The Australian Synchrotron - A Progress Report  J BOLDEMAN", A JACKSON", G SEABORNE", R. HOBBY and R GARRETTb

"Australian Synchrotron Project, Level 17,80 Collins St, Melbourne bAnsto, PMBl, 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  Synchrotron radiation is emitted when electrons,  for example, travelling with velocities close to the  speed of light are bent in a magnetic or electrostatic  field. The electromagnetic radiation so released,  tangential to the electron path, is enormously more

intense than that from laboratory X-ray sources, the  radiation is emitted in a broad energy spectrum and  specifk energies or wavelengths can be selected for  experimental applications. The radiation is also

emitted with a very small divergence with respect  to the plane of the electron beam. Synchrotron  radiation has become a key analytical tool with

wide scale applications in the materials and  chemical sciences, molecular environmental  science, the geosciences, nascent technology and  defence related research among many fields. As a  consequence, more than 80 international

synchrotron facilities are either in operation or  planned. An evaluation in 1999 [l] indicated that  after several years of operation, an Australian based  facility would have an Australian user community

of approximately 1200 different researchers and a  possible international cliental of 350. In response  to this opportunity for outstanding wealth  generation, the Victorian Government has  committed $157 M towards the construction of a  national synchrotron faciIity. The total cost in  Phase I including beamlines and experimental

stations is $206M. The design objectives for the  Australian synchrotron were to satisfy the research  requirements of 95% of Australian user needs and  to satisfy all of those of Australian industry.  Naturally, the facility needed to be of world class  but had to fit within the budget that might be

expected for an Australian facility. A Feasibility  Study commissioned by the Federal Government

and completed in 1998 [2] recommended that a  compact mid energy facility similar to that  proposed for Canada [3] and one in the planning  stage for the Stanford Linear Accelerator  Laboratory [4] would be an ideal choice. Thus the  recommended energy for the facility was

3 GeV.

The facility would also need to be equipped with at  least 9 different beamlines in Phase I to satisfy the  design objectives.

2. The Boomerang Storage Ring  The Australian Synchrotron is being constructed by  the Victorian Government on a site adjacent to  Monash University in Melbourne. The facility is  based on the Boomerang Storage Ring which has a  DBA structure (Figure 1) with 14 superperiods.  Each cell comprises two dipoles (D), six

quadrupoles (Q) and seven sextupoles (S) separated  by appropriate drift spaces. The dipoles have  modest gradient fields to provide set horizontal  defocussing. Initially, the lattice was planned to  have 12 fold symmetry with a circumference of

approximately 184 - 189 m [5]. However  consideration started to be given to a larger lattice  and finally it was decided that the best performance

versus cost option for an Australian based facility  would be to have 14 periods for the lattice with a  circumference of 216 m [ 6 ] .  This allowed two  additional straight sections for insertion device

based beamline facilities and also reduced the  emittance by approximately 35%. The key  parameters are listed in Table 1 .  The design  objective was to achieve a low emittance in a  relatively compact circumference that had an  excellent dynamic aperture and was robust with  respect to potential construction aberrations.

Table 1 Basic Properties of the Lattice

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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.

5 m

S

I s

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 0 Microbeam Applications 14%

to cater for the requirements of 95% of the research o Biotechnoloev 14%

The strategy for the new Australian Synchrotron is e Materials Research 21%

interests of the Australian community. The size of  the community has increased over the last 10 years  principally through the auspices of the Australian  Synchrotron Research Program and the current  community numbers more than 300. Demographic  projections based on international experience

suggest that the Australian based research  community in the mature period (after 5 years of  operation) should be approximately 1200. The  present activities of this community according to  research areas (based on ASRP data) is as follows:

"9

o X-ray Physics 12%

o Minerals and Mining 12%

Polymers /Soft X-rays 9%  o Chemical Sciences 9%

o Environmental Science 3%

o IT Applications 6%

Ultimately, the facility will attempt to cater for all  of these applications and prospective new  opportunities as they arrive. The Australian  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

2 - 20 keV Protein Crystallography (MAD)  5.5 - 20 keV Protein Crystallography (MAD) and SmalMoleculesl  5.5 - 25 keV Microfocus  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) 5.5 - 35 keV

