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Journal Articles

A Cubic CeBr$$_{3}$$ gamma-ray spectrometer suitable for the decommissioning of the Fukushima Daiichi Nuclear Power Station

Kaburagi, Masaaki; Shimazoe, Kenji*; Otaka, Yutaka*; Uenomachi, Mizuki*; Kamada, Kei*; Kim, K. J.*; Yoshino, Masao*; Shoji, Yasuhiro*; Yoshikawa, Akira*; Takahashi, Hiroyuki*; et al.

Nuclear Instruments and Methods in Physics Research A, 971, p.164118_1 - 164118_8, 2020/08

 Times Cited Count:0 Percentile:100(Instruments & Instrumentation)

Journal Articles

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

 Times Cited Count:0 Percentile:100

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.

Journal Articles

Cryogenic sample environments shared at the MLF, J-PARC

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 $$^4$$He cryostat, a bottom-loading $$^3$$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 $$^3$$He cryostat originally involves an operation software for automatic initial cooling down to the base temperature and automatic re-charge of $$^3$$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.

Journal Articles

Development of compact high field pulsed magnet system for new sample environment equipment at MLF in J-PARC

Watanabe, Masao; Nojiri, Hiroyuki*; Ito, Shinichi*; Kawamura, Seiko; Kihara, Takumi*; Masuda, Takatsugu*; Sahara, Takuro*; Soda, Minoru*; Takahashi, Ryuta

JPS Conference Proceedings (Internet), 25, p.011024_1 - 011024_5, 2019/03

Recently, neutron scattering experiments have been rapidly progressed under high magnetic field. In the J-PARC, proto-type compact pulse magnet system with the power supply, the coil and the sample stick has been developed. Basic specifications of the power supply are as follows; maximum charged voltage with capacitor is 2 kV, maximum current is 8 kA, repetition rate is a pulse per several minutes and pulse duration is several msec. Maximum magnetic field in the coil is more than 30 Tesla. The sample stick is designed for Orange-Cryostat. In this presentation, We report the details of the pulsed magnet system and the performance of it on neutron scattering experiments at MLF beam line (HRC).

Journal Articles

Study on use of superconducting magnet and first inelastic neutron scattering experiment under magnetic field at 4SEASONS spectrometer

Kajimoto, Ryoichi; Ishikado, Motoyuki*; Kira, Hiroshi*; Kaneko, Koji; Nakamura, Mitsutaka; Kamazawa, Kazuya*; Inamura, Yasuhiro; Ikeuchi, Kazuhiko*; Iida, Kazuki*; Murai, Naoki; et al.

Physica B; Condensed Matter, 556, p.26 - 30, 2019/03

 Times Cited Count:2 Percentile:57.6(Physics, Condensed Matter)

Journal Articles

Depth profile and inventory of $$^{36}$$Cl in soil near the Fukushima Dai-ichi Nuclear Power Plant

Ota, Yuki*; Sueki, Keisuke*; Sasa, Kimikazu*; Takahashi, Tsutomu*; Matsunaka, Tetsuya*; Matsumura, Masumi*; Tosaki, Yuki*; Honda, Maki*; Hosoya, Seiji*; Takano, Kenta*; et al.

JAEA-Conf 2018-002, p.99 - 102, 2019/02

no abstracts in English

Journal Articles

Anomaly of structural relaxation in complex liquid metal of bismuth; Dynamic correlation function of coherent quasi-elastic neutron scattering

Kawakita, Yukinobu; Kikuchi, Tatsuya*; Inamura, Yasuhiro; Tahara, Shuta*; Maruyama, Kenji*; Hanashima, Takayasu*; Nakamura, Mitsutaka; Kiyanagi, Ryoji; Yamauchi, Yasuhiro*; Chiba, Kaori*; et al.

