I thank my associate investigators, other colleagues and collaborators for their advice in putting this proposal together. I also wish to acknowledge the Faculty of Science that provides substantial infrastructure support for this project (indeed our accelerator is one of the major assets of the Faculty). This allows me to request funds from the ARC that may seem modest in relation to the goals of the proposal by US, Japanese or European standards.

An extended version of this proposal which includes colour diagrams, appears at the web address: http://www.ph.unimelb.edu.au/~dnj/nano.html

We are in the era when fine probes (of electrons, tiny tips and photons) are being used to answer many important questions in modern materials science, technology and medicine. The arrival of nuclear microprobes opened a whole New World because of their unique ability to probe atom lattice location in crystals, map trace element distribution and image buried structures without specimen preparation. The other probes have now migrated into the sub-micron domain and there is a pressing need for the nuclear microprobe to take its proven capabilities across this frontier.

We aim to:

• Investigate, using powerful new insights, the use of magnetic quadrupole lens systems of advanced design to focus probes of MeV ions with sub-micrometre resolution.
• Build and test a sub-micrometre probe forming lens system incorporating the innovations described in this proposal.
• Apply the new probe to studies of frontier materials of great practical importance.

The significance of this work is that:

• Nuclear microprobe spatial resolution with practical beam current intensity for conventional Ion Beam Analysis has been stalled at about 1 micrometre for the past 20 years. Routine sub-micrometre probes would be a significant breakthrough because of the new problems that can be solved by exploiting the unique properties of MeV ions.
• It will confirm our preliminary work that the present theories in ion-optics do not adequately predict the behavior of high precision, strong focusing, magnetic quadrupole lens systems and allow more accurate theories to be developed.

The expected outcomes are that:

• We will construct a nuclear nanoprobe that crosses the present frontier of lens system performance.
• We will solve the practical problems set out in section 16 below listed under the heading "Applications for the new system".

This proposal combines several novel methods and established techniques. These are all very well documented in the literature and familiar not only to our own group but also to all the leading nuclear microprobe laboratories worldwide. Our main areas of innovation and advantage are our recent insights into advanced ion optics, the proposed novel probe forming

lens system, novel strong lenses and our existing high brightness accelerator. These are shown in Fig. 1.

In the beginning, probe design was largely guided by ion optics calculations adapted directly from theory applied to electron-optics. Modern computer codes fully exploit this theory. But over the past few years is has become increasingly clear that the theory has shortcomings for MeV probe forming lens systems. We have revisited the theory and made many careful experimental measurements and observations that show how the theory is inadequate. This has given us insights on how to break the sub-micrometre barrier. The research plan presented here represents a very brief overview of the complete proposal. Many more details including lens field maps, aberration calculations, figures of merit for a vast array of alternative lens configurations and engineering drawings are available. Our major insights are:

1. Our theory and measurements for magnetic quadrupole lenses for MeV ions reveal that the conventional theory appears to significantly overestimate that level of spherical aberration in quadrupole lenses. This means that the need to compromise the design of the probe forming lens system to minimise aberration is not necessary to the same extent as previously assumed. Our measurements, reasoning and conclusions about this important discovery have recently been published (G.R. Moloney, D.N. Jamieson and G.J.F. Legge, 1997).
2. Grid shadow patterns from the Melbourne nuclear microprobe system also appear to confirm this finding, although the result was originally attributed to parasitic octupole field components that, by an incredible coincidence, were assumed to cancel out a significant component of the spherical aberration (see D.N. Jamieson and G.J.F. Legge 1988), a conclusion we now believe is false due to point (1).
3. The other major aberration predicted by the conventional theory is chromatic aberration. But an Oxford high excitation triplet system operating with an unstable accelerator with no energy stabilisation system and without a high-dispersion energy analysing magnet, represents the state of the art of 300 nm and 100 pA of beam (F. Watt, 1997). Yet, by the conventional theory, the Oxford high excitation system is very sensitive to chromatic aberration! Furthermore, the grid shadow patterns for this type of system do not display the expected degree of fuzziness from chromatic aberration (unpublished measurements by David Jamieson, method fully described, with examples, in chapter 3 of M.B.H. Breese, D.N. Jamieson and P.J.C. King, 1996).
4. Ten years of work by our collaborators and us have shown that the best probe forming lens systems optimised for high demagnification incorporate one or more internal cross overs. However, the large demagnification, in theory, comes at the considerable cost of increased aberrations compared to systems without internal cross overs optimised for high demagnification. Points (1) to (3) above suggest that this is not as bad as previously assumed.
5. We have insights as to why the conventional theory may be inadequate for ion-optics and are working to rigorously formulate these insights.

