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Journal Articles

Design and actual performance of J-PARC 3 GeV rapid cycling synchrotron for high-intensity operation

Yamamoto, Kazami; Kinsho, Michikazu; Hayashi, Naoki; Saha, P. K.; Tamura, Fumihiko; Yamamoto, Masanobu; Tani, Norio; Takayanagi, Tomohiro; Kamiya, Junichiro; Shobuda, Yoshihiro; et al.

Journal of Nuclear Science and Technology, 59(9), p.1174 - 1205, 2022/09

 Times Cited Count:1 Percentile:62.84(Nuclear Science & Technology)

In the Japan Proton Accelerator Research Complex, the purpose of the 3 GeV rapid cycling synchrotron (RCS) is to accelerate a 1 MW, high-intensity proton beam. To achieve beam operation at a repetition rate of 25 Hz at high intensities, the RCS was elaborately designed. After starting the RCS operation, we carefully verified the validity of its design and made certain improvements to establish a reliable operation at higher power as possible. Consequently, we demonstrated beam operation at a high power, namely, 1 MW. We then summarized the design, actual performance, and improvements of the RCS to achieve a 1 MW beam.

Journal Articles

Rotation of complex ions with ninefold hydrogen coordination studied by quasielastic neutron scattering and first-principles molecular dynamics calculations

Omasa, Yoshinori*; Takagi, Shigeyuki*; Toshima, Kento*; Yokoyama, Kaito*; Endo, Wataru*; Orimo, Shinichi*; Saito, Hiroyuki*; Yamada, Takeshi*; Kawakita, Yukinobu; Ikeda, Kazutaka*; et al.

Physical Review Research (Internet), 4(3), p.033215_1 - 033215_9, 2022/09

Journal Articles

Sorption of Cs$$^{+}$$ and Eu$$^{3+}$$ ions onto sedimentary rock in the presence of gamma-irradiated humic acid

Zhao, Q.*; Saito, Takeshi*; Miyakawa, Kazuya; Sasamoto, Hiroshi; Kobayashi, Taishi*; Sasaki, Takayuki*

Journal of Hazardous Materials, 428, p.128211_1 - 128211_10, 2022/04

 Times Cited Count:1 Percentile:45.14(Engineering, Environmental)

The influence of humic acid and its radiological degradation on the sorption of Cs$$^{+}$$ and Eu$$^{3+}$$ by sedimentary rock was investigated to understand the sorption process of metal ions and humic substances. Aldrich humic acid (HA) solution was irradiated with different doses of gamma irradiation using a Co-60 gamma-ray source prior to the contact between the metal ions and the solid sorbent. The HA molecule decomposed to smaller molecules with a lower complexation affinity. Batch sorption experiments were performed to evaluate the effect of gamma-irradiated HA on the sorption of Cs$$^{+}$$ and Eu$$^{3+}$$ ions. The addition of non-irradiated HA weakened the sorption of Eu because of the lower sorption of the neutral or negatively charged Eu-HA complexes compared with free Eu ions. The sorption of monovalent Cs ions was barely affected by the presence of HA and its gamma irradiation. The concentration ratio of HA complexed species and non-complexed species in the solid and liquid phases was evaluated by sequential filtration and chemical equilibrium calculations. The ratios supported the minimal contribution of HA to Cs sorption. However, the concentration ratio for Eu$$^{3+}$$ in the liquid phase was high, indicating that the complexing ability of HA to Eu$$^{3+}$$ was higher than that of HA to Cs$$^{+}$$ ions. Therefore, the sorption of free Eu$$^{3+}$$ would predominate with the gamma irradiation dose applied to the HA solution under a radiation field near the HLW package.

