams must be coupled into very small structures with transverse dimensions comparable to the laser wavelength. To obtain decent transmission, a permanent magnet quadrupole (PMQ) triplet with a focusing gradient of 560 T/m is used to focus into the structure. Also of interest is the induced wakefield from the structure, useful for diagnosing potential accelerator structures or as novel radiation sources.
Sears, C.M.; Byer, R.L.; Colby, E.R.; Cowan, B.M.; Ischebeck, R.; Lincoln, M.R.; Siemann, R.H.; Spencer, J.E.; /SLAC; Plettner, T.; /Stanford U., Phys. Dept.
Beam Coupling to Optical Scale Accelerating Structures
Current research efforts into structure based laser acceleration of electrons utilize beams from standard RF linacs. These beams must be coupled into very small structures with transverse dimensions comparable to the laser wavelength. To obtain decent transmission, a permanent magnet quadrupole (PMQ) triplet with a focusing gradient of 560 T/m is used to focus into the structure. Also of interest is the induced wakefield from the structure, useful for diagnosing potential accelerator structures or as novel radiation sources.
Sears, Christopher M. S.; Colby, Eric R.; Cowan, Benjamin M.; Ischebeck, Rasmus; Lincoln, Melissa R.; Siemann, Robert H.; Spencer, James E. [Stanford Linear Accelerator Center, Menlo Park, CA 94025 (United States); Byer, Robert L.; Plettner, Tomas [Stanford University, Stanford, CA 94305 (United States)
Ion beam processing of advanced electronic materials
This report contains research programs discussed at the materials research society symposia on ion beam processing of advanced electronic materials. Major topics include: shallow implantation and solid-phase epitaxy; damage effects; focused ion beams; MeV implantation; high-dose implantation; implantation in III-V materials and multilayers; and implantation in electronic materials. Individual projects are processed separately for the data bases. (CBS)
Cheung, N.W.; Marwick, A.D.; Roberto, J.B. (eds.) (California Univ., Berkeley, CA (USA); International Business Machines Corp., Yorktown Heights, NY (USA). Thomas J. Watson Research Center; Oak Ridge National Lab., TN (USA))
A numerical approach to beam deflections
to Beam Deflections. (December 1974) Joel Ernest Lovell, B. S. , Texas ASM University Chairman of Advisory Committee: Prof. E. S. Holdr edge A numerical method for determining deflections of canti- lever and simply supported beams directly from their M/EI... de- flections due to shear is solvable analytically for many types of loadings and cross sectional variations. However, the solution of the equation is cumbersome for any situations where M/EI cannot be described as a continuous function of length...
Lovell, Joel Ernest
Beam dumping system and abort gap
The performance of the beam dumping systems and the abort gap cleaning are reviewed in the context of the general machine protection system. Details of the commissioning experience and setting up, encountered equipment problems, the experience with and status of the eXternal Post Operational Checks (XPOC) and the importance of operational procedures are presented for the beam dumping system. The brief experience with the abort gap cleaning is also presented.
Uythoven, J
Electron Beam Pasteurization of Fresh Fruit for Neutropenic Diet: E-beam Reduces Bioburden While Preserving Quality
encouragement and assistance whenever it was needed. I also want to give a special thanks Mickey and Kayla at the National Center for Electron Beam Research Center whom kindly assisted me with irradiating my samples. Thanks also to Dr. Patil for allowing... me to use his lab to perform many experiments for which would be impossible without them. Special thanks to Ram Uckoo and Dr. J.K. for teaching and guiding me throughout my time there. I am very grateful to Tom Jondiko in Dr. Awika?s lab...
Smith, Bianca R
Development of mass spectrometry by high energy focused heavy ion beam: MeV SIMS with 8 MeV Cl7+ beam
Science Journals Connector (OSTI)
Abstract Particle induced X-ray emission (PIXE) at microprobe of Jo�ef Stefan Institute is used to measure two-dimensional quantitative elemental maps of biological tissue. To improve chemical and biological understanding of the processes in vivo, supplementary information about chemical bonding and/or molecular distributions could be obtained by heavy-ion induced molecular desorption and a corresponding mass spectroscopy with Time-Of-Flight (TOF) mass spectrometer. As the method combines the use of heavy focused ions in MeV energy range and TOF Secondary Ion Mass Spectrometry, it is denoted as MeV SIMS. At Jo�ef Stefan Institute, we constructed a linear TOF spectrometer and mount it to our multipurpose nuclear microprobe. A beam of 8�MeV 35Cl7+ could be focused to a diameter of better than 3�?m�נ3�?m and pulsed by electrostatic deflection at the high-energy side of accelerator. TOF mass spectrometer incorporates an 1�m long drift tube and a double stack microchannel plate (MCP) as a stop detector positioned at the end of the drift path. Secondary ions are focused at MCP using electrostatic cylindrical einzel lens. Time of flight spectra are currently acquired with a single-hit time-to-digital converter. Pulsed ion beam produces a shower of secondary ions that are ejected from positively biased target and accelerated towards MCP. We start our time measurement simultaneously with the start of the beam pulse. Signal of the first ion hitting MCP is used to stop the time measurement. Standard pulses proportional to the time of flight are produced with time to analog converter (TAC) and fed into analog-to-digital converter to obtain a time histogram. To enable efficient detection of desorbed fragments with higher molecular masses, which are of particular interest, we recently implemented a state-of art Field Programmable Gate Array (FPGA)-based multi-hit TOF acquisition. To test the system we used focused 8�MeV 35Cl7+ ion beam with pulse length of 180�ns. Mass resolution of measured SIMS spectra, dominantly determined by the duration of the beam pulse, is in good agreement with resolution estimated from pulse length. With improved high-voltage switching ability that will enable beam pulses with duration of 50�ns, a mass resolution of better than 500 is anticipated.
Luka Jeromel; Zdravko Siketi?; Nina Ogrinc Poto?nik; Primo� Vavpeti?; Zdravko Rupnik; Klemen Bu?ar; Primo� Pelicon
E-Print Network 3.0 - atomic oxygen beams Sample Search Results
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beams Search Powered by Explorit Topic List Advanced Search Sample search results for: atomic oxygen beams...
E-Print Network 3.0 - atomic oxygen beam Sample Search Results
NLE Websites -- All DOE Office Websites (Extended Search)
beam Search Powered by Explorit Topic List Advanced Search Sample search results for: atomic oxygen beam...
Indirect drive experiments utilizing multiple beam cones in cylindrical hohlraums on OMEGA
Current plans for time-dependent control of flux asymmetry in the National Ignition Facility [J. A. Paisner, J. D. Boyes, S. A. Kumpan, and M. Sorem, {open_quotes}The National Ignition Facility Project,{close_quotes} ICF Quart. {bold 5}, 110 (1995)] hohlraums rely on multiple beam cones with different laser power temporal profiles in each cone. Experiments with multiple beam cones have begun on the Omega laser facility [T. R. Boehly {ital et al.}, Opt. Commun. {bold 133}, 495 (1997)] at the University of Rochester. In addition to allowing symmetry experiments similar to those performed on Nova [A. Hauer {ital et al.}, Rev. Sci. Instrum. {bold 66}, 672 (1995)], the Omega facility allows multiple beam cones to be moved independently to confirm our ability to model the resulting implosion image shapes. Results indicate that hohlraum symmetry behaves similarly with multiple rings of beams as with a single ring, but with the weighted beam spot position used to parametrize the beam pointing.
Murphy, T.J.; Wallace, J.M.; Delamater, N.D.; Barnes, C.W.; Gobby, P.; Hauer, A.A.; Lindman, E.L.; Magelssen, G.; Moore, J.B.; Oertel, J.A.; Watt, R. [Los Alamos National Laboratory, Los Alamos, New Mexico87545 (United States)] [Los Alamos National Laboratory, Los Alamos, New Mexico87545 (United States); Landen, O.L.; Amendt, P.; Cable, M.; Decker, C.; Hammel, B.A.; Koch, J.A.; Suter, L.J.; Turner, R.E.; Wallace, R.J. [Lawrence Livermore National Laboratory, Livermore, California94550 (United States)] [Lawrence Livermore National Laboratory, Livermore, California94550 (United States); Marshall, F.J.; Bradley, D.; Craxton, R.S.; Keck, R.; Knauer, J.P.; Kremens, R.; Schnittman, J.D. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York14627 (United States)] [Laboratory for Laser Energetics, University of Rochester, Rochester, New York14627 (United States)
Flyer Acceleration by Pulsed Ion Beam Ablation and Application for Space Propulsion
Flyer acceleration by ablation plasma pressure produced by irradiation of intense pulsed ion beam has been studied. Acceleration process including expansion of ablation plasma was simulated based on fluid model. And interaction between incident pulsed ion beam and a flyer target was considered as accounting stopping power of it. In experiments, we used ETIGO-II intense pulsed ion beam generator with two kinds of diodes; 1) Magnetically Insulated Diode (MID, power densities of <100 J/cm2) and 2) Spherical-focused Plasma Focus Diode (SPFD, power densities of up to 4.3 kJ/cm2). Numerical results of accelerated flyer velocity agreed well with measured one over wide range of incident ion beam energy density. Flyer velocity of 5.6 km/s and ablation plasma pressure of 15 GPa was demonstrated by the present experiments. Acceleration of double-layer target consists of gold/aluminum was studied. For adequate layer thickness, such a flyer target could be much more accelerated than a single layer. Effect of waveform of ion beam was also examined. Parabolic waveform could accelerate more efficiently than rectangular waveform. Applicability of ablation propulsion was discussed. Specific impulse of 7000{approx}8000 seconds and time averaged thrust of up to 5000{approx}6000N can be expected. Their values can be controllable by changing power density of incident ion beam and pulse duration.