Visible Ultra Violet (VUV) 10 - 350 eV

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

LTGA bending magnet 2 - 25 keV

undulator 2 - 100 eV Circular Dichroism

bending magnet  22 mm undulator  22 mm undulator

22 mm undulator  185 mm undulator

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Funding is being sought for as many of these  proposals as possible. Design of these beandines is  proceeding and it is hoped to have as many  operational on day 1 as possible. It is clear from the

Table that high brightnesdflux on target is required  in the 10 - 20 keV range which of course was the  principal argument for the 3 GeV ring. To provide  competitive performance in this region a 22 mm in  vacuum undulator is under consideration. For the

Bonnierang 22 tnni IJndulator

0 f 10 IS 261 2.5

Energy (keV)

FIGURE 2 Brightness plots for the 22 m Undulator

Figure 2 showing harmonics to 9 indicates that  there is excellent brightness to at least 20 keV. The  brightness for harmonics 1 to 5 is shown in Figure  3. The photon flux that is achievable on the

Boomerang bending magnets is shown in Figure 4  and that for a high performance wiggler (61 mm  period, K= 10.8) is shown in Figure 5. In recent  times, considerable advances have been made in

soft X-rays a 55 mm period out of vacuum  undulator is an obvious candidate. Figure 2 and 3  presents the brightness that would be achieved &om

the lattice operated in its minimum. emittance mode  for both of these IDS respectively[4]. The  calculations presented in the figures include the  impact of the beam energy spread but not potential

magnet errors.

FIGURE 3 Brightness plots for 55 m Undulator

the performance of Insertion Devices and by the  time a decision is needed on appropriate IDS there  may be new opportunities.

Comments on the various beamline proposals are  presented below. The maximum. beamline length  (to the target) that can be considered within the  confines of the synchrotron building is 40 m.

, ...............................................................................

I I t

.................. < I  ............. L _ _ I _ _ _ I _ ~ . L I _ L !  ........................... .! j 1.ow 1.OE3 1.IIE.l 1.urzj: PhotMl EtkWgy [ev] t . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .   FIGURE 4 Flux from Bending Magnet FIGURE 5 Flux fiom 6 1 mm Wiggler

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3.1 Protein Crystallography  Macromolecular or protein crystallography (PX) is a  method for determining the structures of large  biological molecules, specifically proteins and  Protein Crystallography is recognised internationally

as one of most important applications (if not the most  important) of synchrotron facilities. The Intellectual  Property generated in this science is the basis on  which many modern drugs are developed. It also  provides critical information on life science  processes. As a consequence all major OECD  nations have invested heavily in synchrotron  facilities. At the 1'' October this year, 22,700 protein  structures had been deposited in the Protein Data  Bank of which 19,285 had been determined by X-ray  DtMi-action.

Two beamlines are planned for protein

crystallography  as part of a comprehensive program  in this vital area of research. One of these will be a  conventional beamline sited on a bending magnet that  will cater for high throughput studies, exploratory  studies and rapid response activities. The second will  be based on a 22 nun in vacuum undulator providing  microfocus beams probably to an instrument station  at 38.5 m. Without d e h i n g  slits it is hoped to focus  the beam to 100 pm horizontally and 50 pm within a  total divergence of 0.2 mad. For smaller crystals

slits will be required to reduce the beam size. This  beamline will also cater for the small molecule  community. Both beamlines will be multi-wave  anomalous dispersion (MAD) capable. It is also  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 Beamline

The micro-focus protein crystallogra hy beamline  will deliver a competitive 1.6 * 10 I '  photons per  second into a 100 x 50 micron spot size with a total  divergence of 0.2 millirads at the Se edge with a  bandwidth of 0.1%. For the bending magnet  beamline which would have a greater beam  divergence the flux is not greatly lower. The  experiments performed at the facilities for  macromolecular crystallography at third generation

sources include:  0 Monochromatic crystallography: Utilising high

flux and brilliance, improved collimation, and  the fact that the experimenter can choose the  energy of the input photons. High brilliance is  important for measuring diffraction data of  extremely small and weakly diffracting crystals.  Micro-crystals of proteins and small molecules

(10-30 micron size, which are, in general,  difficult to grow and diffract weakly) can be  studied. Also, data from large protein complexes  and virus crystals, as well as ultra high (atomic)  resolution data can be collected.  0 Multi-wavelength technique: Multiple

Anomalous Dispersion (MAD) is one of the  most rapid methods of determining the structure  of biological macromolecules. It requires highly

collimated, variable-wavelength X-rays. This  technique is expected to be performed on less  demanding, highly diffracting crystals.  Special Experiments: Some special experiments can  include the Laue diffraction or white-beam (or pink-  beam) method. In this case, the macromolecular  crystal is exposed to a widc range of X-ray energies,

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3.2 Microfocus Bearnline

Australian use of international synchrotron facilities  has been characterised by an unusually high  proportion of use of microprobe facilities. At other  institutions in Australia there are two proton  microprobes and one heavy ion microprobe. This  focus on microprobes results from the importance of

mineral exploration and extraction to the Australian  Australian use of international synchrotron facilities  has been characterised by an unusually high  institutions in Australia there are two proton  microprobes and one heavy ion microprobe. This  focus on microprobes results from the importance of

mineral exploration and extraction to the Australian  economy. The requirements for this beamline  include the capability of focussing the X-ray beam at  the target to spot sizes as small as 0.2 pm, beam

energies to 20 keV and of course the highest flux that  can be obtained from the facility with these  specifications.  The microfocus beamline finds applications in an

extremely wide variety of scientific and technical  areas including

Biotechnology. Simultaneous elemental and  chemical mapping of tissues, cells etc provides  A better understanding of diseases, immune  processes as well as toxin and heavy metal

uptake of tissues down to a sub-micron  cellular level as well as the Eunctionality of a  large number of metalo-proteins.  * The mapping of the distribution and

biotransformations of anti-cancer and other  drugs in cultured cells and tissues for  improved drug design and delivery.  * Two-dimensional scanning of

chromatography gels in which all of the  proteins of an organism or an organ are  separated will enable all of the

metalloenzymes to be mapped, especially  those containing Se and S.  A better understanding of the distribution,  uptake and metabolism of metal-containing  pharmaceutics in cells and tissue for the

development of better and safer drugs. XAS  on a sub-micron scale can provide structural  chemical information regarding the  intracellular biotransformation of the drugs.  A range of different metal oxides can be  attached to different sequences of DNA or  RNA sequences and scanned by a nanoprobe  to obtain gene maps.  Environment. Increasingly the study of toxins in the  environment and their pathways requires submicron

resolution as well as the ability to determine their  oxidation state.

*

Geoscience. Micron resolution is essential in the  earth sciences in order to deal with typical natural  sample sizes. The major analytical techniques such as  electron probe, laser ablation ICPMS and ion probes  like P E E  and S H R W  have micron-scale

resolution. The ability to produce an element map a  sample and to determine the oxidation state as well  on how a particular element is bound or coordinated  is the scientfic ‘quantum leap’ offered by the

synchroqon microprobe over all other microprobe  techniques. It leads in particular to  * Increased efficiency of mineral processing  * More eEcient management of mine wastes

and mining operations  e A better understanding of ore forming  processes can be used in predictive  exploration.  * Improve understanding of the geological

conditions leading to the release of S.  Tiny inclusions of melt trapped in zircon  crystals > 4 billion years old can be analysed  for chemical indicators of the hydrosphere

and atmosphere at that time.

Materials. Ion microprobes are used in many areas  of Materials research, which can be enhanced by  synchrotron microprobes to take advantage of the  lower sample damage rate of x-rays compared to ions

and the ability to obtain physical and chemical  information such as  surface corrosion, micro-pitting and wear  mechanisms of materials

a better understanding of the chemistry and  interaction processes of impurities and  contaminants in materials  debonding and delamination processes,

particularly related to composite materials  on on a micro scale  polymer crystallisation and seeding of polymers  for industry to produce consistent quality

and reduce refuse  grain boundaries, impurities, charge transport  and collection efficiency, lifetime,

recombination, band gap in photovoltaic  materials to improve efficiency in photovoltaic  materials  a better understanding of the structure, porosity,  composition of fuel cell electrodes as well as  their poisoning, impurity distribution and

oxidation to improve the performance and  durability of fuel cells.

