Research-PSI

Particle-Solid Interactions

Draft 31/10/2010

A History of the Particle-Solid Interactions Research Group
in the School of Mathematical and Physical Sciences
at Sussex University

Origins

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 University of 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 only increased in size to the point where almost 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.

Themes

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.

Scientific Interests

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 get 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 is 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. 50keV Ar+ ions bombarding a sample of copper will produce the same sort of atomic recoils in as 2MeV 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.
(I hope John could amend or add some more here, especially microstructures from ion bombardment and electron damage)

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 + E_b)³ for the energy distribution and this was being found in many experiments ( E_b 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 if 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 semiconductor crystals and in certain oxide crystals but he also studied niobium with oxygen dissolved in it. The former had great practical importance in electronic devices and the latter were valuable in studying the phenomenon of ion channelling. He had shown that ionisation by a fast (MeV) light ion could damage the structure in silicon additional to the damage it did by creating collision cascades. He showed how to use channelling of MeV ions as an analytical tool to detect defects created by radiation damage or ion implantation, analyse their structure. Then he followed changes in their structure caused by heating and related the changes to bulk properties. These were important experiments as the technology of semiconductor devices was being developed and amongst his industrial collaborators were staff of the Phillips Laboratories at Redhill.

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.
(are we in touch with Derek and might he amend and perhaps add something?)

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’.
(is Mike able to add something here?)

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 (eg. 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 he 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).

Postgraduate Teaching

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 is 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.

In the latter our group developed an MSc course jointly with a group having similar interests at Salford University. It was entitled ‘Atomic Collisions in Solids’ and was described in its prospectus as follows:-

‘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 titles of the modules were:-

1. Theory of the defect solid state and atomic collision processes
2. Radiation damage
3. Structural analysis of crystals
4. Ion implantation
5. Ion beam technology
6. Composition analysis of solids
7. High vacuum and high voltage technology

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.

In appendix B we list all of the Sussex graduate students with their years, the name of their supervisor and the title of their dissertation or thesis. It may also be of interest to note the subsequent employment of our students after graduating and where we have the information this is included.

Conclusion

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.

Postscript

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 ( dates) and then on to Birmingham (…). His skill in these new tasks was recognised by a knighthood in ????. 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.
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 44 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.

Should there be more in this section from Mike Lucas and Derek Palmer?

MWT+ PDT

APPENDIX A

Staff (we probably need some more in and out dates for the Sussex team)

University of Sussex University of Salford (collaboration 1971-75)

Professor M W Thompson, Prof. of Experimental Physics, (1965-80) Professor G Carter, Prof. of Physical Electronics
Dr M W Lucas, Lecturer in Physics (1966--- ) ? D G Armour, Lecturer in Electrical Engineering
Dr D W Palmer ,, (1966- --) ? Dr J S Colligon ,,
Dr P D Townsend ,, (1966---) ? Dr W A Grant ,,
Dr J A Venables ,, (1963- ) ? Dr F Paton ,,
Professor R W Cahn, Prof of Materials Science (1963-80) Dr R Andrews ,,
Dr G Farrell ,,
Professor G Dearnaley, Visiting Professor, AERE Harwell Dr G A Stephens ,,
Professor R S Nelson ,, ,,
Dr B L Eyre, External supervisor, AERE Harwell
Dr A E Hughes, ,, ,,
Dr M J Makin, ,, ,,
Dr P Blood ,, Phillips Research Labs.
Dr J Shannon ,, ,,
(a few more here I think)

R A R Bayly, Research Fellow in Physics (1970-73) ?
Dr P Combasson ,, (1976)
Dr K H Ecker ,, (1971-73)
Dr L Holland ,, (1974-75)
Prof J C Kelly (senior visiting) ,, (1967 & 1974)
Dr J O’Connor ,, (1979-81)
Dr H J Pabst ,, (1973-76)
Dr A P Pathak ,,
Dr M Saidoh ,, (1975-76)
Dr D van Vliet ,, (1967-70)
Dr W Steckelmacher ,, (1974- ) ?
Dr T R Wilshaw, Research Fellow in Materials Science ( 1968-71)
Dr I H Wilson, Research Fellow in Physics (1965-68)
(and here)

Mr B W Farmery, Experimental Officer in Physics
Mr E Turpin, Technician
Mr N Priestley ,,
Mr D Hole ,,
Mr A Houghton ,,
Miss J Teare ,,

Miss N Kingan Secretary (1965-69)
Mrs M Tait ,, (1969 – 8?)

