Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Kawamura, Seiko; Takahashi, Ryuta*; Ishikado, Motoyuki*; Yamauchi, Yasuhiro*; Nakamura, Masatoshi*; Ouchi, Keiichi*; Kira, Hiroshi*; Kambara, Wataru*; Aoyama, Kazuhiro*; Sakaguchi, Yoshifumi*; et al.
Journal of Neutron Research, 21(1-2), p.17 - 22, 2019/05
The Cryogenics and Magnets group in the Sample Environment team is responsible for operation of cryostats and magnets for user's experiments at the MLF in J-PARC. We have introduced a top-loading 
He cryostat, a bottom-loading 
He cryostat, a dilution refrigerator insert and a superconducting magnet. The frequency of use of them dramatically becomes higher in these two years, as the beam power and the number of proposal increase. To respond such situation, we have made efforts to enhance performance of these equipment as follows. The He cryostat originally involves an operation software for automatic initial cooling down to the base temperature and automatic re-charge of He. Recently we made an additional program for automatic temperature control with only the sorb heater. Last year, a new outer vacuum chamber of the magnet with an oscillating radial collimator (ORC) was fabricated. The data quality was drastically improved by introducing this ORC so that the magnet can be used even for the inelastic neutron scattering experiments.
Yamauchi, Kunihito; Okano, Jun; Shimada, Katsuhiro; Omori, Yoshikazu; Terakado, Tsunehisa; Matsukawa, Makoto; Koide, Yoshihiko; Kobayashi, Kazuhiro; Ikeda, Yoshitaka; Fukumoto, Masahiro; et al.
JAEA-Technology 2015-053, 36 Pages, 2016/03
JAEA-Technology-2015-053.pdf:8.33MB
The superconducting Satellite Tokamak machine "JT-60SA" under construction in Naka Fusion Institute is an international collaborative project between Japan (JA) and Europe (EU). The contributions for this project are based on the supply of components, and thus European manufacturer shall conduct the installation, commissioning and tests on Naka site. This means that Japan Atomic Energy Agency (JAEA) had a quite difficult issue to manage the works by European workers and their safety although there is no direct contract. This report describes the approaches for the work and safety managements, which were agreed with EU after the tough negotiation, and then the completed on-site works for Quench Protection Circuits (QPC) as the first experience for EU in JT-60SA project. With the help of these approaches by JAEA, the EU works for QPC were successfully completed with no accident, and a great achievement was made for both EU and JA.
Kajimoto, Ryoichi; Nakamura, Mitsutaka; Inamura, Yasuhiro; Kamazawa, Kazuya*; Ikeuchi, Kazuhiko*; Iida, Kazuki*; Ishikado, Motoyuki*; Nakajima, Kenji; Kawamura, Seiko; Nakatani, Takeshi; et al.
JAEA-Conf 2015-002, p.319 - 329, 2016/02
Sakaki, Hironao; Nishiuchi, Mamiko; Maeda, Shota; Sagisaka, Akito; Pirozhkov, A. S.; Pikuz, T.; Faenov, A.*; Ogura, Koichi; Fukami, Tomoyo; Matsukawa, Kenya*; et al.
Review of Scientific Instruments, 85(2), p.02A705_1 - 02A705_4, 2014/02
Times Cited Count：2 Percentile：11.24(Instruments & Instrumentation)High intensity laser-plasma interaction has attracted considerable interest for a number of years. The laser-plasma interaction is accompanied by generation of various charged particle beams. Results of simultaneous novel measurements of electron-induced photonuclear neutrons (photoneutron), which are a diagnostic of the laser-plasma interaction, are proposed to use for optimization of the laser-plasma ion generation. The proposed method is demonstrated by the laser irradiation with the intensity os 1
10
W/cm
on the metal foil target. The photoneutrons are measured by using NE213 liquid scintillation detectors. Heavy-ion signal is registered with the CR39 track detector simultaneously. The measured signals of the electron-induced photoneutrons are well reproduced by using the Particle and Heavy Ion Transport code System (PHITS). The results obtained provide useful approach for analyzing the various laser based ion beams.
Miyamoto, Nobuyoshi; Yamauchi, Kazuhiro*; Hasegawa, Hirokazu*; Hashimoto, Takeji; Koizumi, Satoshi
Physica B; Condensed Matter, 385-386(1), p.752 - 755, 2006/11
Times Cited Count：5 Percentile：27.22(Physics, Condensed Matter)The living anionic polymerization processes of isoprene and styrene in benzene-
initiated by 
-butyl lithium were studied by in-situ small-angle neutron scattering (SANS) and time-resolved molecular weight (
) measurement by gel permeation chromatography (GPC). In the course of the polymerization of isoprene (
= 5300 g mol
), the small angle scattering increased with the reaction time 
. The molecular weight and its time-change, determined by GPC, is crucial to quantitatively analyze time-resolved SANS measurements; we were able to determine association number 
uniquely as a function of . Upon termination of the living polymerization, SANS profile greatly changed: the scattering intensity in the intermediate 
-region (0.2 
1.0 nm) remarkably decreased, indicating disaggregation of the living ends upon the termination. Also, strong upturn in the low-q region appeared (q 0.1 nm) due to the generation of colloidal LiOH or LiO(C
H
), which are insoluble in benzene. Detailed data and analyses of isoprene and styrene systems will be given in the presentation.