0

*

e

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3.3 Powder Diffraction

Australian science has had a long history at the  forefront of powder ditfi-action studies with neutrons  as well as X-rays. Experiments performed on the  Powder X-ray dieaction beamline di&actometer  will be directed mainly towards determining the

atomic structures of powdered crystalline samples.  Such studies fall into the following broad classes:  e

e

Structural properties relations in transition metal  oxides  Accurate inorganic structures of materials for  technical applications like superconductors,  functional materials and porous materials

e In situ measurements of reaction kinetics and  structural changes. For example, temperature  pressure dependent dehydration mechanisms,  porous materials (zeolite-like materials) and  temperature and pressure dependent phase

transitions (including changes of symmetry,  and superlattice reflections)  Pair distribution fbnction analysis of disordered  materials including superconducting cuprates,

semicrystalline polymers and nanocrystalline  particles  0 Disoredered and defect structures.

A possible configuration of the beamline is shown in  Figure 7.

Figure 7 Powder Diffraction Beamline

3.4 X-ray Absorption Spectroscopy  Approximately 25 % of all use of synchrotron  facilities by Australian scientists involves application  of XAS techniques. Some applications include  Biochemical Sciences

Carcinogens. XAS i s  being utilised for the first  time to characterise the structures of a range of  reactive Cr(VI), Cr(V) and Cr(1V) complexes with  biological reductants. Many Cr(I1I) complexes,  which are the ultimate products of the reductions  have also been characterised. This research will

provide important new insights into metal-based  toxicology.  0 Anti Cancer Drugs. Extensive XAS investigations

of Co and Pt anti-cancer drugs are in progress with  the aim of developing new technologies that enable  the determination of the oxidation state in-situ in

different regions of tumours and in models of  hypoxic tumours. This will enable the rational tuning  of the reduction potentials to achieve on the  relationship between reduction potential and the

extent of activation in hypoxic environments.

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0 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  characterisation of new drugs in the solid state,

solution, pharmaceutical formulations and biological  fluids. This research has been essential in  determining the stability of the drugs in

pharmaceutical preparations and in understanding the  pharmacology.  Chemical Sciences  D-block elements. XAS studies are in progress to

better understand the influence of redox or charge  state on the electronic and molecular structure of  metal complexes or clusters so as to better anticipate  (and ultimately control) the reactions and reactivity

of transition metal catalysts. The metal clusters that  lie at the active site of the nitrogenase and

hydrogenase enzymes provide challenging, but  important, target molecules for this work. Techniques  have been developed to permit in-situ spectroscopic  examination of reactive electro-generated species  including the use of IR and UV-Vis spectroscopies  to complement direct structural characterisation with  XAS ,  Earth Sciences

e XAS is being used to identify the metal

complexes involved in the transport of ore-metals  (Cu, Au, Ag) by supercritical hydrothemal solutions  to form economically important ore-deposits  The oxidation state of elements in magmas  (silicate melts) is being determined with XAS. The  abundance of elements in the mantle relative to  meteorites that are thought to have condensed from

the primitive solar nebula can be used to help to  define better models for the differentiation and  evolution of the earth.  Materials Sciences

Materials scientists are utilising XAS to  determine the nature of ion-implantation-induced  disorder in semiconductor substrates with application  to both electronic and photonic device fabrication.

0 The geometry of impurity ions in doped crystal

systems can be determined with XAS. In many  systems the assumption that an impurity ion simply  replaces a host ion without any site distortion is  invalid. Whereas the host crystal can be accurately

structurally characterised by x-ray diffraction, XAS is  the only way to get direct structural information of an  impurity ion. Such information can be essential for a  full understanding of impurity-doped crystal systems.

These doped systems are oRcn photonic devices that  show energy up-conversion and spectral hole-  burning. An example under study by Australian  scientists is the stabilization of SmOI) ions in borate

crystals.

Physical Sciences and Engineering  e Experimental and theoretical investigations

have been combined to produce absolute XAS  measurements to enable new critical tests of  relativistic atomic, molecular and solid-state dogma.  This program has provided calibration on two new

axes previously unavailable for either experimental  or theoretical studies.  e Micro- and meso-porous materials, such as

zeolites and their analogues, are of major importance  as the substrates for catalysis - chiefly to prepare fine  chemicals, crack heavy hydrocarbons, adsorption-  separation and polymer synthesis. The micro/meso-  porous structure of such materials can be doped with  metals like Mn, Mg, Cu, Zn, Ni and Co to

incorporate metals in the framework and generate  microscopic centres for catalysis. XAS experiments  yield atom-specific mformation of the absorber  environment useful for designing and developing

efficient catalytic systems.

