The Australian Synchrotron - a Progress Report

AU0524251 The Australian Synchrotron - A Progress Report

J BOLDEMAN1, A JACKSON", G SEABORNE", R. HOBBS' and R GARRETTb "Australian Synchrotron Project, Level 17, 80 Collins St, Melbourne "Ansto, PMB1, Menai, NSW

Abstract. This paper summarises progress with the development of the Australian Synchrotron. The potential suite of beamline and instrument stations is discussed and some examples are given.

1. The Australian Synchrotron Project and completed in 1998 [2] recommended that a Synchrotron radiation is emitted when electrons, compact mid energy facility similar to that for example, travelling with velocities close to the proposed for Canada [3] and one in the planning speed of light are bent in a magnetic or electrostatic stage for the Stanford Linear Accelerator field. The electromagnetic radiation so released, Laboratory [4] would be an ideal choice. Thus the tangential to the electron path, is enormously more recommended energy for the facility was 3 GeV. intense than that from laboratory X-ray sources, the The facility would also need to be equipped with at radiation is emitted in a broad energy spectrum and least 9 different beamlines in Phase I to satisfy the specific energies or wavelengths can be selected for design objectives. experimental applications. The radiation is also emitted with a very small divergence with respect 2. The Boomerang Storage Ring to the plane of the electron beam. Synchrotron The Australian Synchrotron is being constructed by radiation has become a key analytical tool with the Victorian Government on a site adjacent to wide scale applications in the materials and Monash University in Melbourne. The facility is chemical sciences, molecular environmental based on the Boomerang Storage Ring which has a science, the geosciences, nascent technology and DBA structure (Figure 1) with 14 superperiods. defence related research among many fields. As a Each cell comprises two dipoles (D), six consequence, more than 80 international quadrupoles (Q) and seven sextupoles (S) separated synchrotron facilities are either in operation or by appropriate drift spaces. The dipoles have planned. An evaluation in 1999 [1] indicated that modest gradient fields to provide set horizontal after several years of operation, an Australian based defocussing. Initially, the lattice was planned to facility would have an Australian user community have 12 fold symmetry with a circumference of of approximately 1200 different researchers and a approximately 184 - 189 m [5]. However possible international cliental of 350. In response consideration started to be given to a larger lattice to this opportunity for outstanding wealth and finally it was decided that the best performance generation, the Victorian Government has versus cost option for an Australian based facility committed $157 M towards the construction of a would be to have 14 periods for the lattice with a national synchrotron facility. The total cost in circumference of 216 m [6]. This allowed two Phase I including beamlines and experimental additional straight sections for insertion device stations is $206M. The design objectives for the based beamline facilities and also reduced the Australian synchrotron were to satisfy the research emittance by approximately 35%. The key requirements of 95% of Australian user needs and parameters are listed in Table 1. The design to satisfy all of those of Australian industry. objective was to achieve a low emittance in a Naturally, the facility needed to be of world class relatively compact circumference that had an but had to fit within the budget that might be excellent dynamic aperture and was robust with expected for an Australian facility. A Feasibility respect to potential construction aberrations. Study commissioned by the Federal Government

Table 1 Basic Properties of the Lattice

n=o r|= 0.24 m Energy 3.0 GeV 3.0 GeV Circumference 216m 216m Periodicity/ Usable straights 14,12 14, 12 Betatron Tune - H,V 13.30,5.2 13.30,5.2 Current 200 mA 200 mA Radiation Loss/turn 932.2 keV 932.2 keV Nat.Emittance 15.81 nm rad 6.98 nm rad Beam Magnet Field/ Critical Energy 1.301 T,7.8keV 1.301 T,7.8keV Critical Energy 7.8 keV 7.8 keV Hor. Beam Straight, Vertical Beam Size 389 microns, 20.5 microns 340 microns, 12.7 microns

22 A full energy injector based on a linear accelerator discussed in [7]. The straight sections from magnet feeding a booster synchrotron (130.2 m with an surface to magnet surface are quite long at almost emittance < 100 nmrad) will be installed. 5.4 m allowing long insertion devices of up to 4.6 Questions of stay clear and apertures have been m in length.