Harada, Nobuhiro; Buttapeng, Chainarong; Yazawa, Masaru [Department of Electrical Engineering, Nagaoka University of Technology, 1603 Kamitomioka, Nagaoka 940-2188 (Japan); Kashine, Kenji [Department of Electrical and Electronic Engineering, Kagoshima National College of Technology, 1460-1 Shinko, Hayato-cho, Aira-gun, Kagoshima 899-5193 (Japan); Jiang Weihua; Yatsui, Kiyoshi [Extreme Energy Density Research Institute, Nagaoka University of Technology, 1603 Kamitomioka, Nagaoka 940-2188 (Japan)
Reliability of Beam Loss Monitor Systems for the Large Hadron Collider
Science Journals Connector (OSTI)
The increase of beam energy and beam intensity together with the use of super conducting magnets opens new failure scenarios and brings new criticalities for the whole accelerator protection system. For the LHC beam loss protection system the failure rate and the availability requirements have been evaluated using the Safety Integrity Level (SIL) approach. A downtime cost evaluation is used as input for the SIL approach. The most critical systems which contribute to the final SIL value are the dump system the interlock system the beam loss monitors system and the energy monitor system. The Beam Loss Monitors System (BLMS) is critical for short and intense particles losses at 7 TeV and assisted by the Fast Beam Current Decay Monitors at 450 GeV. At medium and higher loss time it is assisted by other systems such as the quench protection system and the cryogenic system. For BLMS hardware and software have been evaluated in detail. The reliability input figures have been collected using historical data from the SPS using temperature and radiation damage experimental data as well as using standard databases. All the data has been processed by reliability software (Isograph). The analysis spaces from the components data to the system configuration.
G. Guaglio; B. Dehning; C. Santoni
Female Team Overall Name Age Rank Time Rank Time Rank Time Pace Rank Time Rank Time Pace Time
Female Team Overall Name Age Rank Time Rank Time Rank Time Pace Rank Time Rank Time Pace Time 1 Amy:56:27.6 Deborah Mc Eligot Deborah Storrings Male Team Overall Name Age Rank Time Rank Time Rank Time Pace Rank Time Rank Time Pace Time 1 Macon Fessenden 20 1 5:42.2 2 0:26.9 1 34:29.7 3:23 1 0:12.8 1 17:41.1 3
Suzuki, Masatsugu
Sensor Beams, Obstacles, and Possible Paths Benjamin Tovar1
Sensor Beams, Obstacles, and Possible Paths Benjamin Tovar1 , Fred Cohen2 , and Steven M. LaValle1, or animal) travels among obstacles and binary detection beams. The task is to determine the possible agent settings, which may arise from physical sensor beams or virtual beams that are derived from other sensing
LaValle, Steven M.
FOCUSED GAUSSIAN BEAMS FOR SEISMIC IMAGING ROBERT L. NOWACK Abstract. The application of focused Gaussian beams is investigated for the seismic imaging of common-shot reflection data. The focusing of Gaussian beams away from the source and receiver surface adds flexibility to beam imaging algorithms
Nowack, Robert L.
Title of Dissertation: CONTROL AND TRANSPORT OF INTENSE ELECTRON BEAMS
ABSTRACT Title of Dissertation: CONTROL AND TRANSPORT OF INTENSE ELECTRON BEAMS Hui Li, Doctor Engineering The transport of intense beams for advanced accelerator applications with high-intensity beams of beam characteristics over long distances. The University of Maryland Electron Ring (UMER), which uses
Anlage, Steven
plasma focusing and plasma accel- eration, but further beam compression is not required. The resulting
Wurtele, Jonathan
ECR plasma source for heavy ion beam charge neutralization
resonance. Keywords: Plasma focus; RF plasma; Beam charge neutralization 1. INTRODUCTION A possible heavy
Gilson, Erik
Dynamic cone beam CT angiography of carotid and cerebral arteries using canine model
Purpose: This research is designed to develop and evaluate a flat-panel detector-based dynamic cone beam CT system for dynamic angiography imaging, which is able to provide both dynamic functional information and dynamic anatomic information from one multirevolution cone beam CT scan. Methods: A dynamic cone beam CT scan acquired projections over four revolutions within a time window of 40 s after contrast agent injection through a femoral vein to cover the entire wash-in and wash-out phases. A dynamic cone beam CT reconstruction algorithm was utilized and a novel recovery method was developed to correct the time-enhancement curve of contrast flow. From the same data set, both projection-based subtraction and reconstruction-based subtraction approaches were utilized and compared to remove the background tissues and visualize the 3D vascular structure to provide the dynamic anatomic information. Results: Through computer simulations, the new recovery algorithm for dynamic time-enhancement curves was optimized and showed excellent accuracy to recover the actual contrast flow. Canine model experiments also indicated that the recovered time-enhancement curves from dynamic cone beam CT imaging agreed well with that of an IV-digital subtraction angiography (DSA) study. The dynamic vascular structures reconstructed using both projection-based subtraction and reconstruction-based subtraction were almost identical as the differences between them were comparable to the background noise level. At the enhancement peak, all the major carotid and cerebral arteries and the Circle of Willis could be clearly observed. Conclusions: The proposed dynamic cone beam CT approach can accurately recover the actual contrast flow, and dynamic anatomic imaging can be obtained with high isotropic 3D resolution. This approach is promising for diagnosis and treatment planning of vascular diseases and strokes.
Cai Weixing; Zhao Binghui; Conover, David; Liu Jiangkun; Ning Ruola [Department of Imaging Sciences, University of Rochester, 601 Elmwood Avenue, Rochester, New York 14642 (United States); Department of Radiology, Shanghai 6th People's Hospital, 600 Yishan Road, Xuhui, Shanghai (China); Koning Corporation, Lennox Tech Enterprise Center, 150 Lucius Gordon Drive Suite 112, West Henrietta, New York 14586 (United States); Department of Imaging Sciences, University of Rochester, 601 Elmwood Avenue, Rochester, New York 14642 (United States); Department of Imaging Sciences, University of Rochester, 601 Elmwood Avenue, Rochester, New York 14642 (United States) and Koning Corporation, Lennox Tech Enterprise Center, 150 Lucius Gordon Drive Suite 112, West Henrietta, New York 14586 (United States)
Positron Beam Propagation in a Meter Long Plasma Channel
Recent experiments and simulations have shown that positron beams propagating in plasmas can be focused and also create wakes with large accelerating gradients. For similar parameters, the wakes driven by positron beams are somewhat smaller compared to the case of an electron beam. Simulations have shown that the wake amplitude can be increased if the positron beam is propagated in a hollow plasma channel (Ref. 1). This paper, compares experimentally, the propagation and beam dynamics of a positron beam in a meter scale homogeneous plasma, to a positron beam hollow channel plasma. The results show that positron beams in hollow channels are less prone to distortions and deflections. Hollow channels were observed to guide the positron beam onto the channel axis. Beam energy loss was also observed implying the formation of a large wake amplitude. The experiments were carried out as part of the E-162 plasma wakefield experiments at SLAC.
Marsh, K.A.; Blue, B.E.; Clayton, C.E.; Joshi, C.; Mori, W.B.; /UCLA; Decker, F.-J.; Hogan, M.J.; Iverson, R.; O'Connell, C.; Raimondi, P.; Siemann, Robert H.; Walz, D.; /SLAC; Katsouleas, T.C.; Muggli, P.; /Southern California U.
On Gaussian Beams Described by Jacobi's Equation
Gaussian beams describe the amplitude and phase of rays and are widely used to model acoustic propagation. This paper describes four new results in the theory of Gaussian beams. (1) A new version of the \\v{C}erven\\'y equations for the amplitude and phase of Gaussian beams is developed by applying the equivalence of Hamilton-Jacobi theory with Jacobi's equation that connects Riemannian curvature to geodesic flow. Thus the paper makes a fundamental connection between Gaussian beams and an acoustic channel's so-called intrinsic Gaussian curvature from differential geometry. (2) A new formula $\\pi(c/c")^{1/2}$ for the distance between convergence zones is derived and applied to several well-known profiles. (3) A class of "model spaces" are introduced that connect the acoustics of ducting/divergence zones with the channel's Gaussian curvature $K=cc"-(c')^2$. The "model" SSPs yield constant Gaussian curvature in which the geometry of ducts corresponds to great circles on a sphere and convergence zones correspond to antipodes. The distance between caustics $\\pi(c/c")^{1/2}$ is equated with an ideal hyperbolic cosine SSP duct. (4) An "intrinsic" version of \\v{C}erven\\'y's formulae for the amplitude and phase of Gaussian beams is derived that does not depend on an "extrinsic" arbitrary choice of coordinates such as range and depth. Direct comparisons are made between the computational frameworks used by the three different approaches to Gaussian beams: Snell's law, the extrinsic Frenet-Serret formulae, and the intrinsic Jacobi methods presented here. The relationship of Gaussian beams to Riemannian curvature is explained with an overview of the modern covariant geometric methods that provide a general framework for application to other special cases.
