Science

The Canadian Light Source is committed to scientific and technical excellence in all its endeavors. It will only support the construction of CLS scientific facilities that are truly "state of the art". When necessary, the CLS will assist its community in identifying another facility at which a proposed scientific program can be accommodated in an excellent manner.

Canadian Light Source Inc. will operate its facilities in recognition of the scientific and geographic diversity of its user base. Scientific facilities at the CLS will provide a wide range of scientific capability with a truly reliable user-friendly operation.

The concentration of its efforts will be in support of research in materials, environmental and life sciences.

Excellence in materials science

Phase I beamlines, with an expected materials science program, include the Mid IR spectromicroscopy, Variable Line Spacing Plane Grating Monochromator (5.5 to 250 eV), High Resolution Spherical Grating Monochromator (200 to 1900 eV), Soft X-ray Spectromicroscopy (250 to 2000 eV with arbitrary polarization) and micro-XAFS (5000 to 40000 eV, 2 mm x 2 mm photon spot).

Most of the early synchrotron users in Canada and worldwide used synchrotron radiation to study surfaces and materials (mainly physicists and chemists); this is still a very major use of synchrotron radiation in Canada and abroad. Techniques such as photoemission or photoelectron spectroscopy (often called XPS), along with XAFS, have been incredibly important for studying, for example, metals, alloys, semi-conductors, overlayers, nanomaterials, superconductors, and some non-conductors such as polymers, minerals, and the surface reactions of these materials with gases and liquids, and industrial oils. XPS has been a standard technique for studying surfaces of industrial products (at Surface Science Western at University of Western Ontario) such as used metals, polymers, and semiconductors; and XAFS measurements at the Canadian Synchrotron Radiation Facility have been very useful for determining the chemistry of S in coals, heavy oils and tribological films on automobile parts. More recently, techniques such as IR, PEEM and STXM mentioned earlier (along with XPS imaging) will give the chemistry of these materials (such as the polymer microstructure) and surfaces at very good (less than 0.1 micron for STXM) resolutions. In addition to physicists and chemists, many geoscientists are now using synchrotron radiation to study the chemistry of different minerals, meteorites, and glasses (and very small inclusions in these materials), and the surface reactions of many minerals. Canadians have, and are, making worldwide advances in synchrotron radiation techniques such as STXM and XPS. The PGM, SGM, and STXM /PEEM beamlines should give Canadians the best facilities in the world for doing both academic and industrial surface and materials studies.

Canadian scientists on CLS beamline teams are presently developing new synchrotron radiation techniques, or improving the performance of mature techniques, at U.S. facilities such as the Canadian Synchrotron Radiation Facility (CSRF) at the Aladdin synchrotron at the University of Wisconsin, the Advanced Photon Source (APS) in Chicago, or the Advanced Light Source (ALS) at Berkeley. For example, T.K. Sham, (University of Western Ontario) has developed a new technique at CSRF called XEOL (X-ray Excited Optical Luminescence), and has helped developed a new way of getting better resolution XAFS by monitoring the resonance Auger electrons. These techniques are not being used routinely at any other synchrotron source at present, but will be available on the PGM and SGM beamlines at the CLS. For the STXM/PEEM beamline, A.P. Hitchcock, (McMaster University) has been developing the highest resolution STXM instrument in the world at the Advanced Light Source, using interferometric control of the zone plate-sample distance; and S.G. Urquhart (University of Saskatchewan) has just started to operate the best commercial PEEM in the world at the Aladdin facility. H.W. Nesbitt, G.M. Bancroft and N.S. McIntyre (University of Western Ontario) have recently shown that a new Kratos XPS instrument at Surface Science Western (using a magnetic confinement charge compensation system) produces THE minimum resolution on non-conducting samples, and this instrument on the Canadian Light Source SGM beamline will give better resolution on non-conductors than at any present facility.

Excellence in environmental science

The hard x-ray micro-XAFS line will have a major impact on both academic and industrial research. XAFS can be obtained on virtually any type of environmental sample - gas, liquid, solid of any type (eg. amorphous, micro-crystalline or crystalline); and the detailed chemistry of almost all elements heavier than Ti at the ppm level can be obtained on very small amounts of sample. Academic researchers are proposing to determine the chemistry of many elements in environmental samples from minerals and micro inclusions in minerals, to soils, meteorites, particulates, glasses, coals, oils, mine tailings, etc. The CLS industrial effort is presently concentrating on the determination of the chemistry of As and Se in amorphous materials from mining operations. The oxidation state (As III, versus As V) and the detailed chemistry of As V (FeAsO4, versus adsorbed AsO4) can be readily obtained on these amorphous materials; and many regulatory agencies and mining companies need this information to predict the mobility and toxicity of the As. The technique is then incredibly useful to follow the biological uptake of toxic elements in biological tissue in plant and animal DNA and proteins, plant and tree roots and leaves, and even in human organs. The EXAFS beamline will also be able to obtain the concentration of nearly all elements in sample size of 2 microns by 2 microns; and the chemistry of those elements can then be obtained. It is apparent then that the XAFS beamline will be used by geoscientists in departments such as geology, geography, and soil science, by analytical chemists, and by many biological and medical scientists in biochemistry, plant and animal sciences, medical imaging and pathology.