FIGURE 1 One Superperiod of the Boomerang Lattice, D - light background dipoles, Q - dark background quadrupoles and S - semi-dark background sextupoles.

3. Beamline Facilities • Microbeam Applications 14% The strategy for the new Australian Synchrotron is • Materials Research 21% to cater for the requirements of 95% of the research • Biotechnology 14% interests of the Australian community. The size of • X-ray Physics 12% the community has increased over the last 10 years • Minerals and Mining 12% principally through the auspices of the Australian Synchrotron Research Program and the current • Polymers /Soft X-rays 9% community numbers more than 300. Demographic • Chemical Sciences 9% projections based on international experience • IT Applications 6% suggest that the Australian based research • Environmental Science 3% community in the mature period (after 5 years of Ultimately, the facility will attempt to cater for all operation) should be approximately 1200. The of these applications and prospective new present activities of this community according to opportunities as they arrive. The Australian research areas (based on ASRP data) is as follows: community has been invited to propose a set of beamline and instrument stations for Phase I of the operation. These are listed in Table 2.

Table 2 Beamline Proposals Beamline Description Source Energy Range Protein Crystallography (MAD) bending magnet 2 - 20 keV Protein Crystallography (MAD) and SmalMoleculesl 22 mm undulator 5.5 - 20 keV Microfocus 22 mm undulator 5.5-25keV Powder X-ray Diffraction bending magnet (wiggler) 4 - 60 keV X-ray Absorption Spectroscopy (XAS) wiggler 4 - 65 keV X-ray Imaging wiggler 4 - 85 keV Small and Wide Angle X-ray Scattering (SAXS, WAXS) 22 mm undulator 5.5 - 35 keV Visible Ultra Violet (VUV) 185 mm undulator 10-350eV Soft X-ray 55 mm undulator 200 - 3000 eV Vibrational and Optical Spectroscopy bending magnet 0.001 - 1 eV General Purpose Microprobe bending magnet 4 - 35 keV LIGA bending magnet 2 - 25 keV Circular Dichroism undulator 2-100eV

23 Funding is being sought for as many of these soft X-rays a 55 mm period out of vacuum proposals as possible. Design of these beamlines is undulator is an obvious candidate. Figure 2 and 3 proceeding and it is hoped to have as many presents the brightness that would be achieved from operational on day 1 as possible. It is clear from the the lattice operated in its minimum emittance mode Table that high brightness/flux on target is required for both of these IDs respectively [4]. The in the 10-20 keV range which of course was the calculations presented in the figures include the principal argument for the 3 GeV ring. To provide impact of the beam energy spread but not potential competitive performance in this region a 22 mm in magnet errors. vacuum undulator is under consideration. For the

Boomerang 22 mm Unrtuhittir Koomcrang 55 mm Umlulatwr

1.0EJ8';

1.0F.I7 j-

I.DE1S i. 2 3 Fnci-gr (kcYi FIGURE 2 Brightness plots for the 22 mm Undulator FIGURE 3 Brightness plots for 55 mm Undulator

Figure 2 showing harmonics to 9 indicates that the performance of Insertion Devices and by the there is excellent brightness to at least 20 keV. The time a decision is needed on appropriate IDs there brightness for harmonics 1 to 5 is shown in Figure may be new opportunities. 3. The photon flux that is achievable on the Boomerang bending magnets is shown in Figure 4 Comments on the various beamline proposals are and that for a high performance wiggler (61 mm presented below. The maximum beamline length period, K= 10.8) is shown in Figure 5. hi recent (to the target) that can be considered within the times, considerable advances have been made in confines of the synchrotron building is 40 m.