Journal Articles

Dynamics of water in a catalyst layer of a fuel cell by quasielastic neutron scattering

Ito, Kanae; Yamada, Takeshi*; Shinohara, Akihiro*; Takata, Shinichi; Kawakita, Yukinobu

Journal of Physical Chemistry C, 125(39), p.21645 - 21652, 2021/10

 Times Cited Count:2 Percentile:25.35(Chemistry, Physical)

Journal Articles

Evaluation of edge domains in giant magnetoresistive junctions

Frost, W.*; Seki, Takeshi*; Kubota, Takahide*; Ramos, R.*; Saito, Eiji; Takanashi, Koki*; Hirohata, Atsufumi*

Applied Physics Letters, 118(17), p.172405_1 - 172405_5, 2021/04

 Times Cited Count:1 Percentile:0(Physics, Applied)

Journal Articles

Nonmagnetic-magnetic transition and magnetically ordered structure in SmS

Yoshida, Shogo*; Koyama, Takehide*; Yamada, Haruhiko*; Nakai, Yusuke*; Ueda, Koichi*; Mito, Takeshi*; Kitagawa, Kentaro*; Haga, Yoshinori

Physical Review B, 103(15), p.155153_1 - 155153_5, 2021/04

 Times Cited Count:0 Percentile:0(Materials Science, Multidisciplinary)

Journal Articles

Reliability of J-PARC accelerator system over the past decade

Yamamoto, Kazami; Hasegawa, Kazuo; Kinsho, Michikazu; Oguri, Hidetomo; Hayashi, Naoki; Yamazaki, Yoshio; Naito, Fujio*; Yoshii, Masahito*; Toyama, Takeshi*

JPS Conference Proceedings (Internet), 33, p.011016_1 - 011016_7, 2021/03

The Japan Proton Accelerator Research Complex (J-PARC) is a multipurpose facility for scientific experiments. The accelerator complex consists of a 400-MeV Linac, a 3-GeV Rapid-Cycling Synchrotron (RCS) and a 30-GeV Main Ring synchrotron (MR). The RCS delivers a proton beam to the neutron target and MR, and the MR delivers the beams to the neutrino target and the Hadron Experimental Facility. The first operation of the neutron experiments began in December 2008. Following this, the user operation has been continued with some accidental suspensions. These suspensions include the recovery work due to the Great East Japan Earthquake in March 2011 and the radiation leak incident at the Hadron Experimental Facility. In this report, we summarize the major causes of suspension, and the statistics of the reliability of J-PARC accelerator system is analyzed. Owing to our efforts to achieve higher reliability, the Mean Time Between Failure (MTBF) has been improved.

Journal Articles

Simultaneous determination of zircon U-Pb age and titanium concentration using LA-ICP-MS for crystallization age and temperature

Yuguchi, Takashi*; Ishibashi, Kozue*; Sakata, Shuhei*; Yokoyama, Tatsunori; Ito, Daichi*; Ogita, Yasuhiro; Yagi, Koshi*; Ono, Takeshi*

Lithos, 372-373, p.105682_1 - 105682_9, 2020/11

 Times Cited Count:1 Percentile:10.2(Geochemistry & Geophysics)

Simultaneous determination of zircon U-Pb age and titanium concentration for a single analysis spot gives both the crystallization age and temperature. The crystallization age and temperature pairs in granitic zircons map the time-temperature ($$t-T$$) path of granitic magma before its solidification. In laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analysis, it is challenging to quantitatively analyse a low level of titanium concentration. This study employed two approaches using a Quadrupole mass spectrometer equipped with a collision/reaction cell (CRC). The methods were applied to zircon samples of the Kurobegawa granite (KRG), the Okueyama granite (OKG), the Toki granite (TKG), and the Tono plutonic complex (TPC) and provided U-Pb ages and titanium concentrations consistent with previous studies. The crystallization ages and temperatures collected from individual analysis spots of zircon samples in the KRG, OKG, TKG, and TPC are plotted in the $$t-T$$ diagrams and enable us to characterize the rapid cooling paths at thermal conditions of zircon crystallization at the sampling sites.

