In the early 1970s there was a group of five academic staff in the School eager to learn more about particle-solid interactions. They had by then equipped themselves intellectually and with the machines of experimental physics to carry out research in this field in a systematic way with projects that would fill in gaps in current knowledge. Around them students had clustered who were learning how to carry out research and enlarging their own understanding of the physical sciences. These students were attending lectures, reading and carrying out original experiments. The group had attracted postdoctoral fellows pursuing the more advanced topics and distinguished academic visitors, often from overseas, wishing to gain experience at Sussex and, perhaps, to build collaborative projects with their own groups. Altogether there were about 30 people involved in the group at any time in the mid 1970s.
A decade earlier four of these five were themselves postdoctoral fellows doing advanced research overseas alongside leading scientists of the day. To name them, Derek Palmer was in the Ecole Normale Supérieure, Paris, Mike Lucas was in the Argonne National Laboratory in Illinois, John Venables was in the University of Illinois at Urbana and Peter Townsend was in the Brookhaven National Laboratory in New York State. The fifth man was Michael Thompson, occasionally to be found visiting these labs and others like them, sometimes extending his visits over many months to engage in collaborative research. His first job after graduating in 1953 had been in the Atomic Energy Research Establishment at Harwell, but then in 1965 he was appointed to a Chair of Experimental Physics in Sussex. At Sussex he was warmly welcomed by John Venables, who had earlier returned from Illinois to a Lectureship in Physics, and by Robert Cahn who had been appointed to the Chair of Materials Science in the School of Applied Sciences and had himself worked in Harwell.
Another member joined the group shortly afterwards. His name was Barry Farmery and he had worked with Michael Thompson at Harwell in building accelerators and running experiments. At Sussex he became responsible for installing and operating the accelerators, managing a team of technicians, giving advice on the use of ion beams and frequently becoming involved as a respected collaborator in experiments.
The historical context of British science in the 1950s and 1960s is of relevance to this history because each member had graduated from a British university. After the Second World War the country had its ancient universities and it had the late-Victorian civic universities. All had increased in size only to the point where about 5% of pupils leaving school could go on to university education. The country in response to military needs had created vast establishments for research and development in aviation, jet propulsion, electronics, radar, chemical and biological weapons and atomic weapons. Besides this there were peaceful needs being met in large central laboratories, for example in medical research, telecommunication, public health and the newest was in atomic energy. To exploit discoveries many large industrial companies had their own research and development laboratories. By the mid 1950s the policies of the government were to shift some work from their own labs to those industries or, if the research was of a more fundamental kind, encourage the universities to take it on. But if none of the three wished to fund a topic it would be closed down.
The government had also recognised a shortage of university places, firstly because the wartime recruits into military service returned as civilians wishing to take up the higher education they had missed and secondly because of the wishes of school-leavers in a burgeoning population of young people. A committee of enquiry chaired by the eminent educationalist Lord Robbins recommended that higher education should be open to all with the ability to benefit from it. The implication was that the State would pay, in grants to the universities and grants to the students for their fees and maintenance. It was decided, momentously, to accept this doctrine, to expand existing universities and establish six new universities of which Sussex was one.
The policy on government labs had meant for young graduates aspiring to research that places like Harwell would be less likely to employ them. On the other hand the British universities had been full. It had seemed that careers for young British scientists might better be pursued in America. Four of this group had already gone overseas to work and could well have stayed. The fifth was looking at an attractive US offer and wondering whether to emigrate. But now the new university policy changed the prospect and the UK was on offer too. So it was that the group was enabled to form.
The group could have had several labels that included: ionising radiation in matter, or atomic collisions in solids, or radiation damage and defects in solids, to give but three examples. But to catch up as many themes as possible without writing a paragraph ‘Particle-Solid Interactions’ had to do and that was what the group called itself for a visit by an assessment panel of the Science Research Council in 1975.
Some paragraphs follow in which the interests of the five members of the group are summarised. Each knew that he could not cover every aspect of knowledge in such a broadly defined field but would devise experiments and theories to fill interesting gaps in his own knowledge. If that gap might also be of interest to another member of the group it might be given priority, or collaboration might develop or a project might transfer from one member to another.