LDE14 I.0EK

•

.-. 1.UE13

• 1 \ S .L0E12 - I \ C 1.0E11

1.UE1O l.OEli 1.0K2 1.0E3 1.I1E4 L.0E3- Photuii Energy (e\"l

FIGURE 4 Flux from Bending Magnet FIGURE 5 Flux from 61 mm Wiggler

24 3.1 Protein Crystallography Two beamlines are planned for protein Macromolecular or protein crystallography (PX) is a crystallography as part of a comprehensive program method for determining the structures of large in this vital area of research. One of these will be a biological molecules, specifically proteins and conventional bcamline sited on a bending magnet that Protein Crystallography is recognised internationally will cater for high throughput studies, exploratory as one of most important applications (if not the most studies and rapid response activities. The second will important) of synchrotron facilities. The Intellectual be based on a 22 mm in vacuum undulator providing Property generated in this science is the basis on microfocus beems probably to an instrument station which many modem dnigs are developed. It also at 38.5 m. Without defining slits it is hoped to focus provides critical information on life science the beam to 100 urn horizontally and 50 (im within a processes. As a consequence all major OECD total divergence of 0.2 mrad. For smaller crystals nations have invested heavily in synchrotron slits will be required to reduce the beam size. This st facilities. At the 1 October this year, 22,700 protein beamline will also cater for the small molecule structures had been deposited in the Protein Data community. Both beamlines will be multi-wave Bank of which 19,285 had been determined by X-ray anomalous dispersion (MAD) capable. It is also Diffraction. planned to use robotics and to be capable for remote operation. A possible design is shown in Figure 6.

FIGURE 6 High Resolution Protein Crystallography Bcamline

The micro-focus protein crystallography beamline (10-30 micron size, which are, in general, will deliver a competitive 1.6 * 10 ' photons per difficult to grow and diffract weakly) can be second into a 100 x 50 micron spot size with a total studied. Also, data from large protein complexes divergence of 0.2 millirads at the Se edge with a and virus crystals, as well as ultra high (atomic) bandwidth of 0.1%. For the bending magnet resolution data can be collected. beamline which would have a greater beam • Multi-wavelength technique: Multiple divergence the flux is not greatly lower. The Anomalous Dispersion (MAD) is one of the experiments performed at the facilities for most rapid methods of determining the structure macromolecular crystallography at third generation of biological macromolecules. It requires highly sources include: collimated, variable-wavelength X-rays. This • Monochromatic crystallography: Utilising high technique is expected to be performed on less flux and brilliance, improved collimation, and demanding, highly diffracting crystals. the fact that the experimenter can choose the Special Experiments: Some special experiments can energy of the input photons. High brilliance is include the Lane diffraction or white-beam (or pink- important for measuring diffraction data of beam) method. In this case, the macromolecular extremely small and weakly diffracting crystals. crystal is exposed to a wide range of X-ray energies, Micro-crystals of proteins and small molecules

25 3.2 Microfocus Beamline Geoscience. Micron resolution is essential in the Australian use of international synchrotron facilities earth sciences in order to deal with typical natural has been characterised by an unusually high sample sizes. The major analytical techniques such as proportion of use of microprobe facilities. At other electron probe, laser ablation ICPMS and ion probes institutions in Australia there are two proton like PIXE and SHRIMP have micron-scale microprobes and one heavy ion microprobe. This resolution. The ability to produce an element map a focus on microprobes results from the importance of sample and to determine the oxidation state as well mineral exploration and extraction to the Australian on how a particular element is bound or coordinated Australian use of international synchrotron facilities is the scientific 'quantum leap' offered by the has been characterised by an unusually high synchrotron microprobe over all other microprobe institutions in Australia there are two proton techniques. It leads in particular to microprobes and one heavy ion microprobe. This • Increased efficiency of mineral processing focus on microprobes results from the importance of • More efficient management of mine wastes mineral exploration and extraction to the Australian and mining operations economy. The requirements for this beamline • A better understanding of ore forming include the capability of focussing the X-ray beam at processes can be used in predictive the target to spot sizes as small as 0.2 urn, beam exploration. energies to 20 keV and of course the highest flux that • Improve understanding of the geological can be obtained from the facility with these conditions leading to the release of S. specifications. • Tiny inclusions of melt trapped in zircon The microfocus beamline finds applications in an crystals > 4 billion years old can be analysed extremely wide variety of scientific and technical for chemical indicators of the hydrosphere areas including and atmosphere at that time. Biotechnology. Simultaneous elemental and chemical mapping of tissues, cells etc provides • A better understanding of diseases, immune Materials. Ion microprobes are used in many areas processes as well as toxin and heavy metal of Materials research, which can be enhanced by uptake of tissues down to a sub-micron synchrotron microprobes to take advantage of the cellular level as well as the functionality of a lower sample damage rate of x-rays compared to ions large number of metalo-proteins. and trie ability to obtain physical and chemical • The mapping of the distribution and information such as biotransformations of anti-cancer and other • surface corrosion, micro-pitting and wear drugs in cultured cells and tissues for mechanisms of materials improved drug design and delivery. • a better understanding of the chemistry and • Two-dimensional scanning of interaction processes of impurities and chromatography gels in which all of the contaminants in materials proteins of an organism or an organ are • debonding and delamination processes, separated will enable all of the particularly related to composite materials metalloenzymes to be mapped, especially on on a micro scale those containing Se and S. • polymer crystallisation and seeding of polymers • A better understanding of the distribution, for industry to produce consistent quality uptake and metabolism of metal-containing and reduce refuse pharmaceutics in cells and tissue for the • grain boundaries, impurities, charge transport development of better and safer drugs. XAS and collection efficiency, lifetime, on a sub-micron scale can provide structural recombination, band gap in photovoltaic chemical information regarding the materials to improve efficiency in photovoltaic intracellular biotransformation of the drugs. materials • A range of different metal oxides can be • a better understanding of the structure, porosity, attached to different sequences of DNA or composition of fuel cell electrodes as well as RNA sequences and scanned by a nanoprobe their poisoning, impurity distribution and to obtain gene maps. oxidation to improve the performance and Environment. Increasingly the study of toxins in the durability of fuel cells. environment and their pathways requires submicron resolution as well as the ability to determine their oxidation state.