Building on insight (1), we propose to go beyond the conventional systems and construct two variations of high excitation systems incorporating cross overs that have even higher demagnification than the Oxford system. As the result of our insights described here, we do not need to compromise the design to minimise the aberrations to the extent done in the past when the old theory was the only guide. By refinement of the theory, we plan to design and construct a probe forming lens system of unprecedented demagnification, and hence small probe size, incorporating:

• A novel magnetic quadrupole lens that incorporates a yoke of novel shape that offers many advantages over the traditional designs. The novel shape of the yoke allows us to construct a probe forming lens system with a very short working distance without compromising access to the specimen required for radiation detectors and optical microscopes. This design was recently published (see reference: C.G. Ryan et al, 1997).

• A novel arrangement of either 4 or 5 quadrupole lenses that can be specifically tuned to match to the characteristics of our accelerator. This will have a demagnification an order of magnitude larger than the present Melbourne system and are aiming for a spatial resolution of at least 100 nm with 100 pA of beam current.

• Our existing 5U Pelletron accelerator that we have shown to have one of the brightest beams of any accelerator worldwide used for nuclear microprobe operation. This machine would cost over $2M to replace, so we are exceptionally fortunate to have it available for this project. We published the comparison of our brightness with other machines in R. Szymanski and D.N. Jamieson, 1997.
• Twenty years of expertise in ion optics from the chief investigator and associates well known for their leading expertise in ion optics and nuclear microprobe applications.
• The activities of a large research group in Melbourne that is working with a large number of local and international collaborators on research projects that now demand improved spatial resolution over that presently available.

Each element is now discussed in more detail.

Novel magnetic quadrupole lenses: We propose to construct a new type of magnetic quadrupole lens that is specifically optimised for a high demagnification probe forming lens system. A schematic diagram appears in Fig. 2. The important ideas are:

1. Incorporation of pole extensions to cover the width occupied by the winding overhang, as this width is a significant fraction of the working distance of the probe forming lens system the demagnification is significantly increased as a result,
2. Incorporation of cutouts in the yoke of the lens to allow the radiation detectors and optical microscopes access to the specimen. Additional iron is allowed within the yoke to compensate for these cutouts,
3. The use of precision computer controlled wire cutting milling machines to cut the yokes from a single piece of iron to a machining tolerance of a few micrometres to ensure the minimum parasitic aberration,
4. The use of our sensitive lens aberration diagnosis technique, the grid shadow method, to measure the individual lens aberrations to detect invisible errors that would otherwise prevent sub-micrometre operation.
5. The use of the newly devised beam rocking technique (D.G. de Kerckhove et. al., 1997) for sensitive diagnosis of aberrations of the complete system.

Novel lens system design: With the novel lenses as described, we propose to test two highly optimised systems incorporating our key ideas. These are:

(1) The separated quadruplet designed by Glenn Moloney and described in full in his PhD thesis (G.R. Moloney, 1998)

(2) The separated quintuplet designed by Chris Ryan (C.G. Ryan and D.N. Jamieson, 1998)

These two systems are compared schematically in Fig. 3.

High brightness beam: The beam from our accelerator is highly heterogeneous, with the brightness in the paraxial regime being about 20 times higher that the average. The high brightness in the paraxial regime may be exploited by a probe forming lens system with a very large demagnification. This high brightness peaking is a general characteristic of electrostatic accelerators equipped with radio frequency or duoplasmatron ion sources, but the configuration of our machine is particularly favourable for this effect. As the most intense beam is in the paraxial regime, a probe forming lens system optimised for high demagnification is ideally matched to this machine.

Our laboratory is already well set up with an ion optical test bench to allow us to evaluate the performance of these two systems. The have been selected on the basis of ten years of work evaluating different configurations of quadrupole lenses for high resolution performance.

