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In
( = Co, Rh, Ir)Kurihara, Ryosuke*; Hirose, Yusuke; Matsui, Kazuki*; Miyake, Atsushi*; Tsunoda, Ryoma*; Kondo, Masaki*; Settai, Rikio*; Akatsu, Mitsuhiro*; Nemoto, Yuichi*; Yaguchi, Hiroshi*; et al.
JJAP Conference Proceedings (Internet), 12, p.011006_1 - 011006_6, 2026/02
no abstracts in English
Hirade, Tetsuya; Furuta, Hikaru*; Torikai, Yuji*; Fujimura, Yuki; Michishio, Koji*
JJAP Conference Proceedings (Internet), 9, p.011106_1 - 011106_7, 2023/00
Positron annihilation lifetime (PAL) measurements by use of a positron source of 
Na were performed for polycrystalline ITER-grade tungsten samples exposed to low-energy deuterium plasma. The energy of deuterium plasma was low and then it was expected that it would affect just near-surface region. However, we obtained the longer mean positron annihilation lifetime in the tungsten samples exposed to the low-energy deuterium plasma than the virgin tungsten samples. Moreover, almost same longer values were obtained even on the other (no exposed) side of the samples, although the thickness of the samples were about 2 mm. Although, there has been no report of observation of defect formation by existence of hydrogen or deuterium in tungsten, the results indicated that deuterium existence in tungsten can be one of reasons of defects formation.
Okutsu, Kenichi*; Yamashita, Takuma*; Kino, Yasushi*; Miyashita, Konan*; Yasuda, Kazuhiro*; Oka, Toshitaka; Okada, Shinji*; Sato, Motoyasu*
JJAP Conference Proceedings (Internet), 9, p.011003_1 - 011003_7, 2023/00
Muon catalyzed fusion (
CF) is a cyclic reaction where a negatively charged muon itself acts like a catalyst of nuclear fusion between hydrogen isotopes. In the CF reaction, muon transfer from deuteron to triton and muonic molecular formation are rate-limiting processes. In this work, we have investigated the role of resonance states of muonic molecule in the CF which affects the muonic deuterium atom population. Solving simultaneous rate equations numerically by the fourth-order Runge-Kutta method, we determined the muonic molecular formation rate so that the number of fusion events reproduces a latest experimental result. It is revealed that the resonance states play a role to enhance the fusion rate by accelerating the de-excitation of the muonic atoms.
Hirade, Tetsuya
JJAP Conference Proceedings (Internet), 2, p.011003_1 - 011003_6, 2014/11
Ps has negative work function in insulating materials and the repulsion between Ps and surrounding molecules can form a bubble in liquids. However, it is needed to lose energy to be in a stable bubble state. Therefore the oscillation of the bubble size is expected. The ortho-Ps pick off annihilation probability depends on the size of the Ps bubble and hence the oscillation on the lifetime spectra is expected. In the case of usual liquids, bubble formation time is not so slow and then the oscillation can not be observed by the positron annihilation lifetime measurements with the time resolution of about 200 ps. Now the bubble formation in IL is slow and then the expected oscillation on the lifetime spectra was successfully observed.
Maekawa, Masaki; Zhang, H.; Li, H.; Fukaya, Yuki; Kawasuso, Atsuo
JJAP Conference Proceedings (Internet), 2, p.011305_1 - 011305_7, 2014/11