26 3.3 Powder Diffraction • In situ measursiments of reaction kinetics and structural changes. For example, temperature Australian science has had a long history at the pressure dependent dehydration mechanisms, forefront of powder diffraction studies with neutrons porous materials (zeolite-like materials) and as well as X-rays. Experiments performed on the temperature and pressure dependent phase Powder X-ray diffraction beamline diflractometer transitions (including changes of symmetry, will be directed mainly towards determining the and superlattice reflections) atomic structures of powdered crystalline samples. Such studies fall into the following broad classes: • Pair distribution function analysis of disordered materials including superconducting cuprates, • Structural properties relations in transition metal semicrystalline polymers and nanocrystalline oxides particles • Accurate inorganic structures of materials for • DisoredereJ and defect structures. technical applications like superconductors, functional materials and porous materials A possible configuration of the beamline is shown in Figure 7.

Figure 7 Powder Diffraction Beamline

3.4 X-ray Absorption Spectroscopy provide important new insights into metal-based Approximately 25 % of all use of synchrotron toxicology. facilities by Australian scientists involves application • Anti Cancer Drugs. Extensive XAS investigations of XAS techniques. Some applications include of Co and Pt anti-cancer drugs are in progress with Biochemical Sciences the aim of developing new technologies that enable • Carcinogens. XAS is being utilised for the first the determination of the oxidation state in-situ in time to characterise the structures of a range of different regions of tumours and in models of reactive Cr(VT), Cr(V) and Cr(lV) complexes with hypoxic tumours. This will enable the rational tuning biological reductants. Many Cr(III) complexes, of the reduction potentials to achieve on the which are the ultimate products of the reductions relationship between reduction potential and the have also been characterised. This research will extent of activation in hypoxic environments.