APPENDIX B

Postgraduate Students

Name Degree Dates Supervisor Title of Thesis

A D Marwick DPhil 1966-70 M W Thompson Channelling and Surface Scattering

C Foster DPhil 1966-70 I H Wilson Atomic Scattering and Interatomic Potentials
M W Thompson

Z Sumengen MSc 1966-67 D W Palmer Channel Electron Multipliers as Detectors of Electrons and Protons

G Chapman DPhil 1967-71 M W Thompson High Energy Sputtering

B Stocking MSc 1967-8 M W Lucas Measurement of the Surface Density of Thin Foils

M Kidd MSc 1967-8 M W Thompson Topography of Sputtered Surfaces

D Richards MSc 1968-69 P D Townsend Sputtering Measurements of Silica and Sodium Chloride

T G Williams DPhil 1968-71 D W Palmer Ion Channelling and Irradiation Effects in Gallium Arsenide

D J Elliot DPhil 1968-71 P D Townsend Low Energy Ion Irradiation in Alkali Halide Crystals

N E W Hartley DPhil 1968-71 R W Cahn & T R Wilshaw The Comminution of Minerals, some Fracture and Deformation Studies on Quartz with reference to Size Reduction

G S Harbinson DPhil 1969-73 M W Thompson X-Ray Production and Ion Scattering from Surfaces

P J Mac Donald DPhil 1969-73 D W Palmer Ion Implantation in Germanium

G C Crittenden DPhil 1969- 73 P D Townsend Thermoluminescence in Doped LiF

R Browning MSc 1969-70 P D Townsend Defect Formation in Alkali Halides
                 DPhil 1971-74  Sputtering Patterns from Electron Irradiated Alkali Halides

K G Harrison DPhil 1969-71 M W Lucas Beam Foil Electron Spectroscopy

H J Pabst DPhil 1969-73 D W Palmer A Channelling Study of Defects in Silicon

A H G El Dhaher MSc 1969-70 D W Palmer A 60 kV Accelerator System for Low Energy Channelling Studies

N M Khan DPhil 1970-74 M W Lucas Charge Exchange to the Continuum in Single Crystals

T C Ang MSc 1970-71 P D Townsend & A R Bayley Colour Centres in Silica induced by Ion  Implantation

Y Al Jammal MSc 1971-72 P D Townsend Electron Produced Sputtering of Alkali Halides
DPhil 1972-75?

T F Bartley MSc 1971-72 M W Lucas Measurement of Equilibrium Charge-Fraction Ratios of H⁺ , H^₂+ and H^₃+ Ions in Carbon Using Continuous Channel Electron Multipliers

D Bean MSc 1971-72 L Holland The Cleaning of Silicate Glass Surfaces in a Radiofrequency Discharge

J P Davies MSc 1971-2 D W Palmer An Investigation of the Channelography Technique

G G W Durbin MSc 1971-72 J A Venables Low Temperature Observations of Li and Na in the Scanning Electron Microscope

J M Gilkes MSc 1971-72 P D Townsend Spectral Investigation of the Thermoluminescent process in LiF

G W Nielsen MSc 1971-72 M W Thompson Rutherford Scattering from Metals
                   DPhil 1972-76  A Rutherford Backscattering Study of Heavy Ion Ranges in Polycrystalline Aluminium and Amorphous Silicon

R R Armstrong MSc 1972-73 D W Palmer Channelography of Thin Metal Foils

P Barlow MSc 1972-73 M J Makin Irradiation Damage Studied by High Voltage
              DPhil 1973-75 J A Venables Electron Microscope

P Chandler MSc 1972-73 R S Nelson & P D Townsend Surface Studies Using Ion Bombardment

J D Lee MSc 1972-73 A E Hughes & P D Townsend Radiation Damage in Electrical and Optical   Components

B T Meggitt MSc 1972-73 M W Lucas Charge States of Hydrogen Atoms Traversing Foils

