Observation of longitudinal magnetic fluctuations at a first-order ferromagnetic quantum phase transition in UGe

Noma, Yuichiro*; Kotegawa, Hisashi*; Kubo, Tetsuro*; To, Hideki*; Harima, Hisatomo*; Haga, Yoshinori; Yamamoto, Etsuji; Onuki, Yoshichika*; Ito, Kohei*; Nakamura, Ai*; et al.

Journal of the Physical Society of Japan, 90(7), p.073707_1 - 073707_5, 2021/07

https://doi.org/10.7566/JPSJ.90.073707

Upgrade of the 3-MeV linac for testing of accelerator components at J-PARC

Kondo, Yasuhiro; Hirano, Koichiro; Ito, Takashi; Kikuzawa, Nobuhiro; Kitamura, Ryo; Morishita, Takatoshi; Oguri, Hidetomo; Okoshi, Kiyonori; Shinozaki, Shinichi; Shinto, Katsuhiro; et al.

Journal of Physics; Conference Series, 1350, p.012077_1 - 012077_7, 2019/12

https://doi.org/10.1088/1742-6596/1350/1/012077

We have upgraded a 3-MeV linac at J-PARC. The ion source is same as the J-PARC linac's, and the old 30-mA RFQ is replaced by a spare 50-mA RFQ, therefore, the beam energy is 3 MeV and the nominal beam current is 50 mA. The main purpose of this system is to test the spare RFQ, but also used for testing of various components required in order to keep the stable operation of the J-PARC accelerator. The accelerator has been already commissioned, and measurement programs have been started. In this paper, present status of this 3-MeV linac is presented.

Development of cement based encapsulation for low radioactive liquid waste in Tokai Reprocessing Plant

Matsushima, Ryotatsu; Sato, Fuminori; Saito, Yasuo; Atarashi, Daiki*

Proceedings of 3rd International Symposium on Cement-based Materials for Nuclear Wastes (NUWCEM 2018) (USB Flash Drive), 4 Pages, 2018/10

At TRP, LWTF was constructed as a facility for processing low radioactive liquid waste and solid waste generated at TRP, and a cold test is been carrying out. In this facility, initially, nitrate waste liquid after separation of nuclides generated with treatment of low radioactive liquid waste was to be solidified by using borate. However, at present, it is necessary to decompose the nitrate in the liquid waste to reduce the environmental burden. For the reason, as a plan to replace the nitrate with the carbonate and to make it as a cement based encapsulation, we are studying for the introduction of the facility. Currently, as a cement solidification technology development for this liquid waste, we are studying the application of cement material based on blast furnace slag (BFS) as a main component. In this report, we show the results of the test conducted on the actual scale (200 L drum can scale).

Study on hydrogen generation from cement solidified products loading low-radioactive liquid wastes at Tokai Reprocessing Plant

Ito, Yoshiyuki; Matsushima, Ryotatsu; Sato, Fuminori

QST-M-8; QST Takasaki Annual Report 2016, P. 69, 2018/03

https://repo.qst.go.jp/records/73811

no abstracts in English

Self-radiation effects and glassy nature of magnetic transition in AmO revealed by O-NMR

Tokunaga, Yo; Nishi, Tsuyoshi; Nakada, Masami; Ito, Akinori*; Sakai, Hironori; Kambe, Shinsaku; Homma, Yoshiya*; Honda, Fuminori*; Aoki, Dai*; Walstedt, R. E.*

Physical Review B, 89(21), p.214416_1 - 214416_8, 2014/06

https://doi.org/10.1103/PhysRevB.89.214416

The magnetic phase transition near K in AmO has been investigated microscopically by means of O NMR. To avoid complexities arising from sample aging associated with the alpha decay of Am, all measurements have been performed within 40 days after sample synthesis. Even during such a short period, however, a rapid change of NMR line shape has been observed at 1.5 K, suggesting that the ground state of AmO is very sensitive to disorder. We have also confirmed the loss of O NMR signal intensity over a wide temperature range below , and more than half of oxygen nuclei are undetectable at 1.5 K. This behavior reveals the persistence of slow and distributed spin fluctuations down to temperatures well below . In the paramagnetic state, strong NMR line broadening and spatially inhomogeneous spin fluctuations have been observed. The results are all indicative of short-range, spin-glass-like character for the magnetic transition in this system.

Reactions of free positrons in low temperature polyethylene; Delayed Ps formation and positron localization

Hirade, Tetsuya; Suzuki, Naoki*; Saito, Fuminori*; Hyodo, Toshio*

Physica Status Solidi (C), 4(10), p.3714 - 3717, 2007/09

https://doi.org/10.1002/pssc.200675742

Positronium (Ps) can be formed by a reaction of trapped electrons and free positrons at low temperatures in molecular solids. While Ps formation by Ore and spur process must be fast, Ps formation by trapped electrons and free positrons is possible even at later positron age. The evidence of this delayed Ps formation was obtained by age-momentum correlation measurement of electron-positron pair annihilation -rays. In this work the parameter curves measured with trapped electrons and no trapped electrons in polyethylene are interpreted by introducing possible positron reactions. Positrons that escape from Ps formation by the Ore and the spur processes have chance to form Ps with trapped electrons. This Ps formation competes with the positron localization resulting from the trapping between molecules or the weakly binding on molecules, ions, or radicals. Assuming the possibility of both the delayed Ps formation and delayed positron trapping and that S-parameters for ortho-Ps and free positrons are the same, we obtain a good fit to the observed time dependent S-parameter curves .

Divertor biasing effects to reduce L/H power threshold in the JFT-2M tokamak

Miura, Yukitoshi; *; *; Hoshino, Katsumichi; *; *; Kasai, Satoshi; Kawakami, Tomohide; Kawashima, Hisato; Maeda, M.*; et al.

Fusion Energy 1996, p.167 - 175, 1997/05

no abstracts in English

Ion heat pulse after a sawtooth crash in the JAERI Fusion Torus-2M tokamak

Miura, Yukitoshi; Okano, Fuminori; Suzuki, Norio; Mori, Masahiro; Hoshino, Katsumichi; Takizuka, Tomonori; JFT-2M Group; Ito, Kimitaka*; Ito, Sanae*

Physics of Plasmas, 3(10), p.3696 - 3700, 1996/10

https://doi.org/10.1063/1.872029

no abstracts in English

Ion heat pulse after sawtooth crash in the JFT-2M tokamak

Miura, Yukitoshi; Okano, Fuminori; Suzuki, Norio; Mori, Masahiro; Hoshino, Katsumichi; Maeda, Hikosuke; Takizuka, Tomonori; JFT-2M Group; Ito, Kimitaka; Ito, Sanae*

NIFS-240, 14 Pages, 1993/08

no abstracts in English

Rapid change of hydrogen neutral energy distribution at L/H-transition in JFT-2M H-mode

Miura, Yukitoshi; Okano, Fuminori; Suzuki, Norio; Mori, Masahiro; Hoshino, Katsumichi; Maeda, Hikosuke; Takizuka, Tomonori; JFT-2M Group; Ito, Sanae*; Ito, Kimitaka

NIFS-134, 20 Pages, 1992/02

no abstracts in English