University of Tennessee Physics

Dr. Tom Callcott

Professor
Ph.D., Purdue University, 1965

Office: 611 Science and Engineering Building
Phone: 865-974-8944 or 650-926-4898 (SLAC)
Fax: 865-974-7843
tcallcott@utk.edu

CONDENSED MATTER PHYSICS

Electronic states of solids: soft X-ray fluorescence and other spectroscopies

The properties of solids are determined in large measure by the distribution of electronic states in space and energy. Dr. Callcott has used many spectroscopies, including UV and angular resolved photoemission, and many types of optical spectroscopy to study these electronic energy distributions. Since 1986, most of his research has been devoted to soft x-ray fluorescence (SXF) spectroscopy, in which synchrotron x-ray sources are used to excite characteristic x-ray emission spectra.

SXF spectroscopy provides a measure of the energy distribution of valence electrons in solids and thus is a valuable means of studying the electronic bonding of solids. Because it is selective for chemical element and angular momentum states, it has particular value for the study of complex materials such as high Tc superconductors, ceramics, ternary alloy systems and other muti-component materials. Because it is a deep probe, it can be used for the study of bulk impurities and of buried structures and interfaces.

The excitation of spectra with soft x-ray photons rather than energetic electrons has many important advantages including the selective excitation of chosen core levels, the reduction of radiation damage in fragile materials, and the reduction of Bremstrahlung background radiation. Also, near x-ray thresholds, the coupling of excitation and emission processes in an electronic Raman scattering process often provides new and unique information about the low energy excited states of materials.

SXF studies are carried out on dedicated beamlines at the Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory (LBNL) and the CAMD synchrotron source at Louisiana State University (LSU) in collaboration with scientists from Tulane University, LSU, ORNL, LBNL, Lawrence Livermore National Laboratory, and the National Institute of Standards and Technology. The fluorescence spectrometers and endstations at both the ALS and CAMD beamlines were designed and built at UTK. The super bright undulator sources at the ALS make it the world's premier location for SXF spectroscopy studies requiring high intensity excitation.

Brief Vita

Professor Thomas A. Callcott earned a B.S. in Physics from Duke University in 1958, and the Ph.D. degree from Purdue University in 1965. After three years as a staff scientist at AT&T Bell Laboratories, he joined the faculty at the University of Tennessee in 1968. Since 1968, he has also held a part-time appointment in the Health Sciences Research Division at Oak Ridge National Laboratory (ORNL) and its predecessors. During leaves from the University, he has been a visiting scientist at the Universite de Dijon in France, at ORNL, and at the National Institute of Standards and Technology. He is a fellow of the American Physical Society, a recipient of the Chancellor's Award for Research, and of the R&D 100 Award for Scientific Equipment Design. He is the author or co-author of more than 100 research papers and project director for the soft x-ray spectroscopy project at the Advanced Light Source at Lawrence Berkeley National Laboratory. He is the past director of the UTK/ORNL Science Alliance, a state funded center of excellence supporting research collaborations between the University and ORNL.

Selected Publications

  1. T. A. Callcott and E. T. Arakawa, "The L(2,3) soft x-ray emission and absorption spectra of Na," Phys. Rev. B 18, 6622 (1978).
  2. T. L. Ferrell, T. A. Callcott, and R. J. Warmack, "Plasmons and Surfaces," American Scientist 73, 344 (1985).
  3. K. Osborn, T. A. Callcott, and D. L. Ederer, "Two new designs for soft x-ray spectrometers using variable-line-space gratings," Rev. of Sci. Instrum. 66, 34 (1995).
  4. J. J. Jia, T. A. Callcott, et al., "Resonant Inelastic X-ray scattering in Hexagonal Boron Nitride," Phys. Rev. Lett. 76, 4054 (1996).
  5. T. A. Callcott et al., "Applications of Soft X-ray Fluorescence Spectroscopy in Materials Science," Proc. of 1996 MRS Spring Meeting, April, 1996.