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Be and 
Al under direct muon-induced spallation in granite quartz and its implications for past high-energy cosmic ray fluxesSakurai, Hirohisa*; Kurebayashi, Yutaka*; Suzuki, Soichiro*; Horiuchi, Kazuho*; Takahashi, Yui*; Doshita, Norihiro*; Kikuchi, Satoshi*; Tokanai, Fuyuki*; Iwata, Naoyoshi*; Tajima, Yasushi*; et al.
Physical Review D, 109(10), p.102005_1 - 102005_18, 2024/05
Times Cited Count：0 Percentile：0.00(Astronomy & Astrophysics)Secular variations of galactic cosmic rays (GCRs) are inseparably associated with the galactic activities and should reflect the environments of the local galactic magnetic field, interstellar clouds, and nearby supernova remnants. The high-energy muons produced in the atmosphere by high-energy GCRs can penetrate deep underground and generate radioisotopes in the rock. As long lived radionuclides such as Be and Al have been accumulating in these rocks, concentrations of Be and Al can be used to estimate the long-term variations in high-energy muon yields, corresponding to those in the high-energy GCRs over a few million years. This study measured the production cross sections for muon induced Be and Al by irradiating positive muons with the momentum of 160 GeV/c on the synthetic silica plates and the granite core at the COMPASS experiment line in CERN SPS. In addition, it the contributions of the direct muon spallation reaction and the nuclear reactions by muon-induced particles on the production of long lived radionuclides in the rocks were clarified.
-wave resonance of 
+
Okudaira, Takuya*; Nakabe, Rintaro*; Auton, C. J.*; Endo, Shunsuke; Fujioka, Hiroyuki*; Gudkov, V.*; Ide, Ikuo*; Ino, Takashi*; Ishikado, Motoyuki*; Kambara, Wataru*; et al.
Physical Review C, 109(4), p.044606_1 - 044606_9, 2024/04
Times Cited Count：2 Percentile：78.45(Physics, Nuclear)
-odd/
-odd interactions on the 0.75 eV -wave resonance in 
+
forward transmission determined using a pulsed neutron beamNakabe, Rintaro*; Auton, C. J.*; Endo, Shunsuke; Fujioka, Hiroyuki*; Gudkov, V.*; Hirota, Katsuya*; Ide, Ikuo*; Ino, Takashi*; Ishikado, Motoyuki*; Kambara, Wataru*; et al.
Physical Review C, 109(4), p.L041602_1 - L041602_4, 2024/04
Times Cited Count：1 Percentile：23.17(Physics, Nuclear)Takahashi, Tone; Yamaguchi, Ikuto*; Hironaka, Kota*; Mochimaru, Takanori*; Koizumi, Mitsuo; Yamanishi, Hirokuni*; Wakabayashi, Genichiro*
Dai-44-Kai Nihon Kaku Busshitsu Kanri Gakkai Nenji Taikai Kaigi Rombunshu (Internet), 4 Pages, 2023/11
To enhance the counter capability against terrorism in major public events, the Japan Atomic Energy Agency (JAEA) has started developments of monitoring technique that covers wide-area and rapidly detects nuclear and radioactive materials. In this project, we are developing widely applicable radiation mapping device by combining with positioning sensors and a network device. Mapping tests inside and outside of the building by using the device to locate areas with high radiation count has been performed. Also, fast neutron detection technique using plastic scintillation detectors is being developed for detection of neutron sources including nuclear materials. Measurement with two rod shaped detector that placed into a cross showed better localizing capability compared with single detector. In this report, recent progresses of the project are given.
Koizumi, Mitsuo; Takahashi, Tone; Hironaka, Kota; Mochimaru, Takanori*; Yamaguchi, Ikuto*; Kimura, Yoshiki; Tanigaki, Minoru*; Masaki, Hiroko*; Harada, Hiroshi*; Goto, Jun*; et al.
Proceedings of INMM & ESARDA Joint Annual Meeting 2023 (Internet), 7 Pages, 2023/05
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：7 Percentile：74.40(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.
Yamane, Ikumi; Takahashi, Nobuo; Sawayama, Kengo; Nishiwaki, Hiroki; Matsumoto, Takashi; Ogawa, Jumpei; Nomura, Mitsuo; Arima, Tatsumi*
JAEA-Technology 2021-038, 18 Pages, 2022/02
JAEA-Technology-2021-038.pdf:1.61MB
We have dismantled uranium enrichment facilities in Ningyo-toge Environmental Engineering Center since their operation finished in 2001, and the total amount of metallic wastes is estimated to be about 130 thousand tons. Eighty percent of them can be disposed as nonradioactive waste (NR), but there are some steel parts possibly uranium-contaminated. We need removing painted surface of such steels and radiologically surveying to dispose them as NRs. Though painted surfaces have been conventionally removed through hand working with grinders, this manual work requires installation of green house, protective clothing, and full-face mask, in order to prevent dispersion and inhalation of airborne dusts. We desire further developments of surface cleaning techniques to reduce time, cost, workload, and secondary waste generation caused by excessive grinding. Therefore, in this study, we focused on the laser cleaning technology used for the separation and removal of paint films at construction sites. In order to improve the coating separation and removal technology for NR objects, we evