Development of a linac-based LEPD experimental station for surface structure analysis and coordination with synchrotron radiation ARPES
Authors:
Rezwan Ahmed,
Izumi Mochizuki,
Toshio Hyodo,
Tetsuroh Shirasawa,
Seigi Mizuno,
Yoshinari Kondo,
Kenichi Ozawa,
Miho Kitamura,
Kenta Amemiya,
Bartlomiej Checinski,
Jozef Ociepa,
Achim Czasch,
Ottmar Jagutzki,
Ken Wada
Abstract:
We report on the development of a low-energy positron diffraction (LEPD) experimental station for surface structure analysis using a linac-based slow-positron beam. LEPD, the positron counterpart of low-energy electron diffraction (LEED), offers higher accuracy in surface structure determination. The station enables acquisition of LEPD I-V curves within a few hours, allowing measurements before su…
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We report on the development of a low-energy positron diffraction (LEPD) experimental station for surface structure analysis using a linac-based slow-positron beam. LEPD, the positron counterpart of low-energy electron diffraction (LEED), offers higher accuracy in surface structure determination. The station enables acquisition of LEPD I-V curves within a few hours, allowing measurements before surface degradation occurs. It consists of two ultra-high vacuum (UHV) chambers: one for sample preparation and the other for LEPD observations. The preparation chamber includes an Ar+ sputtering system, a triple-pocket electron beam evaporator, three gas introduction systems, additional user-configurable ports, and a LEED/Auger electron spectroscopy (AES) system. Sample manipulators enable rapid cooling, precise positioning, and orientation adjustments. In the preparation chamber, the manipulator also supports direct current heating up to 1200 °C. The sample holder is compatible with the LEPD station at SPF-A4 and the ARPES station at PF BL-13B, both located at the Tsukuba campus of the Institute of Materials Structure Science (IMSS), KEK. Design concepts and experimental demonstrations are presented.
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Submitted 3 January, 2025; v1 submitted 30 December, 2024;
originally announced January 2025.