Steven Thomas Smith
Variation of Langmuir wave polarization with electron beam speed in type III radio bursts
Observations by the twin STEREO spacecraft of in-situ electric field waveforms and radio signatures associated with type III radio bursts have demonstrated that the polarization of electron beam-driven waves near the local plasma frequency depends strongly on the speed of the driving electron beam. We expand upon a previous study by including all radio bursts with in-situ waveforms observed by STEREO in 2011. The expanded data set contains five times more radio bursts (35 up from 7) and three times as many Langmuir waves (663 up from 168). While this expanded study supports the results of the original study, that faster (slower) beam electrons drive waves with strong (weak) electric fields perpendicular to the local magnetic field, the larger data set emphasizes that the observation of strong perpendicular electric fields at high electron beam speeds is probabilistic rather than definite. This property supports the interpretation of wave polarization dependence on beam speed as Langmuir/z-mode waves shifted to small wave number through interaction with turbulent solar wind density fluctuations.
Malaspina, David M. [Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80303 (United States); Cairns, Iver H. [School of Physics, University of Sydney, New South Wales 2006 (Australia); Ergun, Robert E. [Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80303 (United States) and Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO 80303 (United States)
Laser power beaming to extend lives of GSO NiCd satellites
It is proposed that a ground-based laser can beam power to commercial communication satellites in geosynchronous orbit and reduce battery depth-of-discharge during eclipses. Two laser system designs are presented which have the capability of reducing battery discharge by 100%. Both utilize a steerable beam director, with a mirror diameter of 4 meters in one case and 8 meters in the other. Both also use an adaptive optics unit within the beam train to provide real-time corrections for wavefront distortions caused by atmospheric turbulence. The required system power output is in the range of 100 to 200 kW for a transmitted wavelength just under 900 nm. Laser power beaming can nearly double the remaining lifetime of a satellite that uses NiCd batteries. However, by the time such lasers become available, nearly all NiCd satellites will be replaced by NiH{sub 2} satellites, which stand to benefit much less from power beaming.
Monroe, D.K.
Low-intensity beam diagnostics with particle detectors
The measure of low intensity beams at low-medium energy is one of the major challenge in beam diagnostics. This subject is of great interest for the design of accelerator-based medical and radioactive beam facilities. In this paper we discuss new developments in image-based devices to measure low-intensity beams. All the investigated devices must guarantee measurement of the total beam current and its transverse distribution. {copyright} {ital 1997 American Institute of Physics.}
Rovelli, A.; Ciavola, G.; Cuttone, G.; Finocchiaro, P.; Raia, G. [INFN-LNS, Via S. Sofia 44/A Catania, 95125 (Italy); De Martinis, C.; Giove, D. [INFN-LASA, Via F.lli Cervi 201 Segrate (Midway Islands), 20090 (Italy)
Polarization of fast particle beams by collisional pumping
The invention relates to method and apparatus for polarizing a fast beam of particles by collisional pumping, including generating a fast beam of particles, and generating a thick electron-spin-polarized medium positioned as a target for said beam, said medium being sufficiently thick to allow said beam to interact with said medium to produce collisional pumping whereby said particle beam becomes highly polarized.
Stearns, J.W.; Kaplan, S.N.; Pyle, R.V.; Anderson, L.W.; Schlachter, A.S.; Ruby, L.
BeamDyn: A High-Fidelity Wind Turbine Blade Solver in the FAST Modular Framework: Preprint
BeamDyn, a Legendre-spectral-finite-element implementation of geometrically exact beam theory (GEBT), was developed to meet the design challenges associated with highly flexible composite wind turbine blades. In this paper, the governing equations of GEBT are reformulated into a nonlinear state-space form to support its coupling within the modular framework of the FAST wind turbine computer-aided engineering (CAE) tool. Different time integration schemes (implicit and explicit) were implemented and examined for wind turbine analysis. Numerical examples are presented to demonstrate the capability of this new beam solver. An example analysis of a realistic wind turbine blade, the CX-100, is also presented as validation.
Wang, Q.; Sprague, M.; Jonkman, J.; Johnson, N.
H{sup -} beam transport experiments in a solenoid low energy beam transport
The Front End Test Stand (FETS) is located at Rutherford Appleton Laboratory and aims for a high current, fast chopped 3 MeV H{sup -} ion beam suitable for future high power proton accelerators like ISIS upgrade. The main components of the front end are the Penning ion source, a low energy beam transport line, an radio-frequency quadrupole (RFQ) and a medium energy beam transport (MEBT) providing also a chopper section and rebuncher. FETS is in the stage of commissioning its low energy beam transport (LEBT) line consisting of three solenoids. The LEBT has to transport an H{sup -} high current beam (up to 60 mA) at 65 keV. This is the injection energy of the beam into the RFQ. The main diagnostics are slit-slit emittance scanners for each transversal plane. For optimizing the matching to the RFQ, experiments have been performed with a variety of solenoid settings to better understand the actual beam transport. Occasionally, source parameters such as extractor slit width and beam energy were varied as well. The paper also discusses simulations based on these measurements.
Gabor, C. [ASTeC Intense Beams Group, Rutherford Appleton Laboratory, Chilton, Didcot - Oxfordshire OX11 0QX (United Kingdom); Back, J. J. [High Energy Physics Department, University of Warwick, Coventry CV4 7AL (United Kingdom); Faircloth, D. C.; Lawrie, S. R.; Letchford, A. P. [ISIS Pulsed Spallation Neutron Source, Rutherford Appleton Laboratory, Chilton, Didcot - Oxfordshire OX11 0QX (United Kingdom); Izaola, Z. [ESS Bilbao, Accelerator Physics Group, Edificio Cosimet Paseo Landabarri, 2, 1 Planta. 48940 Leioa (Spain)
Indirectly sensing accelerator beam currents for limiting maximum beam current magnitude
A beam current limiter is disclosed for sensing and limiting the beam current in a particle accelerator, such as a cyclotron or linear accelerator, used in scientific research and medical treatment. A pair of independently operable capacitive electrodes sense the passage of charged particle bunches to develop an RF signal indicative of the beam current magnitude produced at the output of a bunched beam accelerator. The RF signal produced by each sensing electrode is converted to a variable DC voltage indicative of the beam current magnitude. The variable DC voltages thus developed are compared to each other to verify proper system function and are further compared to known references to detect beam currents in excess of pre-established limits. In the event of a system malfunction, or if the detected beam current exceeds pre-established limits, the beam current limiter automatically inhibits further accelerator operation. A high Q tank circuit associated with each sensing electrode provides a narrow system bandwidth to reduce noise and enhance dynamic range. System linearity is provided by injecting, into each sensing electrode, an RF signal that is offset from the bunching frequency by a pre-determined beat frequency to ensure that subsequent rectifying diodes operate in a linear response region. The system thus provides a large dynamic range in combination with good linearity. 6 figs.
Bogaty, J.M.; Clifft, B.E.; Bollinger, L.M.
The Program in Muon and Neutrino Physics: Super Beams, Cold Muon Beams,
The Program in Muon and Neutrino Physics: Super Beams, Cold Muon Beams, Neutrino Factory and the Muon Collider Editor: Rajendran Raja1 1 Fermi National Accelerator Laboratory, Batavia, IL 60510, USA Members of the Executive Board of the Muon Collaboration D. Cline,2 J. Gallardo,3 S. Geer,1 D. Kaplan,4 K
Eric Feng, HEP Lunch Seminar A Beam-Beam Trigger for ATLAS with
Eric Feng, HEP Lunch Seminar 4/23/07 1 A Beam-Beam Trigger for ATLAS with MinBias Trigger) · Trigger the ATLAS detector during early low-luminosity running, especially commissioning run at 900 Ge/23/07 6 Scope Trace of Signal from Trigger Cable Low gain: · Differential signal, single shot (left
Beam-beam interaction and pacman effects in the SSC with random nonlinear multipoles
In order to find the combined effects of beam-beam interaction (head-on and long-range) and random nonlinear multipoles in dipole magnets, transverse tunes and smears have been calculated as a function of oscillation amplitudes. Two types of particles, ''regular'' and ''pacman,'' have been investigated using a modified version of the tracking code TEAPOT. Regular particles experience beam-beam interactions in all four interaction regions (IR's), both head-on and long-range, while pacman particles interact with bunches of the other beam in one medium-beta and one low-beta IR's only. The model for the beam-beam interaction is of weak-strong type and the strong beam is assumed to have a round Gaussian charge distribution. Furthermore, it is assumed that the vertical closed orbit deviation arising from the finite crossing angle of 70 ..mu..rad is perfectly compensated for regular particles. The same compensation applied to pacman particles creates a closed orbit distortion. Linear tunes are adjusted for regular particles to the design values but there are no nonlinear corrections except for chromaticity correcting sextupoles in two families. Results obtained in this study do not show any reduction of dynamic or linear apertures for pacman particles when the oscillation amplitude is less than /approximately/10sigma. However, smears often exhibit a strong dependence on tunes, casting some doubts on the validity of defining the linear aperture from the smear alone. 10 refs., 16 figs., 3 tabs.