Once the new system has been constructed, we propose the following applications. These all require high resolution nuclear probes for further progress on solving important problems.

Applications of the new system: Many of the proposed applications for the new system build on the existing research projects of the MARC group at the University of Melbourne. This work is done in association with a large array of local and international collaborators and is funded separately to this proposal. This large collection of workers allows us to propose an ambitious research program for the new system. The most significant problems we plan to address are:

• Diamond and other wide band gap materials: Wide band gap materials have many potential applications to advanced microelectronic devices with desirable properties such as the ability to operate at high temperatures, in harsh radiation environments (D.R. Kania, et. al., 1993) or can produce strong electron emission for applications to flat panel displays. We have a substantial ongoing research program in diamond involving 4 academics and 5 PhD students and have applied for membership of the RD42 consortium for diamond detector development. The key problems we plan to investigate involving diamond are: synthesis and annealing; negative electron affinity; effect of grain boundaries on charge transport and recombination; trace element doping for the production of p-type and n-type materials; diamond heterojunctions with AlN and other compounds; laser annealing; carrier lifetimes. In each of these key problem areas, charge transport and recombination are key issues. These properties are determined by structures at the micron and sub-micron scale. Charge injection is difficult by conventional techniques in wide band-gap semiconductors, but the nuclear microprobe can easily promote charge across wide band gaps. It can also induce charge in buried junctions that are inaccessible to the electron probes. From our experience, the nuclear microprobe is ideal for this task and we have already widely applied it to related problems. However much of the structure in our specimens is below the present resolution of the nuclear microprobe, as grain sizes are generally no greater than 20 m m. Our recent publications show images where this structure is unresolved with the present system (see D.R. Beckman, et. al. 1997). Indeed, we observe considerable variations in charge transport characteristics within supposedly homogeneous grains. The proposed nuclear nanoprobe will be able to solve this problem. The research work in this area is done in collaboration with our Associate Investigator: Assoc. Prof. Steven Prawer.

• Geological minerals: Trace elements play an important role in geological minerals. They provide useful diagnostic information, often displaying large partition coefficients reflecting the original physical conditions or chemical processes present during the formation of the minerals. Trace nickel in garnet, measured using MeV particle induced x-ray emission, provides a direct measure of the equilibrium temperature at depth in the mantle for garnets entrained in erupting kimberlite magma. Trace zinc in chromite provides similar information. Combined with major compositional data, chromium in particular, the nickel geothermometer provides a means for fixing the depth of a garnet. The garnet chemistry can then be used to "image" the stratigraphy of rock lithology and chemical processes in the mantle to depths of about 250 km (see for example, W.L. Griffin and C.G. Ryan, 1995). However, trace elements in the mantle and crustal environments are often located in growth zones that are less than 10 micrometres in size. The proposed nuclear microprobe will be used to probe these zones for the trace element information. Our collaborative experiments have already demonstrated that new information can be obtained from the use of nuclear microprobe ion channeling analysis on geological crystals. We found trace gold substituted on the arsenic bearing pyrite crystal lattice in an epithermal gold ore system (reported in D.N. Jamieson and C.G. Ryan, 1995 and in J. den Besten et al. 1998). This allowed us to discriminate between several different models proposed for Au incorporation in the ore. Yet, growth zonation within mineral grains is often impossible to resolve with our existing system. Again, the proposed nuclear nanoprobe will solve the problem of measuring the composition of the individual growth zones. Our research work in this area is done in collaboration with our Associate Investigator Dr Chris Ryan.

• Living cells: Ionizing radiation has been shown to induce the death of mammalian cells and initiate mutagenic or carcinogenic changes (see G. Gerd, 1991). These issues are crucial in the use of non-sealed isotopes for cancer therapy, because the cellular localisation and radiation energy of the isotope employed can have dramatic effects on the efficacy of treatment. The ability to specifically target tumours while sparing normal tissues remains one of the most attractive new forms of therapy for cancer (see, for example, L. Larson, 1993). It is necessary to obtain more data to understand the basic principles underlying the effects of ion irradiation on living matter. For biological measurements with living materials, including cells in vitro, cells have to be irradiated while they are in their growth environment. This provides an experimental challenge that we propose to solve, a key element in which is the proposed nuclear nanoprobe. Sub-micron resolution is essential to be able to target sub-cellular structures. Our experiments will be carried out in collaboration with our Associate Investigator, Dr Marian Cholewa, who oversees the research program in this area.

