# # arev:/usr/local/unicat/unireq/beamreq/req00043.txt # UNICAT Member Beam Time Request #43 # created Tue Jan 05 13:12:34 CST 1999 # days: 6 description: Two planned experiments: 1. Temperature dependent TDS patterns of superconducting oxides. The scattered pictures will resolve phonon structure and population over a wide momentum spectrum. The intended temperature range is from above to well below the superconducting transition temperature. Significant phonon coupling to electron pairs and the subsequent dispersion shift is predicted, and as yet unobserved. This experiment requires a refrigerating displex with one wide-range Be window. For a sample of BCCO[2212], Tc~82K so the target low temperature is ~40K. If this is successful, we have available Mg-Al2-O4 and lead-oxides for further study. 2. Low temperature TDS patterns of silicon along high-symmetry directions (Si[100] Si[111]). This is part of an ongoing experiment establishing phonon dispersion curves from TDS. The low temperature should limit population to the main aucoustic branches. When this picture is analyzed with previous high temperature data, a unique solution for the relevant theoretical parameters is established. equipment+required: 33-ID-D hutch. Displex required, large subtended angle Be windows desired on shroud but not absolutely necessary. Image plates. experiment: Temperature dependent TDS images of superconducting oxides hazards: No special procedures needed. All samples are in solid form and are stable in air. Do not ingest or inhale. name: T. C. Chiang new+request: on nonmembers: Zhongming Wu, Martin Holt station: 33ID-D unacceptable+dates: #QUERY_STRING: #REMOTE_HOST: chiang9.mrl.uiuc.edu #REMOTE_ADDR: 128.174.103.151 #CONTENT_LENGTH: 1678 #HTTP_REFERER: http://www.uni.aps.anl.gov/unireq.htm #HTTP_USER_AGENT: Mozilla/4.04 [en] (Win95; I ;Nav)