|Budget Amount *help
¥16,200,000 (Direct Cost : ¥16,200,000)
Fiscal Year 1992 : ¥5,200,000 (Direct Cost : ¥5,200,000)
Fiscal Year 1991 : ¥11,000,000 (Direct Cost : ¥11,000,000)
As a surface analysis technique, a Reflection High Energy Electron Diffraction (RHEED) technique has been successfully used. In the present project, the investigator aimed to develop a Reflection High Energy Positron Diffraction (RHEPD) technique for the first time. As compared with RHEED, RHEPD is superior in the following points; low multiple scattering, no exchange interaction, nearly zero inner potential and so on.
In this project, the investigator manufactured trially a Reflection High Energy Positron Diffractometer for the first time in the world. In FY1991, the installation of vacuum systems for the diffractometer, the brightness enhancement of the monoenergetic positron beam, the acceleration of positrons up to 50 keV and so on have been completed. In FYI1992, the operation of ultra high vacuum systems was successfully conducted and a new and high efficient positron moderator composed of a W film and A Si wafer has been developed. The computer program for the data aquisition of two dimensional images of RHEPD patterns has been developed. As a result, the accumulation of two dimensional data in real time has been possible. As the first target of the RHEPD experiment, we selected the Se-coated GaAs(100) surface. At present, the 2 X 1 structure was observed after heating at 550ﾟC. The high statistic RHEPD data are now being accumulated. During the two years research , the basis for the REPD spectrometer has been constructed.