The group united around a willingness to share interests, a desire to explore zones of scientific ignorance and to map them for others to follow. One way that unity found expression was in regular seminars attended by staff and students where someone would talk about the current state of their research and expect discussion. Whatever its breadth of interest the scope of the group’s research was limited by equipment, for it had built or purchased a set of tools that could serve some purposes but not others. The members also had options to use equipment elsewhere, but by 1975 it was unlikely that they could add much to those expensive resources. Their particle toolkit included two electron microscopes, a 20kV pulsed ion accelerator for heavy ions, a 300kV ion accelerator and a 3MV van de Graaf accelerator, for ions or electrons, housed in a specially shielded building. Later, a small 45kV ion implanter was added. This was followed in the 1990’s by a high current 200 kV implanter which was mostly used on a commercial project to explore changes in the surface properties of glass in areas as diverse as production of car mirrors, anti-reflective coatings and reflective sunglasses.
The fundamental scientific question for the group was how are the structure and properties of condensed matter affected by an environment of ionising radiation? That question grows upon roots in the technologies of electronics, nuclear energy and medicine. Besides the intrinsic scientific value of the answers, applications were inferred that could benefit everyone.
The impact of ions upon a surface in a vacuum has a bad history of spoiling the performance of electrical machines. For example vacuum devices like fluorescent tubes for lighting and electron tubes for television are spoiled by atoms being sputtered by ion impact from electrodes and condensing inside the tubes to prevent light from being emitted. The newer solid-state devices in electronics or power engineering are made of semiconductor crystals whose electrical conductivity is engineered by creating defects (eg. by adding minute concentrations of phosphorous to silicon to make a dilute alloy) But if the device is exposed to ionising radiation crystal defects may be created that could inhibit its performance. Paradoxically, ion impact can have effects that create technical opportunities. The bad guy appears to be good in processes for making modern microcircuits like sputtering, ion implantation and radiation damage.
In the development of nuclear energy for peaceful purposes it was soon discovered that the useful life of reactor materials is limited by radiation damage. In fission reactors fuel rods swell, ductile metals become brittle and by storing energy graphite moderators might unexpectedly overheat. Fusion reactors have similar problems but in addition atoms are sputtered by particle impact from their internal walls which may inhibit the desired fusion. In 2010 the technology of atomic energy still needs research into these effects as the third generation of fission reactors and the first generation of fusion reactors are being built.
The early style of experimentation in nuclear science was to irradiate a sample with neutrons in a reactor and take this back to the lab for measurement or, with more difficulty, do the measurements inside the reactor. But at Harwell in 1958 a ground-breaking move had been made when a small accelerator of heavy ions was built to simulate irradiation by neutrons. Argon ions having energies of 50 keV bombarding a sample of copper will produce the same sort of atomic recoils as 2 MeV neutrons and the experiments become better controlled and easier to analyse. For example one could create damage in thin crystals that could be seen as disordered regions in an electron microscope. Or atoms sputtered from the crystal surface could have their distribution of energy analysed knowing that this carries information about collision cascades inside the irradiated solid.
In both semiconductors and metals many valuable experiments on radiation damage had been done in the 1950s and 60s with MeV electron beams from accelerators, but the new heavy ion accelerators opened a new door. In addition to damage to the structure they could also implant ions of another chemical element and a new way of making dilute alloys was invented. It had the attractive new feature of being able to implant to a depth that was controlled by the ion energy. Entirely new classes of electronic device followed, as did metal surfaces with increased resistance to wear.
When the group of five assembled in Sussex during the 1960s some of these things had just been done at the places they came from. But prospects were open and many ideas were left to be explored. To show how the mosaic of members’ interests made a picture and how the borders and gaps in that picture became places for conjecture or research, a brief summary of the achievements and interests of the five academic leaders follows below.
John Venables, who arrived in 1963, had contributed for some years to the study of crystal defects and crystal growth by the diffraction of an electron beam in an electron microscope. Because defects perturb the diffraction process the image of crystal in the microscope can show their position and may even allow their structures to be resolved. At high enough energies the electrons of the microscope beam can themselves produce radiation damage whose structures may be studied in the same instrument.