New Science Initiatives  0 Nanoscience

0 IJltra-Dilute Measurements

0 Fast-Scanning/Time-Resolved Measurements

3.5 X-ray Imaging  Phase contrast imaging is an area of research that has  also had considerable activity in Australia. It is  proposed to combine this activity with more

conventional imaging in collaboration with a number  of medical institutions. Applications include  Biomedical Imaging. Synchrotron based  imaging techniques can provide high resolution  images using differences in refraction and scattering  of X-rays as they pass through soft tissue providing  genuine soft tissue contract with micrometre scale  resolution. In mammography phase contrast imaging  provides an increase in contrast by as much as 25  over conventional techniques with enormous  consequentid, benefits for the community. Lung  Imaging. Recently, techniques have been developed  that allow the identification of local variations in lung  function caused by diseases such as asthma and

chronic obstructive pulmonary disease as well as  testing procedures for the efficacy of pharmaceuticals  on respiratory dysfunction.  e Advanced Materials and manufactured

Products. Applications include studies of  precipitation and voids in industrially important light  metal alloys, membranes in advanced fuel cells,  fracture in ceramics, investigation of micro-nano

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Structured devices by micro-Ct, study of porosity in  oil bearing rocks and study of stress in advanced  materials.

e Radiotherapy. This area is under development.  The specific advantages of synchrotron radiation is  the production of variable energy microbeams.

3.6 Small and Wide Angle Scattering

There is a growing community of scientists using  small angle scattering techniques. In addition to a  number of laboratory based X-ray facilities, the  ASRP has a major involvement in the development  of the SAS beamline at ChernMatCARS, APS, and a

growing community utilising the AUSANS facility  on the HIFAR reactor and proposed facilities on the  Replacement Research Reactor. The community has  expressed a desire to site the beamline on a 22m  undulator source. To minimise Q for the facility it is

planned to use the maximum beamline length that  can be accommodated within the synchrotron  building. Small angle and wide angle scattering has  applications in many areas od science including the

study of

Mesoporous materials  Self assembly systems  Food science  Fibres  Membranes and crystallization studies

Colloids  Proteins in solution  Polymers  Composite materials

3.7 VUV Beamline  The W V  beamline is presently modelled on the  proposed VUV beamline planned for the Canadian  Light Source. Applications include

Angle Resolved Photoelectron Spectroscopy.  This is the pre-eminent technique for the elucidation  of the electronic structure of atoms molecules and  solids.  e Solid State Studies. These include understanding  the properties of shape memory alloys, of colossal-  magneto-resistance alloys and of strongly correlated  materials such as cobaltates and high temperature  superconductors. Photoemission from the valence  band is very attractive for studying chemisorption on

semiconductor surfaces e.g. chemisorption of  hydrogen. The study of low binding energy core  lines of vacuum fractured, conducting (or small band  gap) mineral single crystals, in conjunction with

detailed valence band studies can illuminate inter-

relationships between

crystal and electronic structure,

bulk vs surface states and in the end reactivity of  materials.  Gas Phase Studies. Angle resolved photo-electron-  ion coincidence spectroscopy allows the study of

electron-ion momentum vector correlations and  reveal intermolecular scattering and associated  interference. Other techniques can be used to study  coherence in atomic physics, intrinsic width of

atomic states and rotational-vibrational, frag-  mentation modes of molecules as well as inner-shell  effects.  Adsorbate Studies. Specific areas of study here  include the identity and bonding of the successive

surface-intermediates in various CVD processes, the  characterisation of carbon nano-tubes, gallium nitride  nano-wires, and silicon quantum-wire arrays.

