Cleaning of the inner surface for Separated-type Drift Tube Linac with Dilute Hydrochloric Acid

Arai, Sora; Kosaka, Satoshi*; Nemoto, Yasuo*; Kitamura, Ryo

JAEA-Technology 2023-009, 18 Pages, 2023/05

JAEA-Technology-2023-009.pdf:1.89MB

The linac located at the head of the J-PARC accelerators and required to provide the stable and high-quality beam. One of the accelerating cavities in the linac is the Separated-type Drift Tube Linac (SDTL). It is important to appropriately apply the RF power into the cavity for the stable operation. However, after the recovery from the Great East Japan Earthquake, the RF power could not be applied into the cavities for several SDTL cavities because the voltage standing wave ratio increased around the designed operating power. The investigation revealed that the inner surface of the cavity was exposed to high humidity and the backflow of oil from the rotary pump for a long period of time after the earthquake. It was suggested that the residue on the inner surface caused the multipactor resulted in the failure when the power was applied. The residue was wiped out with organic solvents and acids, resulted in solving the failure. This report describes the method and results of the cleaning for the cavity in 2021.

Oxygen reduction activity and interfacial structures of LaSrCoO at initial electrochemical process in an alkaline solution

Matsuzaki, Akira*; Hirayama, Masaaki*; Oguchi, Shoya*; Komo, Mamoru*; Ikezawa, Atsunori*; Suzuki, Kota*; Tamura, Kazuhisa; Arai, Hajime*; Kanno, Ryoji*

Electrochemistry (Internet), 90(10), p.107001_1 - 107001_8, 2022/10

https://doi.org/10.5796/electrochemistry.22-00079

Oxygen reduction and evolution reactions (ORR and OER) of perovskite-type LaSrCoO were characterized using two-dimensional model electrodes with different reaction planes. Synthesized by pulsed laser deposition, these thin and flat electrodes can reveal the reaction plane dependence of the ORR activity. From steady-state polarization measurements in KOH (aq.), the ORR activity was the highest on the (001) film during the first ORR/OER cycle, and it decreased significantly during the second cycle. In-situ synchrotron X-ray diffraction clarified crystal structure changes in the bulk and surface regions of LaSrCoO, and these changes are associated with forming oxygen defects during the initial electrochemical process. Furthermore, the LaSrCoO surface partially decomposed upon reacting. Therefore, the interfacial structures formed in the electrochemical reaction field is important for enhancing ORR and OER activities.

Spin excitations coupled with lattice and charge dynamics in LaSrCuO

Ikeuchi, Kazuhiko*; Wakimoto, Shuichi; Fujita, Masaki*; Fukuda, Tatsuo; Kajimoto, Ryoichi; Arai, Masatoshi*

Physical Review B, 105(1), p.014508_1 - 014508_7, 2022/01

https://doi.org/10.1103/PhysRevB.105.014508

Devil's staircase transition of the electronic structures in CeSb

Kuroda, Kenta*; Arai, Yosuke*; Rezaei, N.*; Kunisada, So*; Sakuragi, Shunsuke*; Alaei, M.*; Kinoshita, Yuto*; Bareille, C.*; Noguchi, Ryo*; Nakayama, Mitsuhiro*; et al.

Nature Communications (Internet), 11, p.2888_1 - 2888_9, 2020/06

https://doi.org/10.1038/s41467-020-16707-6

Q dependence of magnetic resonance mode on FeTeSe studied by inelastic neutron scattering

Ishikado, Motoyuki*; Kodama, Katsuaki; Kajimoto, Ryoichi; Nakamura, Mitsutaka; Inamura, Yasuhiro; Ikeuchi, Kazuhiko*; Ji, S.*; Arai, Masatoshi*; Shamoto, Shinichi

Condensed Matter (Internet), 4(3), p.69_1 - 69_10, 2019/09

https://doi.org/10.3390/condmat4030069

The enhancement magnetic resonance mode of FeTeSe is limited around Q = (, 0). Q dependence is found to be consistent with a theoretical simulation of the magnetic resonance mode with the sign-reversing order parameter of swave.