It was a powerful technique and especially so because John Venables had modified his microscopes, uniquely, to permit the sample to be cooled to very low temperature, bombarded with low energy ions to create visible defects, or have vapours condensed upon it. Major contributions were being made by his students by 1975 to our understanding of the processes by which a vapour condenses into a crystalline film upon a crystalline substrate where, initially very thin mono-layers of atoms cover the entire surface then thicker islands form whose growth is fed by diffusion from the mono-layer.
Michael Thompson arrived in 1965 having studied at Harwell the way in which the kinetic energy of a particle creates defects in the solid. It can do this through a cascade of atomic collisions spreading out from the point of impact or the ionisation around the particle track. A related effect is the kinetic sputtering of atoms through the surface that could be studied by measurement of their momentum. That is to say that one measures both the angular distribution and the energy distribution. A pulsed ion beam and a time-of flight apparatus had been devised for this purpose. Theoretical work on the statistics of collision cascades and the effect of the surface upon the emerging atoms led him in 1967 to a formula E/(E + Eb)3 for the energy distribution and this was being found in many experiments ( Eb is the binding energy of an atom to the surface). It is often referred to as the Thompson formula in the literature. From the fact that the distribution becomes like 1/E2 when E >> Eb one infers that the number of atoms permanently displaced from their sites by a collision cascade must be proportional to the energy in the first collision. This is a result of great importance in radiation damage. Departures from this sputtering formula were being discovered in the case of very energetic and heavy ions or in the case of single-crystal targets. These were hot topics in 1975 that revealed the presence of literally hot spots around the site of the collision cascade, and showed how the crystal structure itself imposes structure upon the cascade.
In the early 1960s a related phenomenon had been discovered called channelling. In this a particle entering a crystal in a direction close to a prominent crystal axis and on a trajectory that entered the surface in the spaces between the atomic rows that define that axis, travelled long distances bouncing back and forth amongst those rows. It was manifested by exceptional ranges of ions of any mass when their beams were aligned within some critical angle of an axis. This angle was typically a few degrees and proportional to [Z1Z2/E]1/2 , here Z1 and Z2 are the atomic numbers of particle and solid respectively and E is the particle’s kinetic energy. The penetration experiments with light ions had been done at Harwell by Michael Thompson and his colleagues, the heavy ion penetration by a Canadian group led by John A Davies and the theory of the critical angle came from Denmark’s Jens Lindhard. The effect of channelling was also seen in the reflection or back-scattering of ions where minima were seen in the reflected fraction of the beam whenever the beam was aligned with either rows or planes. There was then both axial and planar channelling and many groups entered into the study of this phenomenon and its applications. High energy electrons and positrons were joined in too.
In a side-shoot of this field Michael Thompson had scattered ions at grazing incidence from the flat surface of a crystal whilst on a visit to Canada. A significant number were reflected as if by a mirror – the ion’s momentum perpendicular to the surface being reversed -. His students were studying this process further and devising means by which the structure and composition of surfaces could be determined. The theory of channelling was also to be refined by these observations and linked to experiments, about to be described, by one of Derek Palmer’s students.
Michael Thompson’s interest in the penetration of heavy ions into the solid was being pursued in 1975 by a student measuring the distribution of depths below the surface at which these ions lodged. The method used was to back-scatter MeV H+ or He+ ions into an energy sensitive detector and from their energy distribution unfold the depth distribution. The species of heavy ion was varied, or the kinetic energy, or the angle of incidence. From the data of many such experiments it was hoped to test and refine theories current at that time or at least provide empirical data for technology.