Journal Articles

Relation between biomolecular dissociation and energy of secondary electrons generated in liquid water by fast heavy ions

Tsuchida, Hidetsugu*; Kai, Takeshi; Kitajima, Kensei*; Matsuya, Yusuke; Majima, Takuya*; Saito, Manabu*

European Physical Journal D, 74(10), p.212_1 - 212_7, 2020/10

 Times Cited Count:2 Percentile:22.88(Optics)

Fundamental study of interaction between biomolecules and heavy ions in water is very important to predict an initial stage of radiation biological effects. A heavy ion irradiation experiment into droplet target assumed as a biological system in a vacuum was performed to measure production yields of cations and anions for glycine, which was ejected from the droplet target to the vacuum. However, the production mechanisms have been unknown. The PHITS code adapting ion track structure mode was used to analyze the production mechanisms from the dose evaluation at the surface between the vacuum and the water. It is found that induction yields of ionization and excitation, and dissociative electron attachment involved in the secondary electrons were correlated with the production yields of cations and anions of the glycine. The results provide us newly scientific insights to predict an initial stage of radiation biological effects.

Journal Articles

Effects of diluents on the separation of minor actinides from lanthanides with tetradodecyl-1,10-phenanthroline-2,9-diamide from nitric acid medium

Tsutsui, Nao; Ban, Yasutoshi; Suzuki, Hideya*; Nakase, Masahiko*; Ito, Sayumi*; Inaba, Yusuke*; Matsumura, Tatsuro; Takeshita, Kenji*

Analytical Sciences, 36(2), p.241 - 246, 2020/02

 Times Cited Count:13 Percentile:69.52(Chemistry, Analytical)

To investigate the effective separation of actinides (Ans) from lanthanides (Lns), single-stage batch extraction experiments were performed with a novel extractant, tetradodecyl-1,10-phenanthroline-2,9-diamide (TDdPTDA) with various diluents such as 3-nitrobenzotrifluoride (F-3), nitrobenzene, and ${it n}$-dodecane for Am, Cm, and Lns. The extraction kinetics with TDdPTDA was rapid enough to perform the actual extraction flow sheet. The slopes of the distribution ratio versus TDdPTDA concentration and the distribution ratio versus nitric acid concentration were similar for F-3 and nitrobenzene systems but different from ${it n}$-dodecane system. These differences were attributed to the characteristics of the diluents. This study reveals high distribution ratios of Am (${it D}$ $$_{Am}$$) and Cm (${it D}$ $$_{Cm}$$) for TDdPTDA, with the high separation factors (${it SF}$s) of Am from Lns enough for their separation.

Journal Articles

Enhancement of element production by incomplete fusion reaction with weakly bound deuteron

Wang, H.*; Otsu, Hideaki*; Chiga, Nobuyuki*; Kawase, Shoichiro*; Takeuchi, Satoshi*; Sumikama, Toshiyuki*; Koyama, Shumpei*; Sakurai, Hiroyoshi*; Watanabe, Yukinobu*; Nakayama, Shinsuke; et al.

Communications Physics (Internet), 2(1), p.78_1 - 78_6, 2019/07

 Times Cited Count:7 Percentile:57.83(Physics, Multidisciplinary)

Searching for effective pathways for the production of proton- and neutron-rich isotopes through an optimal combination of reaction mechanism and energy is one of the main driving forces behind experimental and theoretical nuclear reaction studies as well as for practical applications in nuclear transmutation of radioactive waste. We report on a study on incomplete fusion induced by deuteron, which contains one proton and one neutron with a weak binding energy and is easily broken up. This reaction study was achieved by measuring directly the cross sections for both proton and deuteron for $$^{107}$$Pd at 50 MeV/u via inverse kinematics technique. The results provide direct experimental evidence for the onset of a cross-section enhancement at high energy, indicating the potential of incomplete fusion induced by loosely-bound nuclei for creating proton-rich isotopes and nuclear transmutation of radioactive waste.