Physica B; Condensed Matter, 551, p.291 - 296, 2018/12

 Times Cited Count:6 Percentile:43.39(Physics, Condensed Matter)

There are elemental liquid metals with complex structures far from the hard sphere (HS) packing model. Liquid Bi has an asymmetric first peak in the structure factors S(Q). The pair distribution function g(r) exhibits strange distance ratio of 1:2 between the first and the second peaks. Since a HS model with two kinds of radius produces asymmetry of the main peak in S(Q), existence of short-lived covalent bonds was discussed. Contrarily, modulation of the atomic distribution by the Friedel oscillations of shielding electrons around metallic ions was discussed. To examine its bonding nature from viewpoints of dynamic correlation functions, we have measured neutron quasielastic scattering of liquid Bi by using cold disk chopper spectrometer installed at MLF of J-PARC. The van Hove function revealed that the shoulder structure located at a longer side of the first peak in g(r) exhibits a longer relaxation time than the main structures such as the first and second peaks.

Journal Articles

Status report of the chopper spectrometer 4SEASONS

Kajimoto, Ryoichi; Nakamura, Mitsutaka; Inamura, Yasuhiro; Kamazawa, Kazuya*; Ikeuchi, Kazuhiko*; Iida, Kazuki*; Ishikado, Motoyuki*; Murai, Naoki; Kira, Hiroshi*; Nakatani, Takeshi; et al.

Journal of Physics; Conference Series, 1021(1), p.012030_1 - 012030_6, 2018/06

 Times Cited Count:2 Percentile:9.96

Journal Articles

Sample environment at the J-PARC MLF

Kawamura, Seiko; Oku, Takayuki; Watanabe, Masao; Takahashi, Ryuta; Munakata, Koji*; Takata, Shinichi; Sakaguchi, Yoshifumi*; Ishikado, Motoyuki*; Ouchi, Keiichi*; Hattori, Takanori; et al.

Journal of Neutron Research, 19(1-2), p.15 - 22, 2017/11

Sample environment (SE) team at the Materials and Life Science Experimental Facility (MLF) in J-PARC has worked on development and operation of SE equipment and devices. All the members belong to one sub-team at least, such as Cryogenic and magnet, High temperature, High pressure, Soft matter and special environment including Pulse magnet, Hydrogen environment, Light irradiation and $$^3$$He spin filter. Cryostats, a magnet, furnaces, a VX-6-type Paris-Edinburgh press and a prototype of a Spin-Exchange Optical Pumping (SEOP) based $$^3$$He spin filter for polarized neutron beam experiments are in operation. Furthermore, a prototype of compact power supply for a pulsed magnet system is currently developed. In the J-PARC Research Building, several pieces of equipment for softmatter research such as a rheometer and a gas and vapor adsorption measurement instrument have been prepared.

JAEA Reports

Radioactivity analysis of metal samples taken from pipes of the Fugen, 5

Haraga, Tomoko; Tobita, Minoru*; Takahashi, Shigemi*; Seki, Kotaro*; Izumo, Sari; Shimomura, Yusuke; Ishimori, Kenichiro; Kameo, Yutaka

JAEA-Data/Code 2016-017, 53 Pages, 2017/02

JAEA-Data-Code-2016-017.pdf:3.17MB

Fugen Nuclear Power Station was shut down and now is under decommissioning. Many radioactivity concentration data of dismantled materials have to be accumulated to calculate the scaling factors of radioactive wastes and to verify that the cleared dismantled materials conform to the clearance levels. A simple and rapid radioactivity determination method for radioactive waste samples was developed by Department of Decommissioning and Waste Management. For its demonstration, the simple and rapid radioactivity determination method was applied to metal samples, which were taken from dismantled pipes in contact with heavy water or carbon dioxide gas of Fugen. This report summarizes the radioactivity data obtained from the analysis of those samples.

