報(bào)告人： Dr. Thomas Scott Toellner

單 位：Advanced Photon Source, Argonne National Laboratory, Argonne Illinois 60439

時(shí) 間:  2011年12月12日9:00AM

地 點(diǎn)：同步輻射12號(hào)廳會(huì)議室

題 目：Research and Development for High-resolution X-ray Spectroscopies

Abstract: High-resolution X-ray spectroscopies like nuclear resonant scattering and inelastic X-ray scattering provide detailed information about atom dynamics and, through synchrotron Moessbauer spectroscopy, also gives information on the local chemical environment of a resonant isotope in a host lattice. These scattering techniques require narrow energy-band filtering of synchrotron radiation, and typically use meV-bandwidth crystal optics to perform measurements. Research and development in high energy-resolution optics has been ongoing at the Advanced Photon Source (APS) for the past two decades with the most recent progress being the implementation of cryogenic stabilization for ultra-high energy-resolution monochromatization (E/dE > 10^8) to enhance wavelength stability and produce greater efficiency. In order to go beyond the limitations of crystal optics for some applications, an alternative approach to narrow energy-band filtering is under development that uses a high-speed shutter to extract a 10-neV-bandwidth X-ray beam for Moessbauer spectroscopy. This offers significant potential for extending the capabilities of synchrotron Moessbauer spectroscopy. Optics and methodology developments relevant to applications of high-resolution X-ray spectroscopies will be presented.

Biographical sketch:

Dr. Toellner received his Ph.D. in Physics from Northwestern University in 1996. He is currently a research physicist at the Advanced Photon Source at Argonne National Lab near Chicago, Illinois, where he develops high-precision measurement techniques involving nuclear resonant scattering of synchrotron radiation. He has an ongoing research and development program aimed at improving the state of the art in X-ray monochromatization.