Inner shell excitation spectroscopy and microscopy

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My group develops and uses electron impact and X-ray based inner-shell excitation spectroscopic instrumentation and techniques for materials analysis. Gas phase electron impact studies at McMaster are combined with synchrotron radiation based materials analysis at spectroscopy and microscopy beamlines at the Canadian Light Source (CLS, Saskatoon) and the Advanced Light Source (ALS, Berkeley). Our forte is linking basic spectroscopic understanding, developed by fundamental experimental and computational studies of pure gaseous and solid materials, to materials analysis applications using novel instrumentation and methods, particularly soft X-ray microscopies. A major component of this program is the development of new instrumentation and new techniques. In the next 5 years we will: (1) expand the instrumentation and applications of X-ray spectromicroscopy, focusing in particular on areas exploiting the unique capabilities of the CLS spectromicroscopy beamline. These include mapping orientation of polymer and nanofibres, magnetism in biology, and wide energy range, multi-element studies. Work will also continue at the ALS, focusing on helping develop a next generation scanning transmission X-ray microscope, with sub-10 nm spatial resolution and 3d chemical imaging of frozen biological and environmental samples. Other advanced microscopies at McMaster - ultra-resolution electron microscopies (TEM, SEM), Raman and atomic force microscopy - are used also. (2) perform gas phase dipole and non-dipole electron scattering studies, as well as continue the exciting program in quasi-elastic electron scattering. This area uses home-built instrumentation that is unique. The dipole studies provide the spectroscopic foundation for our X-ray microscopy analytical work while the non-dipole instrument allows us to probe fine details of electron scattering interactions and aspects of the electronic structure of molecules that cannot be easily studied using optical methods. The electron spectrometers are excellent lab-based tools for student training in instrumentation and science.