JAEA Reports

Current status of a decommissioning project in the Enrichment Engineering Facility; Results in the second-half of the fiscal year of 2014

Matsumoto, Takashi; Takahashi, Nobuo; Hayashibara, Kenichi; Ishimori, Yuu; Mita, Yutaka; Kakiya, Hideyoshi

JAEA-Technology 2016-020, 80 Pages, 2016/11

JAEA-Technology-2016-020.pdf:17.8MB

The Enrichment Engineering Facility of the Ningyo-toge Environmental Engineering Center was constructed in order to establish the technological basis of plant engineering for uranium enrichment in Japan. Uranium enrichment tests, using natural and reprocessed uranium, were carried out from 1979 to 1989 with two types of centrifuges in the facility. According to the decommissioning plan of the facility, UF$$_{6}$$ handling equipment and supplemental equipment in these plants are intended to be dismantled by 2019 in order to make vacant spaces for future projects use, for example, inventory investigation, precipitation treatment, etc. This report shows the current state of the decommissioning project in the second-half of the fiscal year of 2014.

JAEA Reports

Radioactivity analysis of metal samples taken from pipes of the Fugen, 4

Haraga, Tomoko; Tobita, Minoru*; Takahashi, Shigemi*; Ishimori, Kenichiro; Kameo, Yutaka

JAEA-Data/Code 2015-025, 52 Pages, 2016/03

JAEA-Data-Code-2015-025.pdf:1.92MB

Fugen Nuclear Power Station was shut down and now is under decommissioning. Many radioactivity concentration data of dismantled materials have to be accumulated to calculate the scaling factors of radioactive wastes and verify that the cleared dismantled materials conform to the clearance levels. A simple and rapid radioactivity determination method for radioactive waste samples was developed in Department of Decommissioning and Waste Management. For the demonstration, the simple and rapid radioactivity determination method was applied to metal samples, which were taken from dismantled pipes of Fugen. This report summarizes the radioactivity data obtained from the analysis of those samples.

Journal Articles

Method of dynamic image measurement for analyzing cricket behavior

Takahashi, Satoru*; Okuda, Yasutake*; Kawabata, Kuniaki; Aonuma, Hitoshi*; Sato, Yutaka*; Iwata, Kenji*

Journal of Signal Processing, 20(2), p.65 - 74, 2016/03

Journal Articles

Progress of divertor simulation research toward the realization of detached plasma using a large tandem mirror device

Nakashima, Yosuke*; Takeda, Hisahito*; Ichimura, Kazuya*; Hosoi, Katsuhiro*; Oki, Kensuke*; Sakamoto, Mizuki*; Hirata, Mafumi*; Ichimura, Makoto*; Ikezoe, Ryuya*; Imai, Tsuyoshi*; et al.

Journal of Nuclear Materials, 463, p.537 - 540, 2015/08

 Times Cited Count:17 Percentile:8.28(Materials Science, Multidisciplinary)

Journal Articles

Precise determination of $$^{12}_{Lambda}$$C level structure by $$gamma$$-ray spectroscopy

Hosomi, Kenji; Ma, Y.*; Ajimura, Shuhei*; Aoki, Kanae*; Dairaku, Seishi*; Fu, Y.*; Fujioka, Hiroyuki*; Futatsukawa, Kenta*; Imoto, Wataru*; Kakiguchi, Yutaka*; et al.

Progress of Theoretical and Experimental Physics (Internet), 2015(8), p.081D01_1 - 081D01_8, 2015/08

 Times Cited Count:12 Percentile:28.16(Physics, Multidisciplinary)

Level structure of the $$^{12}_{Lambda}$$C hypernucleus was precisely determined by means of $$gamma$$-ray spectroscopy. We identified four $$gamma$$-ray transitions via the $$^{12}$$C$$(pi^{+},K^{+}gamma)$$ reaction using a germanium detector array, Hyperball2. The spacing of the ground-state doublet $$(2^{-}, 1^{-}_{1})$$ was measured to be $$161.5pm0.3$$(stat)$$pm0.3$$ (syst)keV from the direct $$M1$$ transition. Excitation energies of the $$1^{-}_{2}$$ and $$1^{-}_{3}$$ states were measured to be $$2832pm3pm4$$, keV and $$6050pm8pm7$$, keV, respectively. The obtained level energies provide definitive references for the reaction spectroscopy of $$Lambda$$ hypernuclei.