27 • Veterinary drugs. Co, Cu, Ni and Zn anti- inflammatory drugs are potent veterinary drugs and are likely to enter human clinical trials in the near future. XAS has been used extensively in the Physical Sciences and Engineering characterisation of new drugs in the solid state, • Experimental and theoretical investigations solution, pharmaceutical formulations and biological have been combined to produce absolute XAS fluids. This research has been essential in measurements to enable new critical tests of determining the stability of the drugs in relativistic atomic, molecular and solid-state dogma. pharmaceutical preparations and in understanding the This program has provided calibration on two new pharmacology. axes previously unavailable for either experimental Chemical Sciences or theoretical studies. D-block elements. XAS studies are in progress to • Micro- and meso-porous materials, such as better understand the influence of redox or charge zeolites and their analogues, are of major importance state on the electronic and molecular structure of as the substrates for catalysis - chiefly to prepare fine metal complexes or clusters so as to better anticipate chemicals, crack heavy hydrocarbons, adsorption- (and ultimately control) the reactions and reactivity separation and polymer synthesis. The micro/meso- of transition metal catalysts. The metal clusters that porous structure of such materials can be doped with lie at the active site of the nitrogenase and metals like Mn, Mg, Cu, Zn, Ni and Co to hydrogenase enzymes provide challenging, but incorporate metals in the framework and generate important, target molecules for this work. Techniques microscopic centres for catalysis. XAS experiments have been developed to permit in-situ spectroscopic yield atom-specific information of the absorber examination of reactive electro-generated species environment useful for designing and developing including the use of IR and UV-Vis spectroscopies efficient catalytic systems. to complement direct structural characterisation with XAS. New Science Initiatives Earth Sciences • Nanoscience • XAS is being used to identify the metal • Ultra-Dilute Measurements complexes involved in the transport of ore-metals • Fast-Scanning/Time-Resolved Measurements (Cu, Au, Ag) by supercritical hydrothermal solutions to form economically important ore-deposits 3.5 X-ray Imaging • The oxidation state of elements in magmas Phase contrast imaging is an area of research that has (silicate melts) is being determined with XAS. The also had considerable activity in Australia. It is abundance of elements in the mantle relative to proposed to combine this activity with more meteorites that are thought to have condensed from conventional imaging in collaboration with a number the primitive solar nebula can be used to help to of medical institutions. Applications include define better models for the differentiation and • Biomedical Imaging. Synchrotron based evolution of the earth. imaging techniques can provide high resolution Materials Sciences images using differences in refraction and scattering • Materials scientists are utilising XAS to of X-rays as they pass through soft tissue providing determine the nature of ion-implantation-induced genuine soft tissue contract with micrometre scale disorder in semiconductor substrates with application resolution. In mammography phase contrast imaging to both electronic and photonic device fabrication. provides an increase in contrast by as much as 25 • The geometry of impurity ions in doped crystal over conventional techniques with enormous systems can be determined with XAS. In many consequential benefits for the community. Lung systems the assumption that an impurity ion simply Imaging. Recently, techniques have been developed replaces a host ion without any site distortion is that allow the identification of local variations in lung invalid. Whereas the host crystal can be accurately function caused by diseases such as asthma and structurally characterised by x-ray diffraction, XAS is chronic obstructive pulmonary disease as well as the only way to get direct structural information of an testing procedures for the efficacy of pharmaceuticals impurity ion. Such information can be essential for a on respiratory dysfunction. full understanding of impurity-doped crystal systems. • Advanced Materials and manufactured These doped systems are often photonic devices that Products. Applications include studies of show energy up-conversion and spectral hole- precipitation and voids in industrially important light burning. An example under study by Australian metal alloys, membranes in advanced fuel cells, scientists is the stabilization of Sm(H) ions in borate fracture in ceramics, investigation of micro-nano crystals.

