Pulsed muon facility of J-PARC MUSE

Shimomura, Koichiro*; Koda, Akihiro*; Pant, A. D.*; Sunagawa, Hikaru*; Fujimori, Hiroshi*; Umegaki, Izumi*; Nakamura, Jumpei*; Fujihara, Masayoshi; Tampo, Motonobu*; Kawamura, Naritoshi*; et al.

Interactions (Internet), 245(1), p.31_1 - 31_6, 2024/12

https://doi.org/10.1007/s10751-024-01863-8

Watershed-geochemical model to simulate dissolved and particulate Cs discharge from a forested catchment

Sakuma, Kazuyuki; Hayashi, Seiji*; Yoshimura, Kazuya; Kurikami, Hiroshi; Malins, A.; Funaki, Hironori; Tsuji, Hideki*; Kobayashi, Takamaru*; Kitamura, Akihiro; Iijima, Kazuki

Water Resources Research, 58(8), p.e2021WR031181_1 - e2021WR031181_16, 2022/08

https://doi.org/10.1029/2021WR031181

Hydrogen absorption and diffusion behaviors in cube-shaped palladium nanoparticles revealed by ambient-pressure X-ray photoelectron spectroscopy

Tang, J.*; Seo, O.*; Rivera Rocabado, D. S.*; Koitaya, Takanori*; Yamamoto, Susumu*; Namba, Yusuke*; Song, C.*; Kim, J.*; Yoshigoe, Akitaka; Koyama, Michihisa*; et al.

Applied Surface Science, 587, p.152797_1 - 152797_8, 2022/06

https://doi.org/10.1016/j.apsusc.2022.152797

The hydrogen absorption and diffusion mechanisms on cube-shaped Pd nanoparticles (NPs) which are important hydrogen-storage materials were studied using X-ray photoelectron spectroscopy and DFT calculations. In the surface region, hydrogen absorption showed almost similar behavior regardless of the NPs size. It was found that the octahedral sites are more favorable than the tetrahedral sites for hydrogen occupation. We also clarified that the hydrogen atoms absorbing on the smaller-sized Pd NPs diffuse to the subsurface more actively because of the weakened Pd-H bond by the surface disordering, which plays an important role in hydrogen adsorption at a low H pressure.

Radiological estimation and validation for the Accelerator-Based Boron Neutron Capture Therapy Facility at the Ibaraki Neutron Medical Research Center

Nakashima, Hiroshi; Nakamura, Takemi; Kobayashi, Hitoshi*; Tanaka, Susumu*; Kumada, Hiroaki*

NEA/NSC/R(2021)2 (Internet), p.142 - 151, 2021/12

Aiming of development of facilities for boron neutron capture therapy (BNCT) that can be installed in hospitals, an accelerator-based BNCT facility is being developed at the Ibaraki Neutron Medical Research Center under a collaboration among the Japan Atomic Energy Agency, the High Energy Accelerator Research Organization, the University of Tsukuba, and other institutions. It consists of a proton accelerator, having a maximum beam power of 80 kW, and a target, moderator, collimator and shield (TMCS) system. For the design concept, to satisfy the BNCT beam conditions and achieve a low activation, the radiation behavior in the TMCS system was simulated by the Monte Carlo method and this system configuration was optimized accordingly. In addition, the radiation estimation of the TMCS system was verified via several experiments and its applicability for BNCT was proved. This report reviews the estimation and validation studies for the development of the accelerator-based BNCT facility.

Position dependency of the scattered intensity in the time-of-flight backscattering spectrometer DNA

Matsuura, Masato*; Yamada, Takeshi*; Tominaga, Taiki*; Kobayashi, Makoto*; Nakagawa, Hiroshi; Kawakita, Yukinobu

JPS Conference Proceedings (Internet), 33, p.011068_1 - 011068_6, 2021/03

https://doi.org/10.7566/JPSCP.33.011068

The position dependence of the scattered intensity in the time-of-flight backscattering spectrometer DNA was investigated. A periodic structure for both vertical (pixel) and horizontal (PSD) directions was observed. The solar slit and over-bending of an analyzer crystal is discussed as a possible origin of the modulation in the intensity. We have developed software program for the systematic correction of the position-dependent intensity and offset energy for the elastic peak. This corrects the deviation from the true scattering intensity and improve the quality of the data, which includes the energy resolution.

How different is the core of F from O ?

Tang, T. L.*; Uesaka, Tomohiro*; Kawase, Shoichiro; Beaumel, D.*; Dozono, Masanori*; Fujii, Toshihiko*; Fukuda, Naoki*; Fukunaga, Taku*; Galindo-Uribarri, A.*; Hwang, S. H.*; et al.

Physical Review Letters, 124(21), p.212502_1 - 212502_6, 2020/05

https://doi.org/10.1103/PhysRevLett.124.212502

The structure of a neutron-rich F nucleus is investigated by a quasifree () knockout reaction. The sum of spectroscopic factors of orbital is found to be 1.0 0.3. The result shows that the O core of F nucleus significantly differs from a free O nucleus, and the core consists of 35% O, and 65% excited O. The result shows that the O core of F nucleus significantly differs from a free O nucleus. The result may infer that the addition of the proton considerably changes the neutron structure in F from that in O, which could be a possible mechanism responsible for the oxygen dripline anomaly.

Development of a structured overset Navier-Stokes solver with a moving grid and full multigrid method

Ohashi, Kunihide*; Hino, Takanori*; Kobayashi, Hiroshi*; Onodera, Naoyuki; Sakamoto, Nobuaki*

Journal of Marine Science and Technology, 24(3), p.884 - 901, 2019/09

https://doi.org/10.1007/s00773-018-0594-7

An unsteady Reynolds averaged Navier-Stokes solver with a structured overset grid method has been developed. Velocity pressure coupling is achieved using an artificial compressibility approach, spatial discretization is based on a FVM. Body motions are considered using the grid deformation technique and grid velocities in the convective term. The full multigrid (FMG) method is applied to obtain fast convergence. The cell flag on a coarse grid level is determined using the cell flag on a fine grid level. In the coarse and fine grid level calculations at the FMG stage, the data are interpolated until the finest grid level is achieved at an overset update interval. Then, the data are updated based on the overset relations at the finest grid level and then transferred to a coarser grid level. The computations for flows around a hull form, including an unsteady simulation with regular waves, are demonstrated.

Progress of general control system for Materials and Life Science Experimental Facility at J-PARC

Sakai, Kenji; Oi, Motoki; Takada, Hiroshi; Kai, Tetsuya; Nakatani, Takeshi; Kobayashi, Yasuo*; Watanabe, Akihiko*

JAEA-Technology 2018-011, 57 Pages, 2019/01

JAEA-Technology-2018-011.pdf:4.98MB

For safely and efficiently operating a spallation neutron source and a muon target, a general control system (GCS) operates within Materials and Life Science Experimental Facility (MLF). GCS administers operation processes and interlocks of many instruments. It consists of several subsystems such as an integral control system (ICS), interlock systems (ILS), shared servers, network system, and timing distribution system (TDS). Although GCS is an independent system that controls the target stations, it works closely with the control systems of the accelerators and other facilities in J-PARC. Since the first beam injection, GCS has operated stably without any serious troubles after modification based on commissioning for operation and control. Then, significant improvements in GCS such as upgrade of ICS by changing its framework software and function enhancement of ILS were proceeded until 2015. In this way, many modifications have been proceeded in the entire GCS during a period of approximately ten years after start of beam operation. Under these situation, it is important to comprehend upgrade history and present status of GCS in order to decide its upgrade plan. This report summarizes outline, structure, roles and functions of GCS in 2017.

Introduction to radiation physics; Third revised edition

Tada, Junichiro*; Nakashima, Hiroshi; Hayano, Ryugo*; Kobayashi, Hitoshi*; Asano, Yoshihiro*

Wakariyasui Hoshasen Butsurigaku; Kaitei 3-Han, 305 Pages, 2018/03

This book is an introduction to radiation physics. Under the concept of "linking physics of high school and radiation physics" for readers with high school graduation degree, we are doing simple commentary on the basis of qualitative explanation as much as possible. This book begins with "What is Radiation Physics", and consists of 12 chapters, including introductory special relativity, introductory quantum theory, structures of atoms and nuclei, radiations, radioactivity, interactions between radiation and matter, accelerators, radiation dose and so on.

Chemical form analysis of reaction products in Cs-adsorption on stainless steel by means of HAXPES and SEM/EDX

Kobata, Masaaki; Okane, Tetsuo; Nakajima, Kunihisa; Suzuki, Eriko; Owada, Kenji; Kobayashi, Keisuke*; Yamagami, Hiroshi; Osaka, Masahiko

Journal of Nuclear Materials, 498, p.387 - 394, 2018/01

https://doi.org/10.1016/j.jnucmat.2017.10.035

In this study, for the understandings of Cesium (Cs) adsorption behavior on structure materials in severe accidents at a light water nuclear reactor, the chemical state of Cs and its distribution on the surface of SUS304 stainless steel (SS) with different Si concentration were investigated by hard X-ray photoelectron spectroscopy (HAXPES) and scanning electron microscope / energy dispersive X-ray spectroscopy (SEM/EDX). As a result, it was found that Cs is selectively adsorbed at the site where Si distributes with high concentration. CsFeSiO is a dominant Cs products in the case of low Si content, mainly formed, while CsSiO and CsSiO are formed in addition to CsFeSiO in the case of high Si content. The chemical forms of the Cs compounds produced in the adsorption process on the SS surface has a close correlation with the concentration and chemical states of Si originally included in SS.