Journal Articles

Inter-atomic force constants of BaF$$_{2}$$ by diffuse neutron scattering measurement

Sakuma, Takashi*; Makhsun*; Sakai, Ryutaro*; Xianglian*; Takahashi, Haruyuki*; Basar, K.*; Igawa, Naoki; Danilkin, S. A.*

AIP Conference Proceedings 1656, p.020002_1 - 020002_4, 2015/04

 Times Cited Count:1 Percentile:100

Diffuse neutron scattering measurement on BaF$$_{2}$$ crystals was performed at 10 K and 295 K. Oscillatory form in the diffuse scattering intensity of BaF$$_{2}$$ was observed at 295 K. The correlation effects among thermal displacements of F-F atoms were obtained from the analysis of oscillatory diffuse scattering intensity. From the values of correlation effects and Debye-Waller temperature parameters, force constants among the first and second nearest neighboring atoms of BaF$$_{2}$$, were determined to be 4.40 and 2.30 eV/$AA$^{2}$$ at 295 K, respectively

Journal Articles

Determination of $$^{129}$$I in the Accumulated radioactive water and processing water of the Fukushima Daiichi Nuclear Power Plant

Shimada, Asako; Sakatani, Keiichi; Kameo, Yutaka; Takahashi, Kuniaki

Journal of Radioanalytical and Nuclear Chemistry, 303(2), p.1137 - 1140, 2015/02

 Times Cited Count:3 Percentile:62.98(Chemistry, Analytical)

Accumulated radioactive water and processing water were sampled from back and forth of the Accumulated radioactive water processing facility (ARWPF) at Fukushima Daiichi Nuclear Power Plant (FDNPP) to estimate the radioactivity of the secondary waste such as zeolite and sludge adsorbed radioactive material. Separation method of I$$^{-}$$ from the radioactive materials using solid phase extractant, Anion-SR, was developed, and the concentration of $$^{129}$$I in the accumulated water and processing water was determined by Inductively Coupled Plasma Mass Spectrometry including dynamic reaction cell (DRC-ICP-MS).

Journal Articles

Development of a rapid analytical method for $$^{129}$$I in the contaminated water and tree samples at the Fukushima Daiichi Nuclear Power Station

Shimada, Asako; Ozawa, Mayumi; Kameo, Yutaka; Yasumatsu, Takuyo*; Nebashi, Koji*; Niiyama, Takuya; Seki, Shuhei; Kajio, Masatoshi; Takahashi, Kuniaki

Nuclear Back-end and Transmutation Technology for Waste Disposal, p.311 - 317, 2015/00

no abstracts in English

Journal Articles

Numerical analysis of air-hydrogen mixture flow in rectangular indoor space with ventilators

Sugiyama, Hitoshi*; Takahashi, Keita*; Kato, Naoto*; Terada, Atsuhiko; Kamiji, Yu; Hino, Ryutaro

Jidosha Gijutsukai Gakujutsu Koenkai Zensatsushu, (109-14), p.5 - 10, 2014/10

Numerical analysis has been performed for vertical buoyant flow of air-hydrogen mixture in rectangular indoor space with ventilators. The unsteady and laminar flow has been calculated by using the coupled conservation equations of hydrogen and momentum. Calculated results are compared with the experiment data of hydrogen concentration and velocity profile in order to confirm the validity of the presented numerical method and clarify the mechanism of hydrogen dispersion. Although agreement is certainly not perfect in all detail, the main features are reasonably reproduced. Adding to this, calculated results suggest that hydrogen concentration depends on Froude number.

212 (Records 1-20 displayed on this page)