Goderre, G.P.; Mahale, N.K.; Ohnuma, S.
Method for measuring and controlling beam current in ion beam processing
A method for producing film thickness control of ion beam sputter deposition films. Great improvements in film thickness control is accomplished by keeping the total current supplied to both the beam and suppressor grids of a radio frequency (RF) in beam source constant, rather than just the current supplied to the beam grid. By controlling both currents, using this method, deposition rates are more stable, and this allows the deposition of layers with extremely well controlled thicknesses to about 0.1%. The method is carried out by calculating deposition rates based on the total of the suppressor and beam currents and maintaining the total current constant by adjusting RF power which gives more consistent values.
Kearney, Patrick A. (Livermore, CA); Burkhart, Scott C. (Livermore, CA)
Beam diagnostics measurements at 3 MeV of the LINAC4 H- beam at CERN
As part of the CERN LHC injector chain upgrade, LINAC4 [1, 2] will accelerate H- ions to 160 MeV, replacing the old 50 MeV proton linac. The ion source, the Low Energy Beam Transfer (LEBT) line, the 3 MeV Radio Frequency Quadrupole and the Medium Energy Beam Transfer (MEBT) line hosting a chopper, have been commissioned in the LINAC4 tunnel. Diagnostic devices are installed in the LEBT and MEBT line and in a movable diagnostics test bench which is temporarily added to the MEBT exit. The paper gives an overview of all the instruments used, including beam current transformers, beam position monitors, wire scanners and wire grids for transverse profile measurements, a longitudinal bunch shape monitor and a slit-and-grid emittance meter. The instrumentation performance is discussed and the measurement results that allowed characterizing the 3 MeV beam in the LINAC4 tunnel are summarized.
Zocca, F; Duraffourg, M; Focker, G J; Gerard, D; Kolad, B; Lenardon, F; Ludwig, M; Raich, U; Roncarolo, F; Sordet, M; Tan, J; Tassan-Viol, J; Vuitton, C; Feshenko, A
High power linear pulsed beam annealer
A high power pulsed electron beam is produced in a system comprised of an electron gun having a heated cathode, control grid, focus ring, and a curved drift tube. The drift tube is maintained at a high positive voltage with respect to the cathode to accelerate electrons passing through the focus ring and to thereby eliminate space charge. A coil surrounding the curved drift tube provides a magnetic field which maintains the electron beam focused about the axis of the tube and imparts motion on electrons in a spiral path for shallow penetration of the electrons into a target. The curvature of the tube is selected so there is no line of sight between the cathode and a target holder positioned within a second drift tube spaced coaxially from the curved tube. The second tube and the target holder are maintained at a reference voltage that decelerates the electrons. A second coil surrounding the second drift tube maintains the electron beam focused about the axis of the second drift tube and compresses the electron beam to the area of the target. The target holder can be adjusted to position the target where the cross section of the beam matches the area of the target.
Strathman, Michael D. (Concord, CA); Sadana, Devendra K. (Berkeley, CA); True, Richard B. (Sunnyvale, CA)
Holographic generation of highly twisted electron beams
Free electrons can possess an intrinsic orbital angular momentum, similar to those in an electron cloud, upon free-space propagation. The wavefront corresponding to the electron's wavefunction forms a helical structure with a number of twists given by the \\emph{angular speed}. Beams with a high number of twists are of particular interest because they carry a high magnetic moment about the propagation axis. Among several different techniques, electron holography seems to be a promising approach to shape a \\emph{conventional} electron beam into a helical form with large values of angular momentum. Here, we propose and manufacture a nano-fabricated phase hologram for generating a beam of this kind with an orbital angular momentum up to 200$\\hbar$. Based on a novel technique the value of orbital angular momentum of the generated beam are measured, then compared with simulations. Our work, apart from the technological achievements, may lead to a way of generating electron beams with a high quanta of magnetic momen...
Grillo, Vincenzo; Mafakheri, Erfan; Frabboni, Stefano; Karimi, Ebrahim; Boyd, Robert W
The Particle Beam Optics Interactive Computer Laboratory
The Particle Beam Optics Interactive Computer Laboratory (PBO Lab) is an educational software concept to aid students and professionals in learning about charged particle beams and particle beam optical systems. The PBO Lab is being developed as a cross-platform application and includes four key elements. The first is a graphic user interface shell that provides for a highly interactive learning session. The second is a knowledge database containing information on electric and magnetic optics transport elements. The knowledge database provides interactive tutorials on the fundamental physics of charged particle optics and on the technology used in particle optics hardware. The third element is a graphical construction kit that provides tools for students to interactively and visually construct optical beamlines. The final element is a set of charged particle optics computational engines that compute trajectories, transport beam envelopes, fit parameters to optical constraints and carry out similar calculations for the student designed beamlines. The primary computational engine is provided by the third-order TRANSPORT code. Augmenting TRANSPORT is the multiple ray tracing program TURTLE and a first-order matrix program that includes a space charge model and support for calculating single particle trajectories in the presence of the beam space charge. This paper describes progress on the development of the PBO Lab.
Gillespie, George H.; Hill, Barrey W.; Brown, Nathan A.; Babcock, R. Chris; Martono, Hendy; Carey, David C. [G. H. Gillespie Associates, Inc., P.O. Box 2961, Del Mar, California 92014, United States of America (United States); G. H. Gillespie Associates, Inc., P.O. Box 2961, Del Mar, California 92014, United States of America (United States); Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, Illinois 60510 (United States)
The Particle Beam Optics Interactive Computer Laboratory
The Particle Beam Optics Interactive Computer Laboratory (PBO Lab) is an educational software concept to aid students and professionals in learning about charged particle beams and particle beam optical systems. The PBO Lab is being developed as a cross-platform application and includes four key elements. The first is a graphic user interface shell that provides for a highly interactive learning session. The second is a knowledge database containing information on electric and magnetic optics transport elements. The knowledge database provides interactive tutorials on the fundamental physics of charged particle optics and on the technology used in particle optics hardware. The third element is a graphical construction kit that provides tools for students to interactively and visually construct optical beamlines. The final element is a set of charged particle optics computational engines that compute trajectories, transport beam envelopes, fit parameters to optical constraints and carry out similar calculations for the student designed beamlines. The primary computational engine is provided by the third-order TRANSPORT code. Augmenting TRANSPORT is the multiple ray tracing program TURTLE and a first-order matrix program that includes a space charge model and support for calculating single particle trajectories in the presence of the beam space charge. This paper describes progress on the development of the PBO Lab. {copyright} {ital 1997 American Institute of Physics.}
Gillespie, G.H.; Hill, B.W.; Brown, N.A.; Babcock, R.C.; Martono, H. [G. H. Gillespie Associates, Inc., P.O. Box 2961, Del Mar, California 92014 (United States of America); Carey, D.C. [G. H. Gillespie Associates, Inc., P.O. Box 2961, Del Mar, California 92014 (United States of America)]|[Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, Illinois 60510 (United States)
A Resistive Wideband Space Beam Splitter
We present the design, construction and measurements of the electromagnetic performance of a wideband space beam splitter. The beam splitter is designed to power divide the incident radiation into reflected and transmitted components for interferometer measurement of spectral features in the mean cosmic radio background. Analysis of a 2-element interferometer configuration with a vertical beam splitter between a pair of antennas leads to the requirement that the beam splitter be a resistive sheet with sheet resistance {\\eta}o /2, where {\\eta}o is the impedance of free space. The transmission and reflection properties of such a sheet is computed for normal and oblique incidences and for orthogonal polarizations of the incident electric field. We have constructed such an electromagnetic beam splitter as a square soldered grid of resistors of value 180 Ohms (approximately {\\eta}o /2) and a grid size of 0.1 m, and present measurements of the reflection and transmission coefficients over a wide frequency range bet...
Mahesh, Nivedita; Shankar, N Udaya; Raghunathan, Agaram
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Perlmutter, et al., in Thermonuclear Supernovae, NATO ASI, v. 486 (1997) Perlmutter, et al., in Thermonuclear Supernovae, NATO ASI, v. 486 (1997) Cosmology from . . . Time Brightness ... . . . 50-100 Fields Lunar Calendar Scheduled Follow-Up Imaging at Hubble, Cerro Tololo, WIYN, Isaac Newton Scheduled Follow-Up Spectroscopy at Keck Almost 1000 Galaxies per Field RESULT: ~24 Type Ia supernovae discovered while still brightening, at new moon Berkeley Lab Keck WIYN Cerro Tololo Isaac Newton Hubble Strategy We developed a strategy to guarantee a group of supernova discoveries on a certain date. Just after a new moon, we observe some 50 to 100 high-galactic lattitute fields-each containing almost a thousand high-redshift galaxies-in two nights on the Cerro Tololo 4-meter telescope with Tyson & Bernstein's wide-field camera. We return three weeks later to observe the same
The authors have built monitors for use as beam diagnostics in the narrow gap of an undulator for an FEL experiment. They utilize an intercepting screen of doped YAG scintillating crystal to make light that is imaged through a periscope by conventional video equipment. The absolute position can be ascertained by comparing the electron beam position with the position of a He:Ne laser that is observed by this pop-in monitor. The optical properties of the periscope and the mechanical arrangement of the system mean that beam can be spatially determined to the resolution of the camera, in this case approximately 10 micrometers. The experience with these monitors suggests improvements for successor designs, which they also describe.