Journal Articles

Status of J-PARC accelerators

Hasegawa, Kazuo; Kinsho, Michikazu; Oguri, Hidetomo; Yamamoto, Kazami; Hayashi, Naoki; Yamazaki, Yoshio; Naito, Fujio*; Yoshii, Masahito*; Toyama, Takeshi*; Yamamoto, Noboru*; et al.

Proceedings of 16th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1235 - 1239, 2019/07

After the summer shutdown in 2018, the J-PARC restarted user operation in late October. While beam power to the Materials and Life Science Experimental Facility (MLF) was 500 kW as before the summer shutdown, linac beam current was increased from 40 to 50 mA. Operation of the Main Ring (MR) was suspended due to the modification and/or maintenance of the Superkamiokande (neutrino detector) and Hadron experimental facility. The user operation was resumed in the middle of February for the Hadron experimental facility at 51 kW. But on March 18, one of the bending magnets in the beam transport line to the MR had a failure. It was temporary recovered and restored beam operation on April 5, but the failure occurred again on April 24 and the beam operation of the MR was suspended. In the fiscal year of 2018, the availabilities for the MLF, neutrino and hadron facilities are 94%, 86%, and 74%, respectively.

Journal Articles

Mapping measurement for beam energy position monitor system for RIKEN superconducting acceleration cavity

Watanabe, Tamaki*; Toyama, Takeshi*; Hanamura, Kotoku*; Imao, Hiroshi*; Kamigaito, Osamu*; Kamoshida, Atsushi*; Kawachi, Toshihiko*; Koyama, Ryo*; Sakamoto, Naruhiko*; Fukunishi, Nobuhisa*; et al.

Proceedings of 16th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1105 - 1108, 2019/07

Upgrades for the RIKEN heavy-ion linac (RILAC) involving a new superconducting linac (SRILAC) are currently underway at the RIKEN radioactive isotope beam factory (RIBF). It is crucially important to develop nondestructive beam measurement diagnostics. We have developed a beam energy position monitor (BEPM) system which can measure not only the beam position but also the beam energy simultaneously by measuring the time of flight of the beam. We fabricated 11 BEPMs and completed the position calibration to obtain the sensitivity and offset for each BEPMs. The position accuracy has been achieved to be less than $$pm$$ 0.1 mm by using the mapping measurement.

Journal Articles

Development of beam energy position monitor system for RIKEN superconducting acceleration cavity

Watanabe, Tamaki*; Imao, Hiroshi*; Kamigaito, Osamu*; Sakamoto, Naruhiko*; Fukunishi, Nobuhisa*; Fujimaki, Masaki*; Yamada, Kazunari*; Watanabe, Yutaka*; Koyama, Ryo*; Toyama, Takeshi*; et al.

Proceedings of 15th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.49 - 54, 2018/08

no abstracts in English

Journal Articles

Stroboscopic time-of-flight neutron diffraction during cyclic testing using the event data recording system at J-PARC

Kawasaki, Takuro; Inamura, Yasuhiro; Ito, Takayoshi*; Nakatani, Takeshi; Harjo, S.; Gong, W.*; Aizawa, Kazuya

Journal of Applied Crystallography, 51(3), p.630 - 634, 2018/06

 Times Cited Count:3 Percentile:32.88(Chemistry, Multidisciplinary)

JAEA Reports

Comprehensive evaluation system for environmental remediation of Fukushima; Toward integration of three components as a whole system

Saito, Hiroshi; Nozawa, Takashi; Takemiya, Hiroshi; Seki, Akiyuki; Matsubara, Takeshi; Saito, Kimiaki; Kitamura, Akihiro

JAEA-Review 2017-040, 34 Pages, 2018/03

JAEA-Review-2017-040.pdf:9.52MB

The accidents at Fukushima Daiichi Nuclear Power Station on March 11th 2011, released significant amount of radionuclide to the environment. It has migrated to the human habitation and raised concerns of possible effect on human health, and for that a lot of researches have been performed. JAEA created and opened "Database for Radioactive Substance Monitoring Data" for usage of obtained data. For accurate modelling and future forecast using numerical code and the data, "Supporting Environment for Processing Simulation Codes" has been operated. In addition, research results have been opened as Q&A style "Knowledge Base for Environmental Remediation" in JAEA's website. The "Comprehensive Evaluation System" composed of these components, should act more interrelated and integrated as one system. Besides, information dissemination is not enough to the outside. The report summarizes the current status, remaining issues and expected improvement of each component and the system.