Derek Palmer’s interests were mainly in irradiation effects and defects in crystalline semiconductors, but he studied also irradiation-induced defects in the body-centred metals iron and niobium. The former had great practical importance for electronic devices and the latter provided valuable information relating to nuclear-reactor technology. He showed how to use channelling of MeV protons and helium ions, in association with Rutherford back scattering and proton-induced and 3He-induced nuclear reactions, as an analytical tool to detect defects created by radiation damage or ion implantation and to analyse their structures and properties. A valuable fundamental feature, exploited in the work, of irradiation by light energetic ions is that the main ion-atom collision process is via nuclear-nuclear Coulomb interactions, and therefore that most of the collisions create lattice defects that are simple interstitials and vacancies. Clear comparisons with electron-irradiation studies elsewhere could thence be made.
An important innovation in the work by Derek Palmer was his setting up, on a beam line of the 2.0 MV Van de Graaff ion accelerator, of an experimental facility that allowed angle-resolved ion-channelling, in-situ irradiation and property measurement of semiconductor and metal samples at temperatures down to close to 4K. That facility allowed irradiation-induced defects to be investigated before their thermally induced diffusion. Changes in the defect structures caused by heating were then studied in detail. For semiconductors, his investigations demonstrated that ionisation by fast (200 keV to 2.0 MeV) light ions could damage the lattice structure in silicon and germanium, additional to the disruption due to the nuclear-nuclear elastic collisions. Examples of particular results for metals (in work supported in part by AERE, UK) were the findings that the lattice sites of molybdenum atoms dissolved in iron and of oxygen atoms in niobium could be changed by their trapping of irradiation-induced point defects, and that that also allowed quantitative investigation of the thermally induced mobilities of the defects.
The phenomenon of channelling had been earlier studied by Derek Palmer in crystals of quartz. With a student he was in 1975 unravelling the fine detail of how channelled trajectories in another oxide crystal MgO change their direction from inter-axial to inter-planar. It is a process called scattering in the transverse plane, where this plane is perpendicular the crystal axis concerned, in which patterns emerge which can focus trajectories upon certain rows of atoms. This was being related by Derek Palmer’s student to the surface-scattering experiments of Michael Thompson and his students.
It became clear, however, that the ion-channelling technique was not sensitive to the very low concentrations of lattice defects that could strongly affect the crucial electrical properties of semiconductors, and so Derek Palmer’s research moved into use of the DLTS (“Deep Level Transient Spectroscopy”) technique that investigates defects by their trapping and emission of electrons and holes in the semiconductors. Again the creation and properties of irradiation-induced defects at both cryogenic and higher temperatures needed to be investigated, and an in-situ DLTS cryostat was designed and was installed on a further ion-beam line of the Van de Graaff accelerator. Because the use of proton-irradiation-induced defects to produce high resistivity regions in GaAs devices and integrated circuits was of much technological interest, Derek Palmer developed a close research link with the Philips Research Laboratory at Redhill, and he and his research students made detailed in-situ DLTS and associated electrical investigations on lattice defects in GaAs and on the related alloys Al(x)Ga(1-x)As and In(x)Ga(1-x)As. Indium phosphide was also of industrial interest, and DLTS investigations of light-ion created defects in that semiconductor were made in later work. The work on GaAs etc and on InP produced valuable new results for irradiation-induced defects concerning their electronic energy levels, their thermal annealing properties and their natures.
The experimental ion-irradiation / DLTS facility was subsequently supplemented by a rig that allowed in-situ uniaxial stress to be applied to semiconductor samples at temperatures down to about 10K before and after proton and helium ion irradiations. The studies on n-type GaAs showed that uniaxial stress applied along the <100> and <110> crystallographic directions splits the electronic energy levels of each of the well known irradiation-induced defects E1, E2 and E3 into two levels of equal populations. Those experimental data showed that each of those lattice defects contains a single <111> crystallographic axis (ie, has C3v symmetry) and strongly suggested that E3 is an arsenic Frenkel defect, ie an arsenic interstitial-vacancy close pair, and that E1 and E2 may also be arsenic Frenkel pairs, but with different interstitial-vacancy separations. Those were the first ever uniaxial-stress studies on any irradiation-induced defect in GaAs.
