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Fukaya, Yuki
no journal, ,
no abstracts in English
Suzuki, Seiya; Katsube, Daiki*; Yano, Masahiro; Tsuda, Yasutaka; Terasawa, Tomoo; Asaoka, Hidehito; Yuhara, Junji*; Yoshigoe, Akitaka
no journal, ,
Germanene is a two-dimensional (2D) sheet of germanium (Ge) with a honeycomb lattice. Recent theoretical studies have predicted several interesting electronic properties of germanene, such as 2D topological insulators. However, unlike graphene, germanene is easily oxidized in air, making it difficult to realize electrical devices based on germanene. To overcome the drawback of the chemical stability of germanene, it is necessary to understand how germanene is oxidized. Therefore, we started to study germanene and discovered an interesting phenomenon: oxidized germanene can be restored to good quality germanene simply by heating it in ultra-high vacuum (UHV). X-ray photoelectron spectroscopy spectra and low energy electron diffraction patterns indicate that the oxidized germanene is fully recovered after heating at 500 degrees Celsius. The detailed mechanism of the recovery will be discussed in the presentation.
Kobayashi, Fuminori; Kamiya, Junichiro; Takahashi, Hiroki; Suzuki, Yasuo*; Tasaki, Ryuta*
no journal, ,
The vacuum equipment in the L3BT beamline of J-PARC LINAC is controlled by the vacuum system in each area divided by beamline gate valves (BLGVs). In the past, the vacuum system controlled the vacuum equipment by area between BLGVs and did not monitor information about the equipment or vacuum pressure between each other. As a result, equipment can be operated regardless of conditions in adjacent areas, causing problems such as sudden deterioration of vacuum pressure in high vacuum areas and equipment failure due to atmospheric inrushes into vacuum equipment in operation. In addition, since all BLGVs are designed to close simultaneously when an interlock (ILK) occurs due to pressure deterioration, BLGVs in areas unaffected by vacuum deterioration are also forced to close. It is necessary to take measures to make BLGVs operate more appropriately in terms of the number of open/close limits and wear. To solve these various problems, it is first necessary to eliminate human error and increase safety by making it possible to monitor information on equipment and vacuum pressure between areas. Furthermore, it is necessary to improve maintainability by automatically controlling each BLGV individually. Therefore, we have modified and constructed the vacuum system control system with the aim of realizing safe and efficient maintenance and operation of the L3BT vacuum system.
H
OH liquid target in an ultra-high vacuumOgiwara, Norio*; Yamamoto, Kazami; Kuramochi, Masaya*
no journal, ,
An ultra-high vacuum compatible ethanol liquid target is being developed to investigate the reaction products produced by the interaction of a high intensity laser with ethanol. One of the issues to be solved is the need to maintain an ultra-high vacuum in the main chamber for analysis within ~1 m of the liquid target generator, where the reaction chamber containing the generator is planned to be operated about 10 Pa or less. The constraint is to have a straight-through section without obstructions, so that reaction products can fly into the main chamber from the vicinity of the liquid target. In this development, this straight-through section is a cylinder with a diameter of 20 mm, as shown in Fig. 1. We attempted to solve the above problem by installing an in-line liquid nitrogen trap between the reaction chamber and the main chamber and improving the trap.
Kamiya, Junichiro; Abe, Kazuhide; Kobata, Masaaki; Tsuda, Yasutaka; Fukuda, Tatsuo; Fujimori, Shinichi; Morohashi, Yuko; Yamada, Ippei; Yoshigoe, Akitaka
no journal, ,
Sequence measurements with XPS have been performed to understand more detail about the activation and deterioration mechanism. The sample of a titanium plate with Ti-Zr-V coating of 1 um thickness was prepared. The sample was set in the surface science station in the BL23SU of SPring-8. At first, the XPS measurements for the sample surface were performed during the sample temperature was raised to 250
C. After that, the XPS was subsequently performed during the injection of oxygen gas into the chamber while keeping the sample temperature at 250C, which corresponds to the accelerated deterioration test. After that, the depth profile of the sample was measured with another XPS apparatus with an X-ray tube by argon etching. The result showed that the surface Zr gets the oxygen from Ti oxide and V oxide at the first stage of the activation and the oxygen of the Zr oxide would diffuse to the bulk in the continuous temperature rise. It was revealed that the concentrated oxygen in the coating exists in the forms of mainly Zr oxide and Ti oxide in the second place.