Journal Articles

Turbulent transport reduction induced by transition on radial electric field shear and curvature through amplitude and cross-phase in torus plasma

Kobayashi, Tatsuya*; Ito, Kimitaka*; Ido, Takeshi*; Kamiya, Kensaku*; Ito, Sanae*; Miura, Yukitoshi; Nagashima, Yoshihiko*; Fujisawa, Akihide*; Inagaki, Shigeru*; Ida, Katsumi*

Scientific Reports (Internet), 7(1), p.14971_1 - 14971_8, 2017/11

 Times Cited Count:21 Percentile:80.22(Multidisciplinary Sciences)

Journal Articles

Materials and Life Science Experimental Facility at the Japan Proton Accelerator Research Complex, 3; Neutron devices and computational and sample environments

Sakasai, Kaoru; Sato, Setsuo*; Seya, Tomohiro*; Nakamura, Tatsuya; To, Kentaro; Yamagishi, Hideshi*; Soyama, Kazuhiko; Yamazaki, Dai; Maruyama, Ryuji; Oku, Takayuki; et al.

Quantum Beam Science (Internet), 1(2), p.10_1 - 10_35, 2017/09

Neutron devices such as neutron detectors, optical devices including supermirror devices and $$^{3}$$He neutron spin filters, and choppers are successfully developed and installed at the Materials Life Science Facility (MLF) of the Japan Proton Accelerator Research Complex (J-PARC), Tokai, Japan. Four software components of MLF computational environment, instrument control, data acquisition, data analysis, and a database, have been developed and equipped at MLF. MLF also provides a wide variety of sample environment options including high and low temperatures, high magnetic fields, and high pressures. This paper describes the current status of neutron devices, computational and sample environments at MLF.

Journal Articles

Time-of-flight elastic and inelastic neutron scattering studies on the localized 4d electron layered perovskite La$$_5$$Mo$$_4$$O$$_{16}$$

Iida, Kazuki*; Kajimoto, Ryoichi; Mizuno, Yusuke*; Kamazawa, Kazuya*; Inamura, Yasuhiro; Hoshikawa, Akinori*; Yoshida, Yukihiko*; Matsukawa, Takeshi*; Ishigaki, Toru*; Kawamura, Yukihiko*; et al.

Journal of the Physical Society of Japan, 86(6), p.064803_1 - 064803_6, 2017/06

 Times Cited Count:1 Percentile:13.06(Physics, Multidisciplinary)

Journal Articles

Inelastic and quasi-elastic neutron scattering spectrometers in J-PARC

Seto, Hideki; Ito, Shinichi; Yokoo, Tetsuya*; Endo, Hitoshi*; Nakajima, Kenji; Shibata, Kaoru; Kajimoto, Ryoichi; Kawamura, Seiko; Nakamura, Mitsutaka; Kawakita, Yukinobu; et al.

Biochimica et Biophysica Acta; General Subjects, 1861(1), p.3651 - 3660, 2017/01

 Times Cited Count:28 Percentile:80.43(Biochemistry & Molecular Biology)

J-PARC, Japan Proton Accelerator Research Complex provides short pulse proton beam at a repetition rate 25 Hz and the maximum power is expected to be 1 MW. Materials and Life Science Experimental Facility (MLF) has 23 neutron beam ports and 21 instruments have already been operated or under construction / commissioning. There are 6 inelastic / quasi-elastic neutron scattering spectrometers and the complementary use of these spectrometers will open new insight for life science.

619 (Records 1-20 displayed on this page)