Johnson, E.D.; Graves, W.S. [Brookhaven National Lab., Upton, NY (United States). National Synchrotron Light Source; Robinson, K.E. [STI Optronics, Bellevue, WA (United States)
Princeton Plasma Physics Lab - Particle beam dynamics
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particle-beam-dynamics The study of particle-beam-dynamics The study of the physics of charged particle beams and the accelerators that produce them. This cross-disciplinary area intersects with fields such as plasma physics, high-energy density science, and ultra-fast lasers. en Premiere issue of "Quest" magazine details PPPL's strides toward fusion energy and advances in plasma science http://www.pppl.gov/news/2013/09/premiere-issue-quest-magazine-details-pppls-strides-toward-fusion-energy-and-advances-0
Two exercises about neutrino departure times at CERN
Two simple exercises are solved, which educators can use to awake interest of their students in subtleties of the CERN Neutrino beam to Grand Sasso (CNGS) experiment. The first one is about the statistical error of the average departure time of neutrinos from CERN. The second one about a hypothetical bias in the departure times.
Bernd A. Berg; Peter Hoeflich
Using an IIDC/DCAM camera for beam display and analysis
An IIDC/DCAM camera is used to the RHIC beams as they pass through a hydrogen jet. The data is transferred over a 1394 bus to a computer with a Linux operating system. A software process on that computer collects the individual frames and packages them into parameters within the RHIC control system's framework. This information is packaged to continuously update two primary types of clients: One type is responsible for near-real-time display of the images; useful in comfort displays, etc. The second is responsible for collecting data used in analysis of beam dynamics and properties like luminosity.
Olsen,R.H.; Gassner, D.; Hoff, L. T.
Solid-liquid composite structures: elastic beams with embedded liquid-filled parallel-channel networks
Deformation due to embedded fluidic networks is currently studied in the context of soft-actuators and soft-robotics. Expanding on this concept, beams can be designed so that the pressure in the channel-network is created directly from external forces acting on the beam, and thus can be viewed as passive solid-liquid composite structure. We obtain a continuous function relating the network geometry to the deformation. This enables design of networks creating arbitrary steady and time varying deformation-fields as well as to eliminate deformation created by external forces.
Yoav Matia; Amir Gat
Ultrafast spectroscopy of super high frequency mechanical modes of doubly clamped beams
We use ultrafast pump-probe spectroscopy to study the mechanical vibrations in the time domain of doubly clamped silicon nitride beams. Beams with two different clamping conditions are investigated. Finite element method calculations are performed to analyse the mode spectra of both structures. By calculating the strain integral on the surface of the resonators, we are able to reproduce the effect of the detection mechanism and identify all the measured modes. We show that our spectroscopy technique combined with our modelling tools allow the investigation of several different modes in the super high frequency range (3-30?GHz) and above, bringing more information about the vibration modes of nanomechanical resonators.
Ristow, Oliver; Merklein, Moritz; Grossmann, Martin; Hettich, Mike; Schubert, Martin; Bruchhausen, Axel; Scheer, Elke; Dekorsy, Thomas; Barretto, Elaine C. S., E-mail: firstname.lastname@example.com [Department of Physics and Center of Applied Photonics, University of Konstanz, D-78457 Konstanz (Germany)] [Department of Physics and Center of Applied Photonics, University of Konstanz, D-78457 Konstanz (Germany); Grebing, Jochen; Erbe, Artur [Helmholtz-Zentrum Dresden - Rossendorf, Institute of Ion-Beam Physics and Materials Research, D-01328 Dresden (Germany)] [Helmholtz-Zentrum Dresden - Rossendorf, Institute of Ion-Beam Physics and Materials Research, D-01328 Dresden (Germany); Mounier, Denis [IMMM, UMR-CNRS 6283, ENSIM, PRES UNAM, Universit� du Maine, 72085 Le Mans (France)] [IMMM, UMR-CNRS 6283, ENSIM, PRES UNAM, Universit� du Maine, 72085 Le Mans (France); Gusev, Vitalyi [LAUM, UMR-CNRS 6613, PRES UNAM, Universit� du Maine, 72085 Le Mans (France)] [LAUM, UMR-CNRS 6613, PRES UNAM, Universit� du Maine, 72085 Le Mans (France)
ORISE: University Radioactive Ion Beam Consortium
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UNIRIB UNIRIB Research Overview Physics Topics Equipment Development Education and Training People Publications Overview 2009 Bibliography 2008 Bibliography 2007 Bibliography 2006 Bibliography How to Work With Us Contact Us Oak Ridge Institute for Science Education University Radioactive Ion Beam Consortium The University Radioactive Ion Beam (UNIRIB) consortium is a division of the Oak Ridge Institute for Science and Education (ORISE) focused on cutting-edge nuclear physics research. UNIRIB is a collaborative partnership involving Oak Ridge National Laboratory (ORNL) and nine member universities that leverages national laboratory and university resources to effectively accomplish the U.S. Department of Energy's (DOE) strategic goals in the fundamental structure of nuclei.
Power beaming providing a space power infrastructure
This study, based on two levels of technology, applies the power beaming concept to four planned satellite constellations. The analysis shows that with currently available technology, power beaming can provide mass savings to constellations in orbits ranging from low earth orbit to geosynchronous orbit. Two constellations, space surveillance and tracking system and space based radar, can be supported with current technology. The other two constellations, space-based laser array and boost surveillance and tracking system, will require power and transmission system improvements before their breakeven specific mass is achieved. A doubling of SP-100 conversion efficiency from 10 to 20/% would meet or exceed breakeven for these constellations.
Bamberger, J.A.; Coomes, E.P.
ATA diagnostic beam dump conceptual design
A diagnostic beam dump, able to withstand 72,000 pulses (10 kA, 50 MeV/pulse) per shift was designed and analyzed. The analysis shows that the conceptual beam dump design consisting of 80 vitreous carbon plate-foam elements is able to withstand the thermal and mechanical stresses generated. X-rays produced by bremsstrahlung are absorbed by a three element copper plate-foam x-ray absorber. Cooling between bursts of electron pulses is provided by pressurized helium.
Not Available
Polarized electron beams at milliampere average current
This contribution describes some of the challenges associated with developing a polarized electron source capable of uninterrupted days-long operation at milliAmpere average beam current with polarization greater than 80%. Challenges will be presented in the context of assessing the required level of extrapolation beyond the performance of today's CEBAF polarized source operating at ~ 200 uA average current. Estimates of performance at higher current will be based on hours-long demonstrations at 1 and 4 mA. Particular attention will be paid to beam-related lifetime-limiting mechanisms, and strategies to construct a photogun that operate reliably at bias voltage > 350kV.
Poelker, Matthew [JLAB
We report observations of type III radio bursts at decimeter wavelengths (type IIIdm bursts)-signatures of suprathermal electron beams propagating in the low corona-using the new technique of radio dynamic imaging spectroscopy provided by the recently upgraded Karl G. Jansky Very Large Array. For the first time, type IIIdm bursts were imaged with high time and frequency resolution over a broad frequency band, allowing electron beam trajectories in the corona to be deduced. Together with simultaneous hard X-ray and extreme ultraviolet observations, we show that these beams emanate from an energy release site located in the low corona at a height below {approx}15 Mm, and propagate along a bundle of discrete magnetic loops upward into the corona. Our observations enable direct measurements of the plasma density along the magnetic loops, and allow us to constrain the diameter of these loops to be less than 100 km. These overdense and ultra-thin loops reveal the fundamentally fibrous structure of the Sun's corona. The impulsive nature of the electron beams, their accessibility to different magnetic field lines, and the detailed structure of the magnetic release site revealed by the radio observations indicate that the localized energy release is highly fragmentary in time and space, supporting a bursty reconnection model that involves secondary magnetic structures for magnetic energy release and particle acceleration.
Chen Bin [Department of Astronomy, University of Virginia, Charlottesville, VA 22904 (United States); Bastian, T. S. [National Radio Astronomy Observatory, Charlottesville, VA 22903 (United States); White, S. M. [Air Force Research Laboratory, Kirtland Air Force Base, New Mexico, NM (United States); Gary, D. E. [Center for Solar-Terrestrial Research, New Jersey Institute of Technology, Newark, NJ 07102 (United States); Perley, R.; Rupen, M. [National Radio Astronomy Observatory, Socorro, NM 87801 (United States); Carlson, B. [National Research Council of Canada, Penticton, BC V2A 6J9 (Canada)
Compact two-beam push-pull free electron laser
An ultra-compact free electron laser comprising a pair of opposed superconducting cavities that produce identical electron beams moving in opposite directions such that each set of superconducting cavities accelerates one electron beam and decelerates the other electron beam. Such an arrangement, allows the energy used to accelerate one beam to be recovered and used again to accelerate the second beam, thus, each electron beam is decelerated by a different structure than that which accelerated it so that energy exchange rather than recovery is achieved resulting in a more compact and highly efficient apparatus.
Hutton, Andrew (Yorktown, VA)
Recent improvements to the DIII-D neutral beam instrumentation and control system
The DIII-D neutral beam (NB) instrumentation and control (I and C) system provides for operational control and synchronization of the eight DIII-D neutral beam injection systems, as well as for pertinent data acquisition and safety interlocking. Recently, improvements were made to the I and C system. With the replacement of the NB control computers, new signal interfacing was required to accommodate the elimination of physical operator panels, in favor of graphical user interface control pages on computer terminal screens. The program in the mode control (MC) programmable logic controller (PLC), which serves as a logic-processing interface between the NB control computers and system hardware, was modified to improve the availability of NB heating of DIII-D plasmas in the event that one or more individual beam systems suddenly become unavailable while preparing for a tokamak experimental shot sequences. An upgraded computer platform was adopted for the NB control system operator interface and new graphical user interface pages were developed to more efficiently display system status data. A failure mode of the armor tile infrared thermometers (pyrometers), which serve to terminate beam pulsing if beam shine-through overheats wall thermal shielding inside the DIII-D tokamak, was characterized such that impending failures can be detected and repairs effected to mitigate beam system down-time. The hardware that controls gas flow to the beamline neutralizer cells was upgraded to reduce susceptibility to electromagnetic interference (EMI), and interlocking was provided to terminate beam pulsing in the event of insufficient neutralizer gas flow. Motivation, implementation, and results of these improvements are presented.
Kellman, D.H.; Hong, R.
Long-Range And Head-On Beam-Beam Compensation Studies in RHIC With Lessons for the LHC
Long-range as well as head-on beam-beam effects are expected to limit the LHC performance with design parameters. They are are also important consideration for the LHC upgrades. To mitigate long-range effects, current carrying wires parallel to the beam were proposed. Two such wires are installed in RHIC where they allow studying the effect of strong long-range beam-beam effects, as well as the compensation of a single long-range interaction. The tests provide benchmark data for simulations and analytical treatments. Electron lenses were proposed for both RHIC and the LHC to reduce the head-on beam-beam effect. We present the experimental long-range beam-beam program at RHIC and report on head-on compensations studies based on simulations.
Fischer, W.; Luo, Y.; Abreu, N.; Calaga, R.; Montag, C.; Robert-Demolaize, G.; /Brookhaven; Dorda, U.; Koutchouk, J.P.; Sterbini, G.; Zimmermann, F.; /CERN; Kim, H.J.; Sen, T.; Shiltsev, V.; Valishev, A.; /Fermilab; Qiang, J.; /LBL, Berkeley; Kabel, A.; /SLAC
Further Analysis of Real Beam Line Optics From A Synthetic Beam
Standard closed-orbit techniques for Twiss parameter measurement are not applicable to the open-ended Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab. The evolution of selected sets of real orbits in the accelerator models the behavior of a 'synthetic' beam. This process will be validated against beam profile-based Twiss parameter measurements and should provide the distributed optical information needed to optimize beamline tuning for an open-ended system. This work will discuss the current and future states of this technique, as well as an example of its use in the CEBAF machine.
Ryan Bodenstein, Michael Tiefenback, Yves Roblin
Heavy ion beam loss mechanisms at an electron-ion collider
There are currently several proposals to build a high-luminosity electron-ion collider, to study the spin structure of matter and measure parton densities in heavy nuclei, and to search for gluon saturation and new phenomena like the colored glass condensate. These measurements require operation with heavy-nuclei. We calculate the cross-sections for two important processes that will affect accelerator and detector operations: bound-free pair production, and Coulomb excitation of the nuclei. Both of these reactions have large cross-sections, 28-56 mb, which can lead to beam ion losses, produce beams of particles with altered charge:mass ratio, and produce a large flux of neutrons in zero degree calorimeters. The loss of beam particles limits the sustainable electron-ion luminosity to levels of several times $10^{32}/$cm$^2$/s.
Spencer R. Klein
z-pinch plasma lens focusing of a heavy-ion beam
Science Journals Connector (OSTI)
For the first time a heavy-ion beam was focused using a z-pinch plasma lens. The diameter of an incident, parallel, 460-MeV argon-ion beam was reduced from ?8 mm (FWHM) to ?2 mm within 230 mm downstream of the plasma. Inside a cylindrically symmetric plasma column a high-gradient, azimuthal magnetic field is produced during a z-pinch discharge. For axially moving, high-energy charged particles this field configuration provides strong, first-order focusing simultaneously in both transversal planes. The measured spot size agrees with numerical calculations taking into account the finite beam emittance, and charge exchange as well as energy-loss processes contributing to aberrations.
E. Boggasch; J. Jacoby; H. Wahl; K.-G. Dietrich; D. H. H. Hoffmann; W. Laux; M. Elfers; C. R. Haas; V. P. Dubenkov; A. A. Golubev
Site-controlled fabrication of Ga nanodroplets by focused ion beam
Ga droplets are created by focused ion beam irradiation of GaAs surface. We report that ordered Ga droplets can be formed on the GaAs surface without any implantation damage. The droplets are characterized with bigger sizes than those droplets formed on damaged area. These aligned Ga droplets are formed via the migration of Ga atoms from ion irradiation area to the edge of undamaged GaAs surface and further nucleation into droplets. The morphological evolution and size distribution of these nanodroplets are investigated systematically with different beam irradiation time and incident angles. Based on this method, well positioned Ga nanodroplets, such as chains, are achieved by using focus ion beam patterning. The controllable assembly of droplets on undamaged semiconductor surface can be used to fabricate templates, to fabricate quantum structures and quantum devices by droplet epitaxy technique.
Xu, Xingliang; Wang, Zhiming M., E-mail: firstname.lastname@example.com [State Key Laboratory of Electronic Thin Film and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054 (China); Engineering Research Center for Semiconductor Integrated Technology, Institute of Semiconductors, Chinese Academy of Science, Beijing 100083 (China); Wu, Jiang; Li, Handong; Zhou, Zhihua [State Key Laboratory of Electronic Thin Film and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054 (China); Wang, Xiaodong [Engineering Research Center for Semiconductor Integrated Technology, Institute of Semiconductors, Chinese Academy of Science, Beijing 100083 (China)
Measurement of the Neutron Lifetime by Counting Trapped Protons in a Cold Neutron Beam
A measurement of the neutron lifetime $\\tau_{n}$ performed by the absolute counting of in-beam neutrons and their decay protons has been completed. Protons confined in a quasi-Penning trap were accelerated onto a silicon detector held at a high potential and counted with nearly unit efficiency. The neutrons were counted by a device with an efficiency inversely proportional to neutron velocity, which cancels the dwell time of the neutron beam in the trap. The result is $\\tau_{n} = (886.6\\pm1.2{\\rm [stat]}\\pm3.2{\\rm [sys]})$ s, which is the most precise measurement of the lifetime using an in-beam method. The systematic uncertainty is dominated by neutron counting, in particular the mass of the deposit and the $^{6}$Li({\\it{n,t}}) cross section. The measurement technique and apparatus, data analysis, and investigation of systematic uncertainties are discussed in detail.
J. S. Nico; M. S. Dewey; D. M. Gilliam; F. E. Wietfeldt; X. Fei; W. M. Snow; G. L. Greene; J. Pauwels; R. Eykens; A. Lamberty; J. Van Gestel; R. D. Scott
Reliability of Beam Loss Monitors System for the Large Hadron Collider
The employment of superconducting magnets, in the high energies colliders, opens challenging failure scenarios and brings new criticalities for the whole system protection. For the LHC beam loss protection system, the failure rate and the availability requirements have been evaluated using the Safety Integrity Level (SIL) approach. A downtime cost evaluation is used as input for the SIL approach. The most critical systems, which contribute to the final SIL value, are the dump system, the interlock system, the beam loss monitors system and the energy monitor system. The Beam Loss Monitors System (BLMS) is critical for short and intense particles losses, while at medium and higher loss time it is assisted by other systems, such as the quench protection system and the cryogenic system. For BLMS, hardware and software have been evaluated in detail. The reliability input figures have been collected using historical data from the SPS, using temperature and radiation damage experimental data as well as using standar...
Guaglio, Gianluca; Santoni, C
Final Report for Sheet Beam Klystron Program
The Phase I program demonstrated feasibility of the RF circuit, periodic permanent magnet focusing and beam transport. Computer simulations indicate that the device should meet the goals of the program with the anticipated power and efficiency. The electron gun is currently under construction in another program, and the collector is a simple design based on existing technology.
Michael Read; Lawrence Ives; Purobi Phillips
Focused ion beam micromilling and articles therefrom
An ultrahigh vacuum focused ion beam micromilling apparatus and process are isclosed. Additionally, a durable data storage medium using the micromilling process is disclosed, the durable data storage medium capable of storing, e.g., digital or alphanumeric characters as well as graphical shapes or characters.
Lamartine, Bruce C. (Los Alamos, NM); Stutz, Roger A. (Los Alamos, NM)
Focused ion beam micromilling and articles therefrom
An ultrahigh vacuum focused ion beam micromilling apparatus and process are disclosed. Additionally, a durable data storage medium using the micromilling process is disclosed, the durable data storage medium capable of storing, e.g., digital or alphanumeric characters as well as graphical shapes or characters. 6 figs.
Lamartine, B.C.; Stutz, R.A.
Beam Test Possibilities in Japan Tatsushi NAKAMOTO
Beam Test Possibilities in Japan Tatsushi NAKAMOTO KEK Feb. 15, 2012 1 Radiation Effects Evaluation apparatuses #12;Overview of Facilities in Japan Feb. 15, 2012 Radiation Effects Materials (RESMM'12) 8 #12;Overview of Facilities in Japan Feb. 15, 2012 Radiation Effects
McDonald, Kirk
Beam current controller for laser ion source
The present invention relates to the design and use of an ion source with a rapid beam current controller for experimental and medicinal purposes. More particularly, the present invention relates to the design and use of a laser ion source with a magnetic field applied to confine a plasma flux caused by laser ablation.
Okamura, Masahiro
Commissioning the polarized beam in the AGS
After the successful operation of a high energy polarized proton beam at the Argonne Laboratory Zero Gradient Synchrotron (ZGS) was terminated, plans were made to commission such a beam at the Brookhaven National Laboratory Alternating Gradient Synchrotron (AGS). On February 23, 1984, 2 ..mu..A of polarized H/sup -/ was accelerated through the Linac to 200 MeV with a polarization of about 65%. 1 ..mu..A was injected into the AGS and acceleration attempts began. Several relatively short runs were then made during the next three months. Dedicated commissioning began in early June, and on June 26 the AGS polarized beam reached 13.8 GeV/c to exceed the previous ZGS peak momentum of 12.75 GeV/c. Commissioning continued to the point where 10/sup 10/ polarized protons were accelerated to 16.5 GeV/c with 40% polarization. Then, two experiments had a short polarized proton run. We plan to continue commissioning efforts in the fall of this year to reach higher energy, higher intensity, and higher polarization levels. We present a brief description of the facility and of the methods used for preserving the polarization of the accelerating beam.
Ratner, L.G.; Brown, H.; Chiang, I.H.; Courant, E.; Gardner, C.; Lazarus, D.; Lee, Y.Y.; Makdisi, Y.; Sidhu, S.; Skelly, J.
Beam-Foil Spectroscopy - Quo Vadis?
Beam-foil spectroscopy after 45 years: what has been realized of the promises, what is the state of the art, what is the status of the field, what present atomic physics problems should the technique be applied to, where can it be done? Will it be done? Beam-foil spectroscopy and its sibling techniques have been outstandingly productive tools of atomic physics, providing both important data and insight. For some forty years, the developments have led to improvements in working range and reliability, and catalogues of desirable further measurements can be formulated. However, most of the key persons who have carried out and directed much of the development effort are nearing retirement, and with them the leading facilities. it is thus not likely that many of the desirable BFS projects discussed will presently be pursued. High-Z element, high-charge state spectroscopy and some specific long-lived level lifetime measurements will, however, be taken over by electron beam ion traps, and heavy-ion storage rings will contribute some important benchmark measurements on electric-dipole forbidden or hyperfine-induced transitions. Beam-foil spectroscopy can still be expected to solve a number of interesting atomic physics questions, but as a technique, at present, it has dropped from fashion and support.
Trabert, E
Inertial Confinement Fusion with Light Ion Beams
Science Journals Connector (OSTI)
...plasma can be formed without significant contribution of the ion thermal velocity to the beam divergence. The large ionization energy...3. P. L. Dreike, C. Eichenberger, S. Humphries, R. Sudan, J. Appi. Phys. 47, 85 (1986). 4. J. D. Lindi and...
Trirotron: triode rotating beam radio frequency amplifier
High efficiency amplification of radio frequencies to very high power levels including: establishing a cylindrical cloud of electrons; establishing an electrical field surrounding and coaxial with the electron cloud to bias the electrons to remain in the cloud; establishing a rotating electrical field that surrounds and is coaxial with the steady field, the circular path of the rotating field being one wavelength long, whereby the peak of one phase of the rotating field is used to accelerate electrons in a beam through the bias field in synchronism with the peak of the rotating field so that there is a beam of electrons continuously extracted from the cloud and rotating with the peak; establishing a steady electrical field that surrounds and is coaxial with the rotating field for high-energy radial acceleration of the rotating beam of electrons; and resonating the rotating beam of electrons within a space surrounding the second field, the space being selected to have a phase velocity equal to that of the rotating field to thereby produce a high-power output at the frequency of the rotating field.
Lebacqz, Jean V. (Stanford, CA)
Axial and transverse acoustic radiation forces on a fluid sphere placed arbitrarily in Bessel beam standing wave tweezers
The axial and transverse radiation forces on a fluid sphere placed arbitrarily in the acoustical field of Bessel beams of standing waves are evaluated. The three-dimensional components of the time-averaged force are expressed in terms of the beam-shape coefficients of the incident field and the scattering coefficients of the fluid sphere using a partial-wave expansion (PWE) method. Examples are chosen for which the standing wave field is composed of either a zero-order (non-vortex) Bessel beam, or a first-order Bessel vortex beam. It is shown here, that both transverse and axial forces can push or pull the fluid sphere to an equilibrium position depending on the chosen size parameter ka (where k is the wave-number and a the sphere�s radius). The corresponding results are of particular importance in biophysical applications for the design of lab-on-chip devices operating with Bessel beams standing wave tweezers. Moreover, potential investigations in acoustic levitation and related applications in particle rotation in a vortex beam may benefit from the results of this study. -- Highlights: �The axial and transverse forces on a fluid sphere in acoustical Bessel beams tweezers are evaluated. �The attraction or repulsion to an equilibrium position in the standing wave field is examined. �Potential applications are in particle manipulation using standing waves.
Mitri, F.G., E-mail: email@example.com
Ion source and beam guiding studies for an API neutron generator
Recently developed neutron imaging methods require high neutron yields for fast imaging times and small beam widths for good imaging resolution. For ion sources with low current density to be viable for these types of imaging methods, large extraction apertures and beam focusing must be used. We present recent work on the optimization of a Penning-type ion source for neutron generator applications. Two multi-cusp magnet configurations have been tested and are shown to increase the extracted ion current density over operation without multi-cusp magnetic fields. The use of multi-cusp magnetic confinement and gold electrode surfaces have resulted in increased ion current density, up to 2.2 mA/cm{sup 2}. Passive beam focusing using tapered dielectric capillaries has been explored due to its potential for beam compression without the cost and complexity issues associated with active focusing elements. Initial results from first experiments indicate the possibility of beam compression. Further work is required to evaluate the viability of such focusing methods for associated particle imaging (API) systems.
Sy, A. [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 USA and Department of Nuclear Engineering, University of California, Berkeley, Berkeley, CA 94720 (United States); Ji, Q.; Persaud, A.; Ludewigt, B. A.; Schenkel, T. [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States)
E-Print Network 3.0 - atomic beam frequency Sample Search Results
NLE Websites -- All DOE Office Websites (Extended Search)
laser and characterization of the atomic beam... is to measure the frequency dependent absorption of a laser beam intersecting the atomic beam. Depending... the ... Source:...
E-Print Network 3.0 - accelerated electron beams Sample Search...
NLE Websites -- All DOE Office Websites (Extended Search)
beams Search Powered by Explorit Topic List Advanced Search Sample search results for: accelerated electron beams Page: << < 1 2 3 4 5 > >> 1 KJKDec. 52002 Opportunities for Beam...
E-Print Network 3.0 - accelerator electron beam Sample Search...
NLE Websites -- All DOE Office Websites (Extended Search)
Summary: radiation facilities for biology and material sciences. Beam physics--study of beams in accelerators... high-brightness x-ray beams in synchrotron radiation facilities and...
Beam manipulation techniques, nonlinear beam dynamics, and space charge effect in high energy high power accelerators
We had carried out a design of an ultimate storage ring with beam emittance less than 10 picometer for the feasibility of coherent light source at X-ray wavelength. The accelerator has an inherent small dynamic aperture. We study method to improve the dynamic aperture and collective instability for an ultimate storage ring. Beam measurement and accelerator modeling are an integral part of accelerator physics. We develop the independent component analysis (ICA) and the orbit response matrix method for improving accelerator reliability and performance. In collaboration with scientists in National Laboratories, we also carry out experimental and theoretical studies on beam dynamics. Our proposed research topics are relevant to nuclear and particle physics using high brightness particle and photon beams.
Lee, S. Y.
Mechanics of nanoscale beams in liquid electrolytes: beam deflections, pull-in instability, and stiction
predicted by the two models is presented by varying the ion concentration, surface potential, ion size and distance of separation. The ratio of pressures is relatively independent of the distance of separation between the two surfaces. An elastic beam...
Lee, Jae Sang
Impact of high energy high intensity proton beams on targets: Case studies for Super Proton Synchrotron and Large Hadron Collider
Science Journals Connector (OSTI)
The Large Hadron Collider (LHC) is designed to collide two proton beams with unprecedented particle energy of 7�TeV. Each beam comprises 2808 bunches and the separation between two neighboring bunches is 25�ns. The energy stored in each beam is 362�MJ, sufficient to melt 500�kg copper. Safety of operation is very important when working with such powerful beams. An accidental release of even a very small fraction of the beam energy can result in severe damage to the equipment. The machine protection system is essential to handle all types of possible accidental hazards; however, it is important to know about possible consequences of failures. One of the critical failure scenarios is when the entire beam is lost at a single point. In this paper we present detailed numerical simulations of the full impact of one LHC beam on a cylindrical solid carbon target. First, the energy deposition by the protons is calculated with the FLUKA code and this energy deposition is used in the BIG2 code to study the corresponding thermodynamic and the hydrodynamic response of the target that leads to a reduction in the density. The modified density distribution is used in FLUKA to calculate new energy loss distribution and the two codes are thus run iteratively. A suitable iteration step is considered to be the time interval during which the target density along the axis decreases by 15%�20%. Our simulations suggest that the full LHC proton beam penetrates up to 25�m in solid carbon whereas the range of the shower from a single proton in solid carbon is just about 3�m (hydrodynamic tunneling effect). It is planned to perform experiments at the experimental facility HiRadMat (High Radiation Materials) at CERN using the proton beam from the Super Proton Synchrotron (SPS), to compare experimental results with the theoretical predictions. Therefore simulations of the response of a solid copper cylindrical target hit by the SPS beam were performed. The particle energy in the SPS beam is 440�GeV while it has the same bunch structure as the LHC beam, except that it has only up to 288 bunches. Beam focal spot sizes of ?=0.1, 0.2, and 0.5�mm have been considered. The phenomenon of significant hydrodynamic tunneling due to the hydrodynamic effects is also expected for the experiments.
N. A. Tahir, J. Blanco Sancho, A. Shutov, R. Schmidt, and A. R. Piriz
Neutron-deficient nuclei studied with stable and radioactive beams
Science Journals Connector (OSTI)
...radioactive nuclei compiled by W. Gelletly Neutron-deficient nuclei studied with stable and radioactive beams Neutron-deficient nuclei close to the proton...proton drip-line|radioactive beams| Neutron-deficient nuclei studied with stable...
contributed so much to the physics of colliding beams, theyto reap so little from the physics with colliding beams.Conference on High-Energy Physics, Vienna" September 1968 (
Pellegrini, Claudio
Nanostructure fabrication by electron and ion beam patterning of nanoparticles
Two modes of energetic beam-mediated fabrication have been investigated, namely focused ion beam (FIB) direct-writing of nanoparticles, and a technique for electrostatically patterning ionized inorganic nanoparticles, ...
Kong, David Sun, 1979-
Ion beam energy spectrum calculation via dosimetry data deconvolution.
The energy spectrum of a H{sup +} beam generated within the HERMES III accelerator is calculated from dosimetry data to refine future experiments. Multiple layers of radiochromic film are exposed to the beam. A graphic user interface was written in MATLAB to align the film images and calculate the beam's dose depth profile. Singular value regularization is used to stabilize the unfolding and provide the H{sup +} beam's energy spectrum. The beam was found to have major contributions from 1 MeV and 8.5 MeV protons. The HERMES III accelerator is typically used as a pulsed photon source to experimentally obtain photon impulse response of systems due to high energy photons. A series of experiments were performed to explore the use of Hermes III to generate an intense pulsed proton beam. Knowing the beam energy spectrum allows for greater precision in experiment predictions and beam model verification.
Harper-Slaboszewicz, Victor Jozef; Sharp, Andrew Clinton (A& M University, College Station, TX)
Applications of focused ion beam SIMS in materials science
Science Journals Connector (OSTI)
Focused ion beam instruments (FIB) can be used both for materials processing and materials analysis, since the ion beam used in the FIB milling process generates several potentially useful analytical signals such...
David S. McPhail; Richard J. Chater; Libing Li
Fermilab fixed target beams from the main injector
This paper discusses the following topics at Fermilab: 120--150 GeV beam extraction; link to switchyard; primary beam splits and transport; and experimental facilities at 120--150 GeV.
Childress, S.; Coleman, R.; Koizumi, G.; Malensek, A.; Moore, C.; Schailey, R.; Stefanski, R.; Stutte, L.
Engineering of Materials by Swift Heavy Ion Beam Mixing
Science Journals Connector (OSTI)
Ion beam mixing (IBM) is a phenomenon, at interface between two layers, in which the atoms of one layer mingle with the atoms of the other elements under the influence of ion beam traversal through them. When ...
D. K. Avasthi�
Thermal equilibrium theory of periodically focused charged-particle beams
A thermal equilibrium theory of periodically focused charged-particle beams is presented in the framework of both warm-fluid and kinetic descriptions. In particular, the thermal beam equilibria are discussed for paraxial ...
Samokhvalova, Ksenia R
Electron beam directed energy device and methods of using same
A method and apparatus is disclosed for an electron beam directed energy device. The device consists of an electron gun with one or more electron beams. The device includes one or more accelerating plates with holes aligned for beam passage. The plates may be flat or preferably shaped to direct each electron beam to exit the electron gun at a predetermined orientation. In one preferred application, the device is located in outer space with individual beams that are directed to focus at a distant target to be used to impact and destroy missiles. The aimings of the separate beams are designed to overcome Coulomb repulsion. A method is also presented for directing the beams to a target considering the variable terrestrial magnetic field. In another preferred application, the electron beam is directed into the ground to produce a subsurface x-ray source to locate and/or destroy buried or otherwise hidden objects including explosive devices.
Retsky, Michael W. (Trumbull, CT)
Electrons and gas versus high brightness ion beams
Review 1/11/05 beam Gas-Electron Source Diagnostic (GESD)and mitigation Gas-electron source diagnostic (GESD) [beam Measure each source of electrons Measure electron
Suppression of Beam-Ion Instability in Electron Rings with Multi-Bunch Train Beam Fillings
The ion-caused beam instability in the future light sources and electron damping rings can be serious due to the high beam current and ultra-small emittance of picometer level. One simple and effective mitigation of the instability is a multi-bunch train beam filling pattern which can significantly reduce the ion density near the beam, and therefore reduce the instability growth rate up to two orders of magnitude. The suppression is more effective for high intensity beams with low emittance. The distribution and the field of trapped ions are benchmarked to validate the model used in the paper. The wake field of ion-cloud and the beam-ion instability is investigated both analytically and numerically. We derived a simple formula for the build-up of ion-cloud and instability growth rate with the multi-bunch-train filling pattern. The ion instabilities in ILC damping ring, SuperKEKB and SPEAR3 are used to compare with our analyses. The analyses in this paper agree well with simulations.
Wang, L.; Cai, Y.; Raubenheimer, T.O.; /SLAC; Fukuma, H.; /KEK, Tsukuba
Methods for assisting recovery of damaged brain and spinal cord using arrays of X-Ray microplanar beams
A method of assisting recovery of an injury site of brain or spinal cord injury includes providing a therapeutic dose of X-ray radiation to the injury site through an array of parallel microplanar beams. The dose at least temporarily removes regeneration inhibitors from the irradiated regions. Substantially unirradiated cells surviving between the microplanar beams migrate to the in-beam irradiated portion and assist in recovery. The dose may be administered in dose fractions over several sessions, separated in time, using angle-variable intersecting microbeam arrays (AVIMA). Additional doses may be administered by varying the orientation of the microplanar beams. The method may be enhanced by injecting stem cells into the injury site.
Dilmanian, F. Avraham (Yaphank, NY); McDonald, III, John W. (Baltimore, MD)
End to End Beam Dynamics of the ESS Linac
The European Spallation Source, ESS, uses a linear accelerator to deliver the high intensity proton beam to the target station. The nominal beam power is 5 MW at an energy of 2.5 GeV. The individual accelerating structures in the linac and the transport lines are brie?y described, and the beam is tracked from the source throughout the linac to the target. This paper will present a review of the beam dynamics from the source to the target.
Eshraqi, M; Celona, L; Comunian, M; Danared, H; Holm, A S; M�ller, S P; Ponton, A; Stovall, J; Thomsen, H D
Proposal of physics with exotic beams at Oak Ridge
A facility to produce proton-rich radioactive beams for nuclear structure and astrophysics experiments is proposed. This Oak Ridge Exotic Beam (OREB) facility is based on two existing accelerators. Beams of mass up to 80 can be accelerated to energies of about 5 MeV/nucleon. It will provide opportunities to study new areas in nuclear physics and astrophysics that are not available with the use of stable beams. 3 figs.
Lee, I-Yang.
Laser and Particle Beams http://journals.cambridge.org/LPB
Laser and Particle Beams http://journals.cambridge.org/LPB Additional services for Laser, J. Limpouch, R. Liska and P. Váchal Laser and Particle Beams / Volume 30 / Issue 03 / September 2012 of annularlaserbeamdriven plasma jets from massive planar targets. Laser and Particle Beams,30, pp 445457 doi:10.1017/S
Liska, Richard
Mercury Beam Dump Simulations Tristan Davenne Ottone Caretta
Mercury Beam Dump Simulations Tristan Davenne Ottone Caretta STFC Rutherford Appleton Laboratory, UK 2nd Princeton-Oxford High Power Target Meeting 6-7 November-2008 #12;Mercury beam dump design from NUFACT Feasibility Study #12;Peter Loveridge, November-2008 Mercury beam dump design from NUFACT
McDonald, Kirk
Mercury Beam Dump Simulations Tristan Davenne Ottone Caretta Chris Densham
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electron beams will demand better accur