Tanaka, Hirokazu; Yamauchi, Kazuhiro*; Hasegawa, Hirokazu*; Miyamoto, Nobuyoshi; Koizumi, Satoshi; Hashimoto, Takeji
Physica B; Condensed Matter, 385-386(1), p.742 - 744, 2006/11
Times Cited Count：22 Percentile：65.77(Physics, Condensed Matter)Polystyrene-block-polyisoprene were synthesized via living anionic polymerization. We have performed in-situ and real-time SANS, GPC, and UV-vis spectroscopy of the polymerization process in order to reveal the structure formation process of the block copolymers, especially the associated structures. From GPC and UV-vs spectroscopy. It is found that isoprene monomers are preferentially polymerized, and after that, styrene monomers are to be polymerized. It is also found from SANS measurements, that living polymers in the reaction solution formed the associated structures during the polymerization process. Moerover, it is also strongly suggested that in the earlier stage of polymerization, living polymers are mainly composed of polyisoprene with association number of 4, and once styrene monomers are polymerized, the association number drastically begins to decrease from 4 to 2.
-polystyreneYamauchi, Kazuhiro*; Hasegawa, Hirokazu*; Hashimoto, Takeji; Tanaka, Hirokazu; Motokawa, Ryuhei; Koizumi, Satoshi
Macromolecules, 39(13), p.4531 - 4539, 2006/06
Times Cited Count：36 Percentile：70.36(Polymer Science)no abstracts in English
Kasai, Satoshi*; Kamiya, Kensaku; Shinohara, Koji; Kawashima, Hisato; Ogawa, Hiroaki; Uehara, Kazuya; Miura, Yukitoshi; Okano, Fuminori; Suzuki, Sadaaki; Hoshino, Katsumichi; et al.
Fusion Science and Technology, 49(2), p.225 - 240, 2006/02
Times Cited Count：3 Percentile：24.11(Nuclear Science & Technology)The diagnostic system of JFT-2M has consisted of about 30 individual diagnostic instruments,which were used to study the plasma production, control, equilibrium, stability, confinement, plasma heating by NBI and/or RF (LH, ICRF, ECH) and current drive by RF. In these instruments, the motional Stark effect (MSE) polarimeter, charge exchanged recombination spectroscopy (CXRS), heavy-ion beam probe (HIBP), time of flight (TOF) neutral particle analyzer, etc. have contributed to make clear the improved mechanism of confinement such as H-mode and High Recycling Steady (HRS) H-mode, and to search the operational region of these modes.The infrared TV camera system and lost ion probe have played a very important role to investigate the heat load onto the walls due to ripple loss particles and escaping ions from core plasma, respectively.
Tsuzuki, Kazuhiro*; Kimura, Haruyuki; Kusama, Yoshinori; Sato, Masayasu; Kawashima, Hisato; Kamiya, Kensaku; Shinohara, Koji; Ogawa, Hiroaki; Uehara, Kazuya; Kurita, Genichi; et al.
Fusion Science and Technology, 49(2), p.197 - 208, 2006/02
Times Cited Count：11 Percentile：60.27(Nuclear Science & Technology)no abstracts in English
Ogawa, Hiroaki; Yamauchi, Yuji*; Tsuzuki, Kazuhiro; Kawashima, Hisato; Sato, Masayasu; Shinohara, Koji; Kamiya, Kensaku; Kasai, Satoshi; Kusama, Yoshinori; Yamaguchi, Kaoru*; et al.
Journal of Nuclear Materials, 329-333(Part1), p.678 - 682, 2004/08
Times Cited Count：4 Percentile：29.26(Materials Science, Multidisciplinary)no abstracts in English
Yamaguchi, Kaoru*; Yamauchi, Yuji*; Hirohata, Yuko*; Hino, Tomoaki*; Tsuzuki, Kazuhiro
Shinku, 46(5), p.449 - 452, 2003/05
no abstracts in English
Miyamoto, Nobuyoshi; Tanaka, Hirokazu*; Yamauchi, Kazuhiro*; Hasegawa, Hirokazu*; Hashimoto, Takeji; Koizumi, Satoshi
no journal, ,
The living anionic polymerization processes of polyisoprene, polystyrene, and polystyrene-block-polyisoprene were studied by in-situ small-angle neutron scattering (SANS) in combination with gel permeation chromatography and uv-visible spectroscopy. The polymerization reactions were carried out in benzene-d6 with sec-butyllithium as the initiator. The SANS intensity largely decreased upon termination of the living ends, indicating the presence of ionic aggregates during polymerization. The time-courses of the aggregation number f in the aggregates during the polymerizations were quantitatively estimated by analyzing the time-resolved SANS data on the basis of the model of star-polymer. In isoprene systems, the aggregation number decreased from ca. 10 to 4 with increasing molecular weight.