Mike Lucas, before he joined the group, had worked on the properties of defects in metals after irradiation with neutrons. His new interest was in the disturbance of the electrons in a solid by a very fast moving ion. He passed his ion beam through a thin solid and detected the electrons that emerged from the surface. These had their momentum analysed and it was found, surprisingly, that downstream of the foil, in the exact direction of the ion beam, the most probable speed of the electrons was the same as the speed of the ions. It was a result of great interest to theoreticians, several whom joined our group as collaborators and became frequent visitors. A new theory of the collision processes that excite electrons around a particle track was developed. The process responsible for the electrons emitted at the speed of the ions was called ‘charge capture to continuum states’.
Peter Townsend had a broader interest in ionisation by radiation. He studied insulating solids that were often crystalline, sometimes glassy and nearly always transparent. Optical properties and their relationship to crystal defects is a recurring theme in his publications (e.g. Can one tailor optical properties?). He had just made a major contribution to theories of radiation damage by studying the creation of defects and sputtering of ions from ionic crystals like potassium iodide by irradiation with slow electrons. The electrons lacked the momentum to displace an atom by direct collision Even more surprising had been his prediction and demonstration that even ultraviolet light could sputter ions from the surface. The model correctly explained why the sputtering patterns of alkali and halogen ions were different. The theory of this process was a fascinating example of the radiation exciting an electron and this potential energy being transferred into kinetic energy on the nucleus of a single ion.
The phenomenon of thermo-luminescence was another of Peter Townsend’s interests, especially when related to defects that could be introduced by radiation or by ion implantation. Crystals like lithium fluoride, which have important uses as radiation dosimeters in medicine and radiological protection, were being studied in 1975 and he built equipment to measure the emission spectra. This information was lacking from most other thermoluminescence research groups. As a consequence, Sussex stayed in a lead position in this field for the next 30 years. In the late 1990’s this same type of equipment opened a novel route to detection of phase transitions, both of crystals and nanoparticle inclusions.
A third group of Peter Townsend’s experiments used high energy ions to damage the structure of glasses in a controlled layer beneath the surface. The depth of the layer was made comparable to the wavelength of light and he thus constructed optical waveguides. This work was to be of immense significance in developing the field of opto-electronics for smaller computers and optical fibres as transmission lines for telecommunication. It may be noted that Mike Thompson arranged a meeting with Charles Kao when Kao worked on this topic at the Standard Telecommunication and Cables Laboratories in the 1960s. At that point the potential of optical fibres had not been recognised by industry and the Sussex group were interested to see if ion implantation could be included in the processing. For the fibres this was not possible, but later, in 2009, Charles Kao received the Nobel Prize for Physics for making optical telecommunications possible. There was also some glory reflected on Sussex as this meeting prompted Peter Townsend to devise an ion implantation route to make optical waveguides in insulating crystals. This was a semi-universal route which has now been widely used in many more than 100 materials for waveguide lasers, non-linear optics and key items of modern photonics. Physics is a small community, as Townsend visited the Chinese University of Hong Kong in 1992 as the Wei Lun Professor whilst Professor Kao was Vice-Chancellor there.
A collaborative project was set up with Professor Cahn’s Materials Sciences group in the School of Applied Sciences. Rob Wilshaw used ion implantation of H+ ions to assist the fracture of quartz crystals under mechanical stress. It was shown that even at low energies the implantation softened the quartz significantly. In application, it was hoped that the effect might reduce the energy expended in the crushing of minerals in the mining industry (RTZ).
In this section the titles of the lecture courses open to the graduate students lays out the subject matter of our interests. A full list of all the staff serving in the group up to 1980 is given in Appendix A. A detailed picture of the research and its development over time can be gleaned from Appendix B which gives the names of all the graduate students, the titles of their theses and the names their supervisors. The onward careers of those early students are indicated rather briefly, as for many of them, details of their later lives are frequently unknown. However, over the subsequent years many of the Sussex graduates from the ion implantation group have made significant contributions to Physics and Materials Science. Of those who stayed in Academic environments there are numerous Professors, Head of Department, Deans and Vice Chancellors.