Lithium intercalation and structural changes at the LiCoO surface under high voltage battery operation

Taminato, So*; Hirayama, Masaaki*; Suzuki, Kota*; Tamura, Kazuhisa; Minato, Taketoshi*; Arai, Hajime*; Uchimoto, Yoshiharu*; Ogumi, Zempachi*; Kanno, Ryoji*

Journal of Power Sources, 307, p.599 - 603, 2016/03

https://doi.org/10.1016/j.jpowsour.2015.12.133

An epitaxial-film model electrode of LiCoO(104) was fabricated on SrRuO(100)/Nb:SrTiO(100) using pulsed laser deposition. The 50 nm thick LiCoO(104) film exhibited lithium (de-)intercalation activity with a first discharge capacity of 119 mAh g between 3.0 and 4.4 V, followed by a gradual capacity fading with subsequent charge-discharge cycles. In contrast, a 3.2 nm thick LiPO-coated film exhibited a higher intercalation capacity of 148 mAh g with superior cycle retention than the uncoated film. In situ surface X-ray diffraction measurements revealed a small lattice change at the coated surface during the (de-)intercalation processes compared to the uncoated surface. The surface modification of LiCoO by the LiPO coating could lead to improvement of the structural stability at the surface region during lithium (de-)intercalation at high voltage.

MAGIC chopper; Basic concept and experimental evaluation

Nakamura, Mitsutaka; Ikeuchi, Kazuhiko*; Kajimoto, Ryoichi; Kambara, Wataru; Krist, T.*; Shinohara, Takenao; Arai, Masatoshi; Iida, Kazuki*; Kamazawa, Kazuya*; Inamura, Yasuhiro; et al.

JAEA-Conf 2015-002, p.339 - 348, 2016/02

https://doi.org/10.11484/jaea-conf-2015-002

We have developed a new Fermi chopper referred to as Magic chopper to realize the full optimization of the experimental condition for Multi-Ei method in a chopper spectrometer. In this study, the theoretical aspects of MAGIC chopper concept will be initially presented, and the performances of MAGIC chopper will be evaluated by both Monte Carlo simulation and neutron transmission experiment.

SENJU; A New time-of-flight single-crystal neutron diffractometer at J-PARC

Ohara, Takashi; Kiyanagi, Ryoji; Oikawa, Kenichi; Kaneko, Koji; Kawasaki, Takuro; Tamura, Itaru; Nakao, Akiko*; Hanashima, Takayasu*; Munakata, Koji*; Moyoshi, Taketo*; et al.

Journal of Applied Crystallography, 49(1), p.120 - 127, 2016/02

https://doi.org/10.1107/S1600576715022943

Background caused by continuously emitted high-energy neutrons at the chopper spectrometer 4SEASONS

Kajimoto, Ryoichi; Nakamura, Mitsutaka; Inamura, Yasuhiro; Kamazawa, Kazuya*; Ikeuchi, Kazuhiko*; Iida, Kazuki*; Ishikado, Motoyuki*; Nakajima, Kenji; Harada, Masahide; Arai, Masatoshi

JPS Conference Proceedings (Internet), 8, p.036001_1 - 036001_6, 2015/09

https://doi.org/10.7566/JPSCP.8.036001

Nucleoside diphosphate kinase from psychrophilic sp. AS-131 isolated from Antarctic Ocean

Yonezawa, Yasushi*; Nagayama, Aiko*; Tokunaga, Hiroko*; Ishibashi, Matsujiro*; Arai, Shigeki; Kuroki, Ryota; Watanabe, Keiichi*; Arakawa, Tsutomu*; Tokunaga, Masao*

Protein Journal, 34(4), p.275 - 283, 2015/08

https://doi.org/10.1007/s10930-015-9623-0

Nucleoside diphosphate kinase isolated from psychrophilic sp. AS-131 (ASNDK) was expressed in and purified to homogeneity. Comparing to mesophilic NDK isolated from , ASNDK exhibited highly elevated thermolability: (1) expression at 37C as a denatured insoluble form, and (2) 30C lower optimum temperature of enzymatic activity. The subunit structure of ASNDK was suggested to be dimer, as in NDKs isolated from moderate halophiles.