3.8 Soft X-rays  There is a large Australian community principally  based on laboratory sources although the ASRP is  establishing an instrument station on the Taiwan  Light Source. The main activity is X-ray absorption

spectroscopy for the lighter elements, X-ray photo  spectroscopy ( X P S )  and X-ray excited Auger  electron spectroscopy (XAEB). The proposed  undulator (55 mm period) covers the required energy  range for these studies.The beamline is needed  primarily for XAS and XPS, although there are other

significant research applications such as photo-  desorption. Threshold XAES can be undertaken in  any end-station equipped for X P S .  Threshold XAES  is less generally applicable and less developed than  XAS or XPS, but is potentially able to provide  information on interfacial species that is difficult to  obtain by other spectroscopic techniques, and is  currently used by some Australian researchers. X-ray

emission spectroscopy (XES) also provides valuable  information, and is being used increasingly, but this  technique is best carried out in a purpose-built end-  station. It is not anticipated that a capability for XES

would be established on beamline 5 during the initial  operating period.

Soft X-ray absorption spectroscopy  The other main reason a soft X-ray beamline is  needed for XAS is to enable the investigation of  surfaces, near-surface interfacial layers and thin  films. In these cases, all. elements of atomic number

greater than 3 are potentially of interest. For XAS in  the hard X-ray range, absorption is commonly  measured directly in transmission mode, but this  mode is rarely used with soft X-rays. Instead,  absorption is usually measured indirectly by

determining the total electron yield (TEY), partial  electron yield (PEY), Auger electron yield (my) or

29

fluorescence yield (FY). Each of these yields is  associated with a d8erent analysis depth, ranging  from the outermost few nm to more than 100 nm. It  is possible to measure these yields simultaneously,

and thereby obtain information towards the assembly  of a non-destructive chemical depth profile. Ion  beam sputtering in association with conventional  X P S ,  or dynamic secondary ion mass spectrometry,

are able to provide a destructive elemental depth  profile, but an ion beam can alter the chemical state  of an element in the sputtered surface layer. XAS for  surface and thin film studies may be carried out at a  fixed angle of incidence of the X-ray beam on the

specimen, or the angle of incidence may be varied  from perpendicular to glancing. Angle-dependent  XAS is a very important and widely-used technique  for the study of orientation effects in thin films, and  of the alignment of adsorbed monolayers or  multilayers.

X-ray photoelectron spectroscopy  Conventional X P S  (including conventional XAES) is  the most important and versatile technique for the  chemical characterisation of the surface of a material.  In conventional X P S ,  mono-chromatised soft X-rays  of fixed energy are obtained from an aluminium

anode, and because this photon energy is near 1.5  keV, depending on the binding energies of the core  electrons of interest, the photoelectron kinetic  energies are such that the typical analysis depth is 2-

5 nm. Clearly only a small proportion of this analysis  depth can be considered to be the true surface layer,  and only for very smooth surfaces can the situation  be improved by adopting a low electron take-off

angle. In synchrotron X P S ,  the photon energy can be  tuned to vary the kinetic energy of the ejected  photoelectrons, thereby varying the analysis depth.  In particular, a photon energy can be selected to

result in the photoelectrons of interest having a  kinetic energy near 45 eV, the energy for which the  inelastic mean free path is a minimum. In this way,  the surface sensitivity of X P S  can be maximised and

an analysis depth of the order of two atomic layers  can be achieved. By increasing the photon energy,  the analysis depth is increased and information  towards a non-destructive chemical depth profile can  be obtained. In synchrotron X P S ,  the photon energy

can also be tuned to alter the photo-ionisation cross-  section for the electrons of particular interest. In  practice, it is often highly desirable to optimise the  cross-section to enhance the sensitivity for a  particular element, or to change the relative cross-

section for a sub-shell in two elements, but of course  in both cases, a concomitant change in the depth  analysed would occur. Thus, in synchrotron XPS, it  is the tunability of the photon energy that is of

greatest importance, but of almost equal importance  is the high photon flux which allows high energy-  resolution to be selected in the monochromator  resolution vs transmission trade-off. The high flux

also allows photoelectron dBaction measurements  to be made.

3.9 Vibrational and Optical Spectroscopy  The first beamline of this type will be based on a  bending magnet with the collection of as large an  angular spread as possible. In the configuration of

the vacuum system it is planned to make provision  for up to two addition beamlines. The scientific  research undertaken will be extremely varied, for  example:

* THzresearch  Studies on the uptake of drugs in living cells in  real time  * Evaluation of pharmaceutical quality

Sensitive forensic science studies  Rapid turn-around evaluation of environmental  and mineralogical specimens  In situ study of corrosion processes. e

3.10 General purpose microprobe  This proposed beamline has a very strong industrial  emphasis. It is intended to be a high throughput,  rapid turn around facility that is available on a  commercial basis for Australian industry, especially  the mining industry. The resolution of the instrument  will be in the 4 - 20 pm range. The instrument

station will combine X-ray fluorescence with X-ray  diffraction. Specific applications include  * Geochemicgt: The capacity for simultaneous  XRF and XRD will enable the relationship between

trace elements and host phases to be established.  * Environmental (Acid Mine Drainage). The  dual XRF-XRD mapping facility will enable the  identification of reaction and reprecipitation layering  on mineral surfaces as a function of weathering.