Nishiuchi, Mamiko; Sakaki, Hironao; Sagisaka, Akito; Maeda, Shota; Pirozhkov, A. S.; Pikuz, T.; Faenov, A. Ya.*; Ogura, Koichi; Fukuda, Yuji; Matsukawa, Kenya*; et al.
no journal, ,
no abstracts in English
Maeda, Shota; Nishiuchi, Mamiko; Sakaki, Hironao; Sagisaka, Akito; Pirozhkov, A. S.; Pikuz, T.; Faenov, A. Ya.*; Ogura, Koichi; Fukuda, Yuji; Matsukawa, Kenya*; et al.
no journal, ,
In JAEA, the high energy ions generated by the interaction between Ultra-intense Ultra-Short pulse laser and thin-foil target is being studied. Irradiating condition must be optimized to generate higher energy ions while suppress the becoming gigantic of laser. It is necessary to know the physical phenomenon in plasma to determine the parameter to optimize from the information on the electron and neutron, X-rays, which are generated simultaneously with ion. In this study, in order to measure electron temperature accurately, an electron spectrometer was developed which have broad range (1-200 MeV). The detector is comprised of permanent magnets and a fluorescent plate, CCD camera. In the presentation, the result of the calibration experiment carried out using 4, 9, 12, 15 MeV quasi-monoenergetic electron beam in HIBMC will be reported. Moreover, response analysis method was inspected using PHITS which is particle transporting Monte Carlo simulation code, and will also report the result.
Nakamura, Mitsutaka; Kawakita, Yukinobu; Kambara, Wataru; Aoyama, Kazuhiro; Yamauchi, Yasuhiro; Kajimoto, Ryoichi; Ikeuchi, Kazuhiko*; Iida, Kazuki*; Inamura, Yasuhiro; Nakajima, Kenji; et al.
no journal, ,
In recent years, the need for neutron inelastic scattering experiments in special environments under the strong magnetic field and the high temperature is increasing. On the other hand, there is a problem that the unnecessary scattering originating from the sample environment devices affects the detection of weak inelastic signals. To solve this problem, we have been developing the radial collimator for chopper spectrometer at J-PARC. In this talk, we plan to introduce the performance evaluation results of our radial collimator.
Kajimoto, Ryoichi; Nakamura, Mitsutaka; Inamura, Yasuhiro; Ikeuchi, Kazuhiko*; Iida, Kazuki*; Ishikado, Motoyuki*; Suzuki, Junichi*; Nakajima, Kenji; Kawamura, Seiko; Nakatani, Takeshi; et al.
no journal, ,
no abstracts in English
Nakamura, Mitsutaka; Kawakita, Yukinobu; Kambara, Wataru; Yamauchi, Yasuhiro; Aoyama, Kazuhiro; Kajimoto, Ryoichi; Ikeuchi, Kazuhiko*; Iida, Kazuki*; Inamura, Yasuhiro; Nakajima, Kenji; et al.
no journal, ,
Recently, there is a growing need for neutron inelastic scattering experiments under special sample environments such as strong magnetic field and high temperatures. However the unwanted scattering originating from the sample environment equipment adversely affect the detection of weak inelastic signal. In order to overcome these difficulties, we have developed the radial collimators for chopper spectrometers at J-PARC. In this report we will show the results of performance evaluation tests for radial collimators.
Kajimoto, Ryoichi; Nakamura, Mitsutaka; Inamura, Yasuhiro; Kamazawa, Kazuya*; Ikeuchi, Kazuhiko*; Iida, Kazuki*; Ishikado, Motoyuki*; Suzuki, Junichi*; Nakajima, Kenji; Kawamura, Seiko; et al.
no journal, ,
no abstracts in English
Nakajima, Kenji; Kawamura, Seiko; Kikuchi, Tatsuya; Kawakita, Yukinobu; Inamura, Yasuhiro; Kajimoto, Ryoichi; Nakamura, Mitsutaka; Tanaka, Hiromichi; Iwahashi, Takaaki; Kambara, Wataru; et al.
no journal, ,
AMATERAS is a cold-neutron multi disk-chopper spectrometer at J-PARC. AMATERAS is designed to realize high intensity and fine and flexible energy resolution measurements in quasielastic and inelastic neutron scattering experiments from cold to thermal neutron energy region. AMATERAS had the first neutron beam in May 2009. After then, experiments of more than 70 proposals (including 17 in house projects proposals) have been carried out and results were distributed as 15 scientific papers and more than 100 presentations at domestic and international scientific meetings by users.
Nakajima, Kenji; Kawamura, Seiko; Kikuchi, Tatsuya; Kawakita, Yukinobu; Inamura, Yasuhiro; Kajimoto, Ryoichi; Nakamura, Mitsutaka; Soyama, Kazuhiko; Harada, Masahide; Oikawa, Kenichi; et al.
no journal, ,
