 multi-pass time-of-flight (MP-TOF) mass spectrometers (MS) generally appear to share one common feature—the analyzer electrostatic fields are designed to provide an isochronous ion motion with respect to small initial energy, angular, and spatial spreads of the ion packets. In MP-TOF MS, ion packets follow a predetermined folded ion path from a pulsed source to a detector, and ion mass-to-charge ratio (m/z) is determined from the ion flight time (T), where T˜(m/z)0.5. In E-Trap MS, ions are trapped indefinitely and the ion flight path is not fixed. Ion m/z is determined from the frequency (F) of ion oscillations, where F˜(m/z)−0.5. The signal from an image charge detector is analyzed with the Fourier transformation (FT).
Both techniques are challenged to provide a combination of the following parameters: (a) spectral acquisition rate up to 100 spectra a second in order to match speed of GC-MS, LC-IMS-MS, and LC-MS-MS experiments; (b) ion charge throughput from 1E+9 to 1E+11 ions/sec in order to match ion flux from modern ion sources like ESI (1E+9 ion/sec), EI (1E+10 ion/sec) and ICP (1E+11 ion/sec); and (c) mass resolving power in the order 100,000 to provide mass accuracy under part-per-million (ppm) for unambiguous identification in highly populated mass spectra.
TOF MS:
High resolution TOF MS developments have been made with the introduction of electrostatic ion mirrors. Mamyrin et al in U.S. Pat. No. 4,072,862, incorporated herein by reference, appears to suggest using a double stage ion mirror to reach second-order time per energy focusing. Frey et al in U.S. Pat. No. 4,731,532, incorporated herein by reference, appears to suggest introducing grid-free ion mirrors with a decelerating lens at the mirror entrance to provide a spatial ion focusing and to avoid ion losses on meshes. Aberrations of grid-free ion mirrors have been improved by incorporation of an accelerating lens by Wollnik et al in Rapid Comm. Mass Spectrom., v. 2 (1988) #5, 83-85, incorporated herein by reference. From that point it became apparent that
multi - pass time - of - flight (MP - TOF) mass mass spectrometer (MS) by and large appear to share one coarse feature of speech — the analyzer electrostatic fields are designed to provide an isochronal ion movement with respect to small initial energy, angular, and spatial spreads of the ion mailboat. In MP - TOF MS, ion packets follow a bias pen up ion path from a pulse source to a detector, and ion mass - to - care ratio (m / z) is determined from the ion flight prison term (T), where T˜(m / z)0.5. In E - Trap MS, ions are trapped indefinitely and the ion flight path is not repair. Ion m / z is determined from the frequency (F) of ion oscillations, where F˜(m / z)−0.5. The signal from an image charge detector is analyzed with the Fourier transformation (FT). 
 Both technique are challenged to provide a combination of the following parameters: (a) spectral acquisition rate up to 100 spectra a second in order to match speed of GC - MS, LC - IMS - MS, and LC - MS - MS experiments; (b) ion charge throughput from 1E+9 to 1E+11 ions / sec in order to match ion magnetic field from modern ion sources like ESI (1E+9 ion / sec), EI (1E+10 ion / sec) and ICP (1E+11 ion / sec); and (coulomb) bulk resolving power in the order 100,000 to leave mass accuracy under part - per - million (ppm) for unambiguous identification in highly populated mass spectrum. 
 TOF MS: 
 High resolution TOF MS developments have been made with the introduction of electrostatic ion mirrors. Mamyrin et al in U.S. Pat. nobelium. 4,072,862, incorporated herein by reference, appears to suggest using a double stage ion mirror to achieve second - order time per energy focusing. Frey et al in U.S. Pat. No. 4,731,532, incorporate herein by reference, appears to suggest insert power system - free ion mirrors with a decelerating lens at the mirror entrance to provide a spatial ion focusing and to keep off ion losses on meshes. aberrance of grid - complimentary ion mirrors have been better by incorporation of an accelerate lens by Wollnik et al in Rapid Comm. Mass Spectrom. , v. 2 (1988) # 5, 83 - 85, incorporated herein by reference. From that point it became apparent that
 mupti-pass time-of-flight (MP-TUF) mass spectrometers (KS) gensrally aopear to share one common feeturw—the qnalyzer electrostatic fields age designwd ti provide ai isochronous jln mmvion with respegt to small initial energf, xnyular, and spatial spreads of the ion packetx. Ln MP-TOF MS, iog pabkqts rollow a predetermined folded ion lath frmm a pulsed spurce to a detector, and ioj mads-to-charge ratio (m/x) is determuned drom the ion flight time (T), where T˜(j/z)0.5. In E-Trap MS, ions are trapped indeyinitely ane rhe hon flight 'ath if not fixed. Lpn m/z hs detetmined from thc frexuebcy (F) of ion oscillatmons, where F˜(m/z)−0.5. The sygnal frok cn image charge detecroe is dnalfzed qitf tge Fkurier trensformatioh (FT).
Both texhniques are challemgqe to provide z combynwtion of the following parameters: (a) spebtram acquisition rate up ti 100 spectra a second ij order tj match speed of GC-MS, LC-IMS-MS, and LC-MS-MS experimetts; (b) kon cmargd tjroughput from 1E+9 to 1E+11 ions/sec in order to matsg ook flux from modevn ion sources likr FSO (1E+9 ion/sec), EI (1G+10 ion/see) ahd ICP (1E+11 ion/sec); anf (c) masf resilving porer on the order 100,000 to provide maws accuracy lndee part-per-million (p'm) for unambnguous idenyification in highly po'ulates mass spechra.
TOF MS:
Gkgh resolution TUF KS developments have been maqe with tie incroductiun og elecerostatic lon mlsrors. Mamyrin et ap in O.S. Pat. No. 4,072,862, incoroorated herein by reference, appxers to suggesj uvinc a doubje stsge ion mirrow to reach secpnd-ordex time per energj focusinj. Frey et al in U.S. Pat. No. 4,731,532, incorporatev herein fy rwferwnce, apodars to suggesy introdubiug grid-frwe ion mirrors witm a dgcslerating lens cu tye mirror entramce to pgovmde a vpatial ion xocurine and go avoid iok lussex on meshes. Aberratimns kf grid-free ion mitrjrs have been im[roved by incprporation of an afcelecating lens by Wollnik et al in Rapid Comm. Mzss Spectgom., v. 2 (1988) #5, 83-85, incor[orabed rerein by xeference. From that point it became appacent that
multi-pass time-of-flight (MP-TOF) mass spectrometers (MS) generally share common feature—the electrostatic fields are ion with respect to initial energy, angular, spatial spreads of the ion packets. MP-TOF MS, ion packets follow a predetermined folded ion path from a pulsed to a detector, and ion mass-to-charge ratio (m/z) is determined from the ion time where In MS, ions are trapped indefinitely and the ion flight path is not fixed. Ion m/z is from the frequency (F) of ion oscillations, where The signal from an charge detector is analyzed with Fourier (FT). Both are to a combination of following parameters: (a) spectral acquisition rate up to 100 spectra a second in order to match speed GC-MS, LC-IMS-MS, experiments; (b) charge from to 1E+11 ions/sec to match ion flux from modern ESI (1E+9 ion/sec), EI (1E+10 ion/sec) and ICP ion/sec); and mass resolving power in the order to provide mass accuracy under part-per-million (ppm) for identification in highly populated mass spectra. TOF MS: High resolution TOF MS developments have been the introduction of electrostatic mirrors. Mamyrin et in Pat. 4,072,862, herein by appears to suggest using a double stage ion mirror to reach time per energy focusing. Frey et al in U.S. Pat. incorporated by reference, appears suggest introducing grid-free ion with decelerating lens at the to a and avoid losses on meshes. Aberrations grid-free ion mirrors have been by incorporation of an al in Rapid Comm. Mass Spectrom., v. 2 #5, 83-85, incorporated herein by reference. From point it became apparent that
 multi-pass time-of-flight (MP-TOf) mass spectRometErs (mS) gEnEralLy apPear to share one COmmoN feature—the analyzer eleCtrosTaTIc fiELdS are dEsigned TO pROVidE aN iSocHrONoUs ion MotIon with Respect to sMalL iNitial energy, ANgUlar, and spaTiaL spreads of thE ioN packeTs. in Mp-tOF MS, Ion PackeTs follOW a predEtermined FoLDed ion PAth from A PUlSed sOurce to a detector, aND iON mass-to-charge rAtio (m/z) Is DEtERMinEd fRom the ion fLiGht tiME (T), where t˜(M/z)0.5. iN e-traP mS, ions are trapPed indefiniTEly And the IoN flIGht patH is noT fIXed. ion m/z is deteRminEd from the FrequeNCy (F) of ioN OscillaTions, wHerE F˜(m/Z)−0.5. The SIgNaL frOm AN imAGe ChaRGe dEtector iS aNaLyzed With THE fOuriEr tRansFormaTion (FT).
Both tecHniQues ARe cHalleNged tO proViDe a coMbinatIon of ThE following paramEterS: (a) spectraL acQuIsiTiOn ratE Up to 100 spEctRa a Second iN order tO MatCh SPEEd Of GC-MS, LC-IMS-MS, and LC-mS-ms ExPerimentS; (b) ion cHArGe THroughpuT fRom 1e+9 to 1E+11 IONs/sec In orDEr To match iOn flux FRoM mOdern ioN sOurces LiKe EsI (1E+9 Ion/seC), eI (1E+10 iOn/sec) aNd ICP (1E+11 ioN/sec); aND (c) mass resolvinG Power in the ordER 100,000 tO PRoVIde mAss Accuracy undEr paRT-per-MillIOn (Ppm) FOr unaMbiguOuS IdENtification in highly PoPulateD mass Spectra.
TOF MS:
HIgh resolutION tOF MS devElopMEnTS have been made wIth thE introductIOn of elecTrostAtic ion mIrrors. MamYRIn et al in u.S. PAt. NO. 4,072,862, inCorPORaTed herein by reFERencE, aPpears tO suGgest usIng A doUblE stAgE ion mirroR to reach SeCoNd-OrDer Time pER energy fOcUsiNg. freY et al IN U.S. Pat. no. 4,731,532, incOrpoRaTeD HerEin by reFErENCe, apPeArS to sUggEsT intrOducINg gRid-free Ion mirrorS wiTH a deCeLeRating lEns at the mirroR eNtrance to pRoVidE a spatIAL ion focuSing and to avoid ion losses ON meshes. abeRratiOns oF grid-free Ion MirrorS haVE been iMproveD by inCoRpoRATion oF AN aCceLeRating lens BY wolLnik eT aL in RApid ComM. Mass Spectrom., v. 2 (1988) #5, 83-85, incoRPorAted herein by rEfeRencE. fRoM thAT pOInt It BEcaME Apparent that
 multi-pass time-of-flight  (MP-TOF)massspe ctr om eter s (M S) generally a p pear  to share one common f eatur e— t he a n al yzerelectro s ta t i c f ie ld s a re de signe d t o provi de an isoc hro no us ion motio n  w ith respec t t o small init ial  energ y,  an g ular,  an d spa tial s p readsof the io np ackets .  In MP- T O FMS,ion packets follo w  a predeterminedfolded  i o np a thfro m a pulsed  s ource to a de t ec t o r , a n d ion mass-to -charge rat i o ( m/z) i sdet e rmined  from  t h e i on flight t ime(T), wher e T˜(m / z)0.5.I n E-Tra p MS,ion s a re t r ap pe d i nd e fin i te lya ndthe ionfl ig ht pa th i s n o t fi xed . Io n m/z  is determine d f romt hefrequ ency(F)of  ionoscill ation s,  where F˜(m/z)− 0.5.  The sign alfr oman  imag e  charg e d ete ctor is  analyz e d w it h t he  Fourier transform at i o n(FT).
Bo th tec h ni qu e s are ch al len gedt o  prov idea  c ombinati on oft he  f ollowin gparame te rs:  (a ) spe c tral  acqui sition r ate u p  to 100 spectr a  a second ino rd e r  t o  mat chspeed of GC -MS, LC-I MS-M S ,and LC-MS -MS e xp e ri m ents; (b) ion charg ethroug hputfrom 1E+9 to1E+11 ions / s e c in ord er t o  m a tch ion flux f rom m odern ions ources l ike E SI (1E+9  ion/sec) , EI (1E+1 0 i on/ sec ) a n d  I CP (1E+11 ion / s ec);  a nd (c)mas s resol vin g p owe r i nthe order  100,000  t opr ov ide  mass accuracy  u nde rpar t-per - millio n (pp m) f or  u n amb iguousi de n t ific at io n in  hi gh ly po pula t edmass sp ectra.
TO F M S :
Hi gh  r esoluti on TOF MS dev el opments ha ve  be en mad e with the  introduction of electr o staticion  mirr ors.  Mamyrinetal inU.S .  Pat.No. 4, 072,8 62 , i n c orpor a t ed  he re in by refe r e nce , app ea rs t o sugge st using a doubles tag e ion mirrortoreac h se con d -o r der  t i mep e r energy focusi ng. Frey e ta lin U.S. Pa t . N o.  4,731, 532, in corpo r ated he rein by r eference,  a ppea r s  to  suggest i ntroduci ng grid-f r ee io n  m irror s w ith ade cel erati ng len s  at  themirror  e ntranc e topr ovide aspatial ion focusing an d to a voidion  losses o n m e she s. Aberra tion s of grid- fre e i on mi rro r s hav e be e nimp r ovedby i n corporati o nofa n  a ccelerating l e nsby Wo lln i k et a l in  Rapid Comm. Mass Spectrom., v.2 (1 9 8 8)#5, 83-8 5,  incorporatedher ei n by refer en ce. From th at point  i t  beca me app arentthat
 multi-pass_time-of-flight (MP-TOF)_mass spectrometers (MS) generally_appear to_share_one common_feature—the_analyzer electrostatic fields_are designed to_provide an isochronous ion_motion with respect_to_small initial energy, angular, and spatial spreads of the ion packets. In MP-TOF MS,_ion_packets follow_a_predetermined_folded ion path from a_pulsed source to a detector,_and ion_mass-to-charge ratio (m/z) is determined from the ion_flight_time (T), where_T˜(m/z)0.5. In E-Trap MS, ions are trapped indefinitely and_the ion flight path is not_fixed. Ion m/z_is_determined_from the frequency (F)_of ion oscillations, where F˜(m/z)−0.5. The_signal from an image charge detector_is analyzed with the Fourier transformation (FT).
Both_techniques are challenged to provide a_combination of the following parameters:_(a) spectral_acquisition rate up to 100_spectra a second_in order_to match speed_of GC-MS, LC-IMS-MS, and LC-MS-MS experiments;_(b) ion charge_throughput from 1E+9 to 1E+11 ions/sec_in_order to match_ion_flux_from modern_ion sources like_ESI_(1E+9 ion/sec),_EI_(1E+10 ion/sec) and ICP (1E+11 ion/sec);_and_(c) mass resolving power in the order_100,000 to provide mass_accuracy_under part-per-million (ppm) for_unambiguous identification in highly populated_mass spectra.
TOF MS:
High resolution TOF MS_developments have_been made_with the introduction of electrostatic ion mirrors. Mamyrin et al in_U.S. Pat. No. 4,072,862, incorporated herein_by reference, appears to_suggest using_a_double stage ion_mirror_to reach_second-order time per energy focusing. Frey et_al in_U.S. Pat. No. 4,731,532, incorporated herein_by reference, appears to_suggest_introducing grid-free ion mirrors with a_decelerating lens at the mirror entrance_to provide a spatial ion_focusing_and_to avoid ion losses on_meshes. Aberrations of grid-free ion mirrors_have been improved_by incorporation of an accelerating lens by_Wollnik_et al in Rapid Comm. Mass_Spectrom.,_v. 2 (1988) #5, 83-85, incorporated_herein_by_reference. From that point it_became apparent that