Other beamlines in the first seven to be built at the Canadian Light Source, such as the SGM and STXM will also be extremely useful for characterizing the chemistry of the light elements in many of the above sample types - including the chemistry of C, N, O, P and S. The STXM and PEEM will enable microscopic images of those elements to be obtained on some of those samples at 100 nanometer spatial resolution. The IR beamlines will be very useful to obtain the chemistry and spatial distribution of light elements in many environmental samples, such as organic inclusions in rocks- at 5 micron spatial resolution. The volume recently produced for the Mineralogy Association of Canada (MAC) meeting in Saskatoon in June 2002 entitled: Earth, Environmental, and Material Sciences Applications, edited by Grant Henderson and Don Baker is an excellent primer in this area and can be obtained through the CLS or the MAC.

Excellence in the life sciences

There is a very large group of Canadian scientists that will be using the protein crystallography (PX) beamline to determine the atomic structures of biological macromolecules such as proteins by single crystal X-ray diffraction. Protein crystallography has shown exponential growth since the late 1970's when only about a dozen protein structures were known, and PX is an essential tool to all the biological scientists (academic and industrial) working in virtually all fields of biological and medical sciences. Crystal structures of proteins such as digestive enzymes, hormones, receptors and receptor and signaling proteins are critical to understand important physiological processes. Protein crystal structures of functional proteins of viruses are important to understand the mechanisms of virus infections, and to provide targets for virus control. Recent antiviral drugs against AIDS are enzyme inhibitors, and their design took advantage of detailed protein-drug interactions provided by crystal structures of the enzymes with the drugs--so-called structure function relationships. Similar detailed relationships are part of the strategy for the design of antibiotics and other drugs, and all major pharmaceutical companies are using SR sources to determine the structure of proteins with and without bound drug candidates. There is a major effort worldwide to sequence the complete genome of whole organisms, and to study the structure and function of all the proteins produced by those genes (so-called structural genomics or structural proteomics).

In addition, many researchers in the biotechnology, food and environmental sciences areas will require atomic structures of proteins from synchrotron radiation sources. Bacteria and plant proteins (enzymes) are being used to catalyze a wide variety of chemical reactions; for example, for food production, and degradation of wood by products and environmental pollutants. Powder diffraction is proving to be exceedingly useful for determining what drug polymorph is present in a sample. This is essential, because one polymorph may be active, and another one inactive.

In 2000, well over 3000 protein crystal structures were determined worldwide, and this tremendous increase is mainly due to the use of ultra-bright beams of synchrotron radiation such as will be available at the PX beamline at CLS. There are now at least 38 PX academic groups in Canada from Biochemistry, Biology, Biophysics, Chemistry, Microbiology, Immunology, Pharmacy, and Plant Science Departments, and all of those groups need to go to a synchrotron radiation facility to obtain atomic resolution on often very small crystals. Because of the very small photon beam sizes at the CLS PX beamline (about 50 microns by 150 microns), the very high fluxes into that spot size, and the ability to change wavelengths for MAD (multi-wavelength anomalous dispersion), it will be possible to obtain full atomic refinements on crystals with only 10 microns dimensions in all directions.

The infrared beamline will also be of great use to the medical sciences, and already Canadian groups in Winnipeg are using high resolution infrared imaging (at about 10 micron resolution) at a NSLS beamline sponsored by CLS to study damaged heart tissue in hamsters, and brain tissue damaged by Alzheimer's disease. The infrared technique is ideal for biological samples because the IR frequencies are unique for different functional groups and the analysis depth can be close to 1 mm. The XAFS line will also be very valuable for studying the chemistry and distribution of metals, such as described above in the environmental section. For example, researchers at the University of Western Ontario are already studying the chemistry and distribution of Fe in diseased livers at the APS.

The CLS is committed to providing excellence in analytical capabilities that support basic and applied research in each of the material, life and environmental sciences. There are significant communities of Canadian researchers in each of these broad fields whose programs would benefit substantially from the use of synchrotron-based tools.

Last modified: 2008-07-29 14:07:38