The Physics Department taught all its research students in their first year enough additional physics to prepare them for their task. Short courses of lectures advanced their knowledge of quantum mechanics for example. More technical instruction was given to equip the students for using central computers, libraries and workshops. Where there were large enough groups to make it economical in staff time, specialised courses were given on that group’s subject, such as Condensed matter at low temperature, atomic and laser physics and particle-solid interactions.
‘Atomic collisions in solids have attracted a great deal of attention in recent years. Processes such as atomic collision sequences and cascades, particle channelling, electron excitation and ion penetration are being studied in detail. The field has important applications in radiation damage, ion implantation, sputtering technology, electron microscopy, defect structures analysis and vacuum technology, many of which are basic to industrial processes. Modern advances have created a demand for education both from established scientists in Government and industrial laboratories and from new engineering and science graduates wishing to receive initial training. For the latter category over and above its intrinsic scientific value the subject involves a wide range of methods and techniques which make it an exceptionally valuable area for graduate training.’………….
…‘we offer a course beginning in October 1971, built upon a set of seven modules lasting about three weeks each. All of these could be taken individually by short term students whilst an approved selection of four, together with a project, will make a student eligible for an MSc award’…..
…..’while the majority of the tuition will be given by University staff we recognise that great expertise in this field resides in government and industrial research laboratories. We are therefore making extensive use of visiting professors from Harwell and invited speakers from industry.
In addition, the universities may permit an MSc student, in approved circumstances, to satisfy the project requirement by work carried out in an external organisation.’….
The course ran from 1971 to 1974. 33 MSc awards were made by Sussex University and a similar number by Salford. The Science Research Council provided some funding for approved students and this style of graduate course became a model that other universities followed.
Our DPhil students, as part of their initial course work, went through such modules as were appropriate to their research topic and some of the MSc students were offered the chance of continuing for the DPhil qualification. Even after the MSc course closed several of the modules continued for the DPhil coursework.
In appendix A we list all the Sussex staff members by category, academic, postdoctoral, technical and clerical; also the Salford academic staff, the visiting professors and the industrial collaborators who assisted in the supervision of Sussex students. This list includes those who were associated with the early course, and does not attempt to list the very many, and distinguished visitors who came to the group in later years.
In appendix B we list the Sussex graduate students with their years, the name of their supervisor and the title of their dissertation or thesis. This list is not confined to the initial years, but attempts to include everyone up to the 2010 when the accelerator group was finally closed. A summary of the initial employment from the early students and the current (2010) employment is noted where possible. We regret that the 2010 list is far from complete although many distinguished people are cited.
How well did the Particle-Solid Interactions Group perform the mission it began in 1965? Certainly it played its part in proving that the new University of Sussex would be able to support research at an internationally recognised level and to win research grants in competition with long-established universities. In 1961 in some influential circles this had been doubted. This account gives a snapshot of the work in progress in one research group in the mid to late 1970s. But it was but one of many groups of equal distinction flourishing in Sussex in that period.
It must not be thought from reading this history that the five academic staff devoted all their energies to research and postgraduate teaching. Each of them carried a full share of university duties that included undergraduate teaching, examining and administration. The proportion of each activity was different for each of them. Was the content of their undergraduate courses changed by this research? Rather little one suspects, because the research results were usually too detailed to include in the wider curriculum. But the quality of their teaching and its effect upon their students probably was enhanced. Amongst the many reasons are first, the depth of reading that one does to support personal research deepens ones understanding of Physics in concept and in technique and that makes one a better teacher of the general subject. Second, the experiences of research sharpen one’s mind to make it more critical of information received, whether from one’s own experiment or the account of someone else’s. When that critical approach is transferred through teaching Experimental Physics to undergraduates they will learn how to judge information for themselves, not only becoming better physicists but also better citizens.
In the early formative years of the group at least 50 graduate students were awarded higher degrees as a result of work they did in this group. In direct ways they were taught how to do research and they were given substantial knowledge. But they also learned for themselves and in graduating proved that they knew how to explore further and to make their own maps of knowledge. From the careers that can be tracked it seems likely that the individuals’ prospects were enhanced by the time the spent here and the people the met. That should be the proper outcome to education at any level. But in addition one might note the evident utility of the research and the outcomes for the benefit of institutions both public and private and the lives of people in general.