I I Sheikh MSc 1972-73 P D Townsend Thermoluminescence Defect Studies in Lithium Fluoride

J P Summers MSc 1972-73 B L Eyre & J A Venables Electron Microscope Studies of Self-Ion Damage in Copper

R E J Watkins MSc 1972-73 G Dearnaley & M W Thompson Radiation Enhanced Diffusion in Metals

P Barker MSc 1973-74 D W Palmer Proton Irradiation of Germanium

S Datta MSc 1973-74 A E Hughes & P D Townsend Luminescence Dosimetry using LiF

S E Donelly MSc 1973-74 R S Nelson Diffusion of Inert gases in Metals

D W Garlant MSc 1973-74 P D Townsend Luminescence During the Sputtering of Alkali Halides

J W Muncie MSc 1973-74 B L Eyre & J A Venables Proton Damage in Metals Studied by Electron Microscopy

R Bin Jaya MSc 1974-75 J A Venables Use of the Scanning Microscope to Obtain Crystallographic Information

M Brown MSc 1974-75 D W Palmer & H J Pabst Computer Simulation Calculation of Proton Damage in Silicon

A Majoubi MSc 1974-75 P D Townsend Sputtering of Alkali Halides

A Nyaiesh MSc 1974-75 M W Lucas Stopping Power for Protons and Molecular Hydrogen Ions

P Goode MSc (part time) 1972-75 G Dearnaley Study of the Effects of Ion Implantation on the Thermal Oxidation of Nickel

R W Cranage DPhil 1972-75 M W Lucas Absolute Cross sections for Charge Exchange to the Continuum

I Reid DPhil 1971-76 M W Thompson Sputtering Processes in Gold

S D Mukherjee DPhil 1973-76 D W Palmer A Study of Proton Channelling and Dechanneling in MgO

A P Webb DPhil 1973-76 P D Townsend Refractive Index Changes Produced in Silica by Ion Implantation

B Cephalas MSc 1976-77 P D Townsend Temperature Effect on Refractive Index Changes Formed by Ion Implantation

M Wintersgill DPhil 1974-77 P D Townsend Luminescence in LiF: Mg: Ti

R Strong DPhil 1974-77 M W Lucas Electron Loss From Light Ions

R E Kaim DPhil !974-77 D W Palmer Oxygen Locations and Oxygen-Defect Interactions in Ion Irradiated Niobium

P J Chandler DPhil 1974-77 P D Townsend Radiation Induced Fluorescence in Insulators

P Barker DPhil 1975-78 D W Palmer A Study of Proton- Irradiation Damage of Germanium

S Ahmad D Phil 1976-80 M W Thompson Effect of Ion Mass on the Energy Spectra of Sputtered Gold Atoms

H J Whitlow DPhil 1977-80 M W Thompson & D J O’Connor Low Energy Ion Implantation of Silicon

Peter – this is as far as my records go. Can you find the rest?

First Known Destinations or Employers of Graduate Students (1965-75)

Adam Hilger Scientific Publishing
AERE Harwell
Bell and Howell Ltd
Birmingham University
British Cellophane Ltd

ESSO Research Labs UK
FOM Research Institute, Amsterdam, Netherlands

Gillette Research Labs UK
Hospital Physics Dept at St Luke’s Hospital Guildford
Imperial College London
Kent University
National Radiological Protection Board
National Westminster Bank
Research Labs of Gillette Industries
Riverina College, NSW, Australia
Salford University
Surrey University
Sussex University
UKAEA Dounreay,
University of Islamabad, Pakistan
Voluntary Service Overseas
Warwick University
York University

5 Students went to positions in industry from this Sussex MSc
10 students went on from the Sussex MSc to a Sussex DPhil and
7 to PhDs elsewhere
2 went from this Sussex DPhil to postdoctoral positions at another university (Ahmed, Browning + ?)

Posts held by Alumni in 2010 (where known)

Shoaib Ahmed, Board member Pakistan Atomic Energy Agency
Harry Whitlow, Professor of Applied Materials, Lund University, Sweden and Jyvaskyla University, Finland.
Alan Marwick, consultant in computer systems in New York after retiring from senior positions with IBM
Peter, lots more to add here I think