Our methods and techniques have all been very well described in the literature and are too well known to need discussion in detail here. However, briefly, we propose to use:

• The quadrupole field mapping technique to evaluate the lens aberrations from a first principle calculation of the ray trajectories through the complete, experimentally measured field of a quadrupole lens of the type designed in the present proposal.
• The grid shadow method to diagnose the lens aberrations of individual lenses and systems of lenses (see chapter 3 of M.B.H. Breese, D.N. Jamieson and P.J.C. King, 1996, for full details).
• The computer controlled wire-cutting technique to cut the lenses from a single billet of specially heat-treated iron.
• The ion optics program PRAM for evaluation of the demagnification of the system constructed from the novel lenses and optimised to work with the brightness distribution of our high brightness accelerator. This program is described at length in chapter 3 of M.B.H. Breese, D.N. Jamieson and P.J.C. King, 1996.

All these techniques are areas where the present Chief Investigator has extensive experience.

1998: The design of the novel quadrupole lenses is essentially complete and a prototype is under construction. This will allow us to measure the strength of the novel design to ensure it is sufficient for a probe forming lens system as described here.

1999: The results from the prototype will be used to design the final configuration for the strong quadrupole lenses we plan to employ. It is envisaged that construction of the six lenses (one extra in case of random errors) will require most of the year and special magnet iron will be purchased for this purpose. At the same time, the final details of the probe forming lens system will be refined using the computer models.

2000: We commence evaluation of the individual lenses using the grid shadow method and verify performance and freedom from parasitic aberrations. In the first half of the year, we will assemble the lenses onto our existing beamline to test version (1) of the probe forming lens system and evaluate its performance. In the second half of the year we will rearrange the lenses and assemble version (2) to evaluate its performance using the grid shadow method and the beam rocking method.

2001: We will refine the final system intended for routine use in our laboratory and commence the projects described below to the selected frontier problems described above. At the same time, we will re-evaluate the ion optical theories in view of the experimental performance of the new system.

The present chief investigator has the following skills and expertise for the project:

• PhD work in ion optics leading to authorship of the main computer software used to evaluate the lens systems selected for this proposal.
• Inventor and expert practitioner of the grid shadow method applied to nuclear microprobe lens system to be used to evaluate the lens systems of this proposal.
• Extensive experience in the design of magnetic quadrupole lenses and lens systems.
• 12 years of experience in the use of nuclear microprobe systems to study advanced materials and solve practical problems.
• Invited keynote speaker at numerous local and international conferences over the past five years on the topic of this proposal.
• Guest research worker at several international institutions to perform research work on the topic of this proposal.
• Head of a large group of research students (7 under direct supervision, a total of 20 in the group) whose research work is the application of nuclear microprobes to the study of advanced materials as described above and whose work will benefit from the new nuclear nanoprobe of this proposal.

Role of Chief Investigator David Jamieson:

• To perform ion optics calculations using his ion optics computer codes: PRAM (Propagate Rays and Aberrations by Matrices), OXTRACE (for image simulations) for the design of optimum probe forming lens systems.
• To optimise the design of the probe forming lens system.
• To devise the optimum construction techniques for the lenses and the lens system.
• To integrate the new system with the existing Pelletron accelerator and test the lens system for sub-micrometre resolution.
• To supervise the applications of the new system to the analysis of advanced materials.

Role of the Associate Investigator Chris Ryan:

• To collaborate on the design of the individual lenses and the complete system of lenses in the five lens configuration with one cross over. Will provide access to advanced graphical visualisation tools used to study the effects of lens aberrations.
• To assist with testing of the prototype lens system by providing beam time on the HIAF accelerator in North Ryde.
• To provide geological specimens containing the sub-micrometre structures that will be analysed with the new system and to collaborate in the interpretation of the results.