* Manufacturing. Examples include dual XRF-  X R D  study of aging of both plastics and alloys to  form microcrystalline domains sometimes

accompanied by elemental diffusion. Measurement  of stressktrain as a function of difision processes  that occur on corrosion, welding and annealing is  another area of extensive application.

3.11 Lithography  In Phase I it is proposed to install at least one  lithography beamline. T l s  beamline will be set up  for large scale production of micro-devices and will  complement the existing laser laboratory at the  nearby Minifab Facility. Lithography and DXRL are

often used as part of a process called LIGA, for the

30

fabrication of micro parts. LIGA is the German  acronym that stands for the individual components of  the process: Lithography, Qalvanoformung  (Electroplating), Abformung (Replication). Unlike  other processes at the synchrotron, LIGA is a  “manufacturing tool” and not a diagnostic tool. LIGA  uses synchrotron radiation to expose photosensitive  resist with a defined pattern from a specialised mask,

to make 3D devices with high aspect ratio  (heighvwidth), smooth sidewalls and wall angles  approaching 90 degrees. During synchrotron  exposure, the substrate and mask are mounted  together on a scanner plate which is scanned in  directions X, y, 0 and 4D to expose the desired area.  The LIGA process runs complementary to other  microfabrication processes and the respective parts

are often put together to form a larger device.  Examples of devices containing LIGA fabricated  parts include:

2003  Late 2004  Early 2005  Late 2005  Mid 2006  Early 2007  During 2007 & 2008

Microspectrometer (UV to IR)  Spectro-pen @r Lange Company)  Bilirubin Gauge (SpecfRx)  Micro-optical distance sensor

Micro-wave cavity devices  Micro-fluidic reactors  Fibre optic couplers  Fibre splitters

Construction works commence  Building complete  Injection system assembly commences  Injection system commissioned

- Storage ring assembly underway

Storage ring commissioning and beamline installation commence  Machine commissioning complete  Progressive commissioning and tuning of the initial suite of beamlines

4. Status of the Project

The schedule for completing the project is shown in  Table 3. The contract for the building has already  been let.

The current activities include  0

0 Injection system preferred tenderers

a

a

0

Design and construct tender for the building  awarded

shortlisted  Development of beamline proposals in  conjunction with user community  Interaction with research community to

define beamline requirements  Ongoing design of the beamlines.

Acknowledgements

The authors are indebted to all members of the  International Science Advisory and National Science  Advisory Committees (Chair - F. Larkins) for the  Australian Synchrotron and advice from G. Gopal on

undulators. In addition, T. Warwick and D. Cookson  have provided preliminary design details for several  of the proposed beamlines. The beamline schematics  have been provided by A. Hobbs.

Table 3 Construction Schedule

References

1. J. W. Boldeman (1999), “The Boomerang  Proposal Parts I - VII”, A Detailed Proposal  incorporating a preliminary storage ring design, civil  engineering design, capital and operating cost

estimates, stfling requirements and governance  issues submitted to the Department of Industry  Science and Technology, Australian Federal  Government. ASRP Document, December1 999.  2. J. W. Boldeman, R. Garrett, M. Murray, C.  Davenport and B. Whan, “A Feasibility Study for an

Australian Synchrotron Facility”, ASRP document  submitted to DIST.  3. L. 0. Dallin, I. Blomqvist, M. de Jong, E. Hallin,  D.S. Lowe and R. M. Silzer, “The Canadian Light

Source : Status Report”, Procs, 25’ ICFA Advanced  Beam Dynamics Workshop: “Shanghai Symposium  on Intermediate-Energy Light Sources”, Shanghai,  China, March 2002, page 42.  4. SPEAR 3 Design Report, SLAC Pubs, 1999.

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