28 Structured devices by micro-Ct, study of porosity in relationships between crystal and electronic structure, oil bearing rocks and study of stress in advanced bulk vs surface states and in the end reactivity of materials. materials. Gas Phase Studies. Angle resolved photo-electron- • Radiotherapy. This area is under development. ion coincidence spectroscopy allows the study of The specific advantages of synchrotron radiation is electron-ion momentum vector correlations and the production of variable energy microbeams. reveal intermolecular scattering and associated interference. Other techniques can be used to study 3.6 Small and Wide Angle Scattering coherence in atomic physics, intrinsic width of atomic states and rotational-vibrational, frag- There is a growing community of scientists using mentation modes of molecules as well as inner-shell small angle scattering techniques. In addition to a effects. number of laboratory based X-ray facilities, the Adsorbate Studies. Specific areas of study here ASRP has a major involvement in the development include the identity and bonding of the successive of the SAS beamline at ChemMatCARS, APS, and a surface-intermediates in various CVD processes, the growing community utilising the AUSANS facility characterisation of carbon nano-tubes, gallium nitride on the HTFAR reactor and proposed facilities on the nano-wires, and silicon quantum-wire arrays. Replacement Research Reactor. The community has expressed a desire to site the beamline on a 22m 3.8 Soft X-raiys undulator source. To minimise Q for the facility it is There is a large Australian community principally planned to use the maximum beamline length that based on laboratory sources although the ASRP is can be accommodated within the synchrotron establishing an instrument station on the Taiwan building. Small angle and wide angle scattering has Light Source. The main activity is X-ray absorption applications in many areas od science including the spectroscopy for the lighter elements, X-ray photo study of: spectroscopy (XPS) and X-ray excited Auger electron spectroscopy (XAES). The proposed • Mesoporous materials undulator (55 mm period) covers the required energy • Self assembly systems range for these studies. The beamline is needed • Food science primarily for XAS and XPS, although there are other significant research applications such as photo- • Fibres desorption. Threshold XAES can be undertaken in • Membranes and crystallization studies any end-station equipped for XPS. Threshold XAES • Colloids is less generally applicable and less developed than • Proteins in solution XAS or XPS, but is potentially able to provide • Polymers information on interfacial species that is difficult to • Composite materials obtain by other spectroscopic techniques, and is currently used by some Australian researchers. X-ray 3.7 VUV Beamline emission spectroscopy (XES) also provides valuable The VUV beamline is presently modelled on the information, and is being used increasingly, but this proposed VUV beamline planned for the Canadian technique is best carried out in a purpose-built end- Light Source. Applications include station. It is not anticipated that a capability for XES • Angle Resolved Photoelectron Spectroscopy. would be established on beamline 5 during the initial This is the pre-eminent technique for the elucidation operating period. of the electronic structure of atoms molecules and solids. Soft X-ray absorption spectroscopy • Solid State Studies. These include understanding The other main reason a soft X-ray beamline is the properties of shape memory alloys, of colossal- needed for XAS is to enable the investigation of magneto-resistance alloys and of strongly correlated surfaces, near-surface interfacial layers and thin materials such as cobaltates and high temperature films. In these cases, all elements of atomic number superconductors. Photoemission from the valence greater than 3 are potentially of interest. For XAS in band is very attractive for studying chemisorption on the hard X-ray range, absorption is commonly semiconductor surfaces e.g. chemisorption of measured directly in transmission mode, but this hydrogen. The study of low binding energy core mode is rarely used with soft X-rays. Instead, lines of vacuum fractured, conducting (or small band absorption is usually measured indirectly by gap) mineral single crystals, in conjunction with determining the total electron yield (TEY), partial detailed valence band studies can illuminate inter- electron yield (PEY), Auger electron yield (AEY) or