Role of Associate Investigator Mark Breese:

• To collaborate on the design of the separated quadruplet incorporating two cross overs. In particular to evaluate the aberrations of the system using the existing ion optics computer codes.
• Provide access to his advanced lens system aberration measurement method based on beam rocking through large angles within the probe forming lens system. This method has shown exceptional sensitivity and readily applicable to our system. To initiate this work, Dr Breese visited our laboratory for three months in early 1998 under the University of Melbourne "Visiting Scholar Scheme" (competitive funding).

Role of Associate Investigator Marian Cholewa:

• To provide access to the biological specimens to be analysed with the new system.

Role of Associate Investigator Steven Prawer:

• To provide access to the diamond and other crystals that present the frontier problems that we can solve with the new system.
• To collaborate with DNJ on our part in the RD42 consortium aimed at bringing new technologies, such as diamond, to fruition as viable detectors for high energy physics experiments and other applications.

Role of proposed Australian Research Fellow:

The proposed ARF is to be the key partner in the present project. In 1997 and 1998 we specifically targeted several senior graduate students who are close to completion of their PhD studies at overseas universities as possible candidates for this position. The role for this fellow is:

• To provide a concerted effort of investigations with computer modelling using our ion optics computer codes and perform the theoretical work to incorporate the important modifications outlined here.
• To thoroughly explore the parameter space for the 4 and 5 lens systems proposed above.
• To perform the lengthy experimental work with the grid shadow method and the beam rocking method to evaluate the aberrations of the lenses themselves and then the lens system itself.
• To perform the nuclear microprobe analysis of the specimens selected for the high resolution studies in collaboration with the existing and future students who will have PhD projects directed at the study of a particular material for which the nuclear microprobe studies form a key part.
• The candidate we have in mind is presently completing her PhD on these topics.

Role of proposed Postgraduate Research Student:

• To learn the techniques of ion beam optics and take responsibility for aiding the ARF on the computer modelling for modifying the existing, inadequate, theory.
• To develop the analytical methods necessary to convert the experimental grid shadow patterns and beam rocking patterns into quantitative tools for lens aberration measurement.
• To simulate probe forming lens systems with chromatic and spherical aberrations taking full account of the insights listed in the research plan.

The track record of the Chief Investigator, David Jamieson, has been sufficient for him to rise from a level A lecturer through to level D reader in six years and become director of the Microanalytical Research Centre in 1996 against international competition. He has also:

• Had several industrial research contracts for the analysis of materials using the nuclear microprobe.
• Initiated the manufacture and sale of several significant nuclear microprobe components to laboratories in Europe and Japan.
• Been awarded one of the three inaugural Universitas 21 fellowships from the University of Melbourne in recognition of his teaching innovations and expertise.
• Been the keynote speaker at several international conferences over the past few years.

Australian Postdoctoral Fellowship: As stated above, this person is to be the key person in the proposal. We already have a candidate in mind for the position that is presently completing her PhD thesis on the topics of this proposal at an overseas institution. It is essential to have a person who can develop the necessary mathematical models to extend the present, inadequate, theories and incorporate the insights outlined here. It is also necessary to have a fellow who can apply this theoretical understanding to the difficult task of converting the theoretical abstractions in to real lenses of iron and copper. The candidate we have in mind will be ideal for these tasks and has already visited our laboratory where she provided a significant boost in our work on the diagnosis of lens aberrations.

Australian Postgraduate Scholarship: Some of the best experimentally oriented students narrowly miss out on research scholarships. We wish to have a scholarship available to tap this valuable resource.

Magnet construction materials: To date, many of our prototype lenses constructed on our quest for higher resolution probes has come from second-hand materials. We now need to purchase the highest quality materials available, in particular, high-grade magnet iron and high conductivity copper.

Precision computer controlled wire cutting and vacuum heat treatment: Wire cutting is the internationally recognised best method for precision machining of magnetic quadrupole lens yokes. We have been quoted commercial rates of $3000 per lens for the cutting process. We need to make at least 6 lenses to allow for one with random errors outside tolerances and a additional funds are required for the specialised vacuum furnace heat treatment required to make the magnet iron as magnetically soft as possible following a scheme we have devised.

Computer maintenance: For the ion optics calculations and quantitative analysis of the grid shadow and beam rocking patterns, intensive computations are required. Pro-rata, we request funds to maintain our existing system which includes a DEC Alpha for numerical simulations and an array of PCs for data acquisition, including CCD cameras for capture of the grid shadow patterns.

Machine maintenance: A standard sum is requested for maintenance of the accelerator and associated beam line for performing the ion optics experiments and analytical measurements for the duration of the project. The ARC is a vital source for essential maintenance funds for these facilities.

Magnetic shielding and laser splitting: Is required for installation of a magnetic shield on the nuclear microprobe beam line. Stray AC fields and inhomogeneous DC fields can easily degrade the resolution of the probe by a micrometre or more. To achieve routine sub-micrometre resolution, there is no choice but to shield the 8 m length of the beam line with a laser slit soft iron tube.

Calibrations standards: At the last nuclear microprobe technology and applications conference it was recognised that there was a need for a calibration standard for spatial resolution and a working group was established to produce such a standard by e-beam lithography. The standard will be used, when it becomes available, to test our new system.

Conference Travel: There is no question that many of the insights presented in this proposal we formulated in consultations with peers at numerous conferences and workshops over the past 8 years. We wish to continue this tradition, as well as present the results of this work at the nuclear microprobe technology and applications conference series (ICNMTA7 2000 in Europe) and the Materials Research Society conference in Boston 1999 and the Ion Beam Analysis Conference, probably in the USA, in 2001. We ask only for a fraction of the total cost of attending the designated conferences, but conference travel is not possible without this vital ARC support.

D.R. Beckman, A. Saint, P. Gonon, D.N. Jamieson, S. Prawer and R. Kalish, 1997, Nucl. Instr. Meth in Phys. Res. B130 (1997) 518.

M.B.H. Breese, D.N. Jamieson and P.J.C. King, Materials Analysis with a Nuclear Microprobe, J. Wiley and Sons, New York, 1996.

J. den Besten, D.N. Jamieson and C.G. Ryan, 1998, to be go to the J. Appl. Phys. (1998).

D.G. de Kerckhove, M.B.H. Breese and G.W.Grime, Nucl. Instr. Meth. In Phys. Rtes. B129 (1997) 534.

G. Gerd, 1991, Nucl. Instr. Meth in Phys. Res. B54 (1991) 411.

W.L. Griffin and C.G. Ryan, 1995, in Diamond Exploration, ed. W.L. Griffin, J. Geochem. Explor. Spec. Vol 53 (1995) 311.

D.N. Jamieson and C.G. Ryan, 1993, Nucl. Instr. Meth in Phys. Res. B77 (1993) 415.

D.N. Jamieson and G.J.F. Legge, 1988, Nucl. Instr. Met. In Phys. Res. B34 (1988) 411.

D.R. Kania, M.I. Landstrass, M.A. Plano, L.S. Pan and S. Han, 1993, Diamond and Related materials, 2 (1993) 1012.

L. Larson, 1993, Acta Oncologica 32 (7/8) (1993) 709.

G.R. Moloney, 1998, PhD thesis, unpublished (much of the content of this thesis is already available in the publications of Moloney, Jamieson and Legge as listed in the publication list of David Jamieson in section 21 of this proposal) or, more conveniently, from the Glenn Moloney web site: http://www.ph.unimelb.edu.au/~glenn

G.R. Moloney, D.N. Jamieson and G.J.F. Legge, 1997, Nucl. Instr. Meth. In Phys. Res., B130 (1997) 97.

C.G. Ryan, D.N. Jamieson, W.L. Griffin, S.H. Sie, G. Cripps and G.F. Suter, 1997, proc. 10^th Australain Conf. on Nuclear Techniques of Analysis, Canberra, 1997, ISSN 1325-1694 1997.

C.G. Ryan and D.N. Jamieson, 1998, to be presented at the Sixth International Conference on Nuclear Microprobe Technology and Applications, Cape Town, South Africa, October 1998 and to be submitted for publication in Nucl. Instr. Meth. In Phys. Res. B.

R. Szymanski and D.N. Jamieson, 1997, Nucl. Instr. Meth. In Phys. Res. B130 (1997) 80.

F. Watt, 1997, Nucl. Instr. Meth. In Phys. Res. B130 (1997) 1.