#################################################### # Ian Robinson # requesting 6 days, at minimum=4 days # beamline 33ID, "Surface melting of Pb nonparticles" #################################################### # top:/home/www/beamtime-requests/req00276.txt # UNICAT Member Beam Time Request #276 # created Tue Aug 20 12:30:14 CDT 2002 #################################################### beamline: 33ID collaboration: No collaborator+Hawoong: on contact: ikr@uiuc.edu days: 6 description: We are making steady progress with this experiment. The most recent run in Aug 2002 solved the deposition and sample preparation problems and yielded good data on spherical particles of about 500nm diameter. The ring-like fringes surrounding the diffraction was found to disappear as the temperature approached melting. The quantitative analysis of the data is now in progress. These experiments have now reached the fundamental limit that the attachment of the particles to the SiO_2 substrate become unstable at high temperatures, so they start to move around perceptibly on the time scale of 30minutes needed to measure them. To solve this problem we plan to install a KB mirror to concentrate the beam AFTER the coherence-selecting slit. This should increase the coherent flux at least 10x without broadening the diffraction pattern. We have the epics-compatible mirror positioning device ready for use on 34ID and have arranged to borrow a mirror from Peter Eng at CARS. equipment+required: UNV diffractometer in 33-ID-E experiment: Surface melting of Pb nonparticles foreign+nationals: hazards: Same safety envelope as before. minimumdays: 4 name: Ian Robinson new+request: on nonmembers: unacceptable+dates: Thanksgiving will probably be bad for Mark and Garth. October 23-27 #REMOTE_HOST: robinsonpc.mrl.uiuc.edu #REMOTE_ADDR: 130.126.102.115 #CONTENT_LENGTH: 1398 #HTTP_REFERER: http://www.uni.aps.anl.gov/unireq.htm #HTTP_USER_AGENT: Mozilla/4.7 [en] (Win95; U)