Undoubtedly the driving force of the initial implantation group was Professor Mike Thompson. Consequently the emphasis on the various topics changed somewhat when he moved into administrative posts at Sussex, and then left to become a Vice Chancellor of East Anglia and then on to Birmingham. His skill in these new tasks was recognised by a knighthood. Ion implantation however remained a key experimental focus for Drs Lucas, Palmer and Townsend and all three had a significant scientific output from the accelerator laboratory as well as their work in related areas of solid state and materials science.
The group of Professor Townsend built on their earlier techniques of optical effects of ion implantation and these were complemented by his laser, luminescence and thermoluminescence activities. There was considerable funding both from UK Research Councils, foreign industry and many European research programmes. Hence there were many effective collaborations and research visitors and students to the laboratory until its closure in 2010. A particularly key figure in the later years was Dr David Hole, who not only ran the 3MV machine, in close association with the experiments of Peter Townsend, but also had his own major programme with the JET laboratory on analysis of materials used in the development of Tokamaks. So, atomic energy was both at the beginning and at the end of the accelerator group’s research programme.
Monitors of success from the Townsend group included some 47 DPhil students and more than 20 MPhil and MSc degrees. Townsend was named the lead candidate for the Engineering section of the 2004 Descartes Prize on Excellence in Research for his work on improving photomultiplier tubes and their application for Optical Biopsy in breast cancer detection. In 2008 there was also a small celebration to note Townsend’s 500th publication. Subsequent Sussex publications from both Townsend and Hole are still emerging.
A working pattern of having visitors, both senior and postgraduate student level became firmly established and Sussex has benefitted considerably from this strategy. Many senior people have visited with funding from SERC, EPSRC, The Royal Society, EC funding, or other travel grants. Additionally the links have involved visiting students to Sussex, both at the graduate and undergraduate level. A complete chronological list of such visits is difficult to reconstruct as it involves several hundred people, many of whom have visited on many occasions. The following list therefore is intended to be indicative of the pattern and only cites a very few of the more long term collaborations. From the viewpoint of publications the same visitors are frequently co-authors together with members of their own research groups. This global pattern of research is highlighted by a brief head count of co-authors, and their countries, of Peter Townsend. In about 2008 he passed the 500 publication mark and at that stage had some 450 co-authors from 42 different countries.
Barry Farmery started a research programme with Dr Paul Coad at the JET lab in Culham. This was then expanded by Dr David Hole until the accelerator closure in 2010. The research has been key to assessing the problems of materials damage and transport within the Tokomak fusion reactor vessel in JET. The programme and our equipment has now moved to Portugal to continue work for ITER.
Peter Townsend had a very fruitful collaboration with Southampton and University College London with work on laser waveguides and photonics; a collaboration since 1974 with many member of the Universidad Autonoma de Madrid which generated some 50 publications, for which he received a Doctor Honoris Causa; Visits from Professor Bairui Yang and her students from Beijing have been particularly effective in terms of thermoluminescence publications and development of a new field of optical detection of phase transitions; a 6 year collaboration with Societa Italiana Vetro provided considerable accelerator funding, many papers and patents, and detailed studies of optical effects of ion implantation in glass. A number of EC funded programmes have advanced Condensed matter work from Sussex, and in particular, spectacular advances in the performance of photomultiplier tubes. In their use for breast cancer detection this resulted in the group leading the 2004 Engineering section of the prestigious Descartes prize. There was also a long term collaboration (~35 papers) with Prof Helen Rendell combining luminescence measurements with geological and thermoluminescence dating and analysis. This interest expanded to include several other partners from Madrid and St Andrews.
N M Khan Owns his own company. Surface Engineering, in UK.
Willy Siyanbola Leader of NACETEM Obafemi Awolowo University, Ile-Ife, Nigeria.
Harry Whitlow, Professor of Applied Materials, Lund University, Sweden and Jyvaskyla University, Finland.
The preceding is only a partial list and more details, updates, and addition of data for uncited students would be welcome.
This page was last edited on 7 January 2013, at 16:08.