29 fluorescence yield (FY). Each of these yields is greatest importance, but of almost equal importance associated with a different analysis depth, ranging is the high photon flux which allows high energy- from the outermost few run to more than 100 run. It resolution to be selected in the monochromator is possible to measure these yields simultaneously, resolution us transmission trade-off. The high flux and thereby obtain information towards the assembly also allows photoelectron diffraction measurements of a non-destructive chemical depth profile. Ion to be made. beam sputtering in association with conventional XPS, or dynamic secondary ion mass spectrometry, 3.9 Vibrational and Optical Spectroscopy are able to provide a destructive elemental depth The first beamline of this type will be based on a profile, but an ion beam can alter the chemical state bending magnet with the collection of as large an of an element in the sputtered surface layer. XAS for angular spread as possible. In the configuration of surface and thin film studies may be carried out at a the vacuum system it is planned to make provision fixed angle of incidence of the X-ray beam on the for up to two addition beamlines. The scientific specimen, or the angle of incidence may be varied research undertaken will be extremely varied, for from perpendicular to glancing. Angle-dependent example: XAS is a very important and widely-used technique • THz research for the study of orientation effects in thin films, and • Studies on the uptake of drugs in living cells in of the alignment of adsorbed monolayers or real time multilayers. • Evaluation of pharmaceutical quality • Sensitive forensic science studies X-ray photoelectron spectroscopy • Rapid turn-around evaluation of environmental Conventional XPS (including conventional XAES) is and mineralogical specimens the most important and versatile technique for the • In situ study of corrosion processes. chemical characterisation of the surface of a material. In conventional XPS, mono-chromatised soft X-rays 3.10 General purpose microprobe of fixed energy are obtained from an aluminium This proposed beamline has a very strong industrial anode, and because this photon energy is near 1.5 emphasis. It is intended to be a high throughput, keV, depending on the binding energies of the core rapid turn around facility that is available on a electrons of interest, the photoelectron kinetic commercial basis for Australian industry, especially energies are such that the typical analysis depth is 2— the mining industry. The resolution of the instrument 5 nm. Clearly only a small proportion of this analysis will be in the 4 - 20 um range. The instrument depth can be considered to be the true surface layer, station will combine X-ray fluorescence with X-ray and only for very smooth surfaces can the situation diffraction. Specific applications include be improved by adopting a low electron take-off angle. In synchrotron XPS, the photon energy can be • Geochemical. The capacity for simultaneous tuned to vary the kinetic energy of the ejected XRF and XRD will enable the relationship between photoelectrons, thereby varying the analysis depth. trace elements and host phases to be established. In particular, a photon energy can be selected to • Environmental (Acid Mine Drainage). The result in the photoelectrons of interest having a dual XRF-XRD mapping facility will enable the kinetic energy near 45 eV, the energy for which the identification of reaction and reprecipitation layering inelastic mean free path is a minimum. In this way, on mineral surfaces as a function of weathering. the surface sensitivity of XPS can be maximised and • Manufacturing. Examples include dual XRF- an analysis depth of the order of two atomic layers XRD study of aging of both plastics and alloys to can be achieved. By increasing the photon energy, form microcrystalline domains sometimes the analysis depth is increased and information accompanied by elemental diffusion. Measurement towards a non-destructive chemical depth profile can of stress/strain as a function of diffusion processes be obtained. In synchrotron XPS, the photon energy that occur on corrosion, welding and annealing is can also be tuned to alter the photo-ionisation cross- another area of extensive application. section for the electrons of particular interest. In practice, it is often highly desirable to optimise the 3.11 Lithography cross-section to enhance the sensitivity for a In Phase I it is proposed to install at least one particular element, or to change the relative cross- lithography beamline. This beamline will be set up section for a sub-shell in two elements, but of course for large scale production of micro-devices and will in both cases, a concomitant change in the depth complement the existing laser laboratory at the analysed would occur. Thus, in synchrotron XPS, it nearby Minifab Facility. Lithography and DXRL are is the tunability of the photon energy that is of often used as part of a process called LIGA, for the

30 fabrication of micro parts. LIGA is trie German 4. Status of the Project acronym that stands for the individual components of the process: Lithography, Galvanoformung The schedule for completing the project is shown in (Electroplating), Abformung (Replication). Unlike Table 3. The contract for the building has already other processes at the synchrotron, LIGA is a been let. "manufacturing tool" and not a diagnostic tool. LIGA uses synchrotron radiation to expose photosensitive The current activities include resist with a defined pattern from a specialised mask, • Design and construct tender for the building to make 3D devices with high aspect ratio awarded (height/width), smooth sidewalls and wall angles approaching 90 degrees. During synchrotron • Injection system preferred tenderers exposure, the substrate and mask are: mounted shortlisted together on a scanner plate which is scanned in • De velopment of beam! ine proposals in directions x, y, 0 and C1 to expose the desired area. conjunction with user community • Interaction with research community to The LIGA process runs complementary to other define beamline requirements microfabrication processes and the respective parts • Ongoing design of the beamlines. are often put together to form a larger device. Examples of devices containing LIGA fabricated parts include: Acknowledgements The authors are indebted to all members of the Microspectrometer (UV to IR) International Science Advisory and National Science Spectro-pen (Dr Lange Company) Advisory Committees (Chair - F. Larkins) for the Bilirubin Gauge (SpectRx) Australian Synchrotron and advice from G. Gopal on Micro-optical distance sensor undulators. In addition, T. Warwick and D. Cookson Micro-wave cavity devices have provided preliminary design details for several Micro-fiuidic reactors of the proposed beamlines. The beamline schematics Fibre optic couplers have been provided by A. Hobbs. Fibre splitters

Table 3 Construction Schedule

2003 Construction works commence Late 2004 Building complete Early 2005 Injection system assembly commences Late 2005 Injection system commissioned - Storage ring assembly underway Mid 2006 Storage ring commissioning and beamline installation commence Early 2007 Machine commissioning complete During 2007 & 2008 Progressive commissioning and tuning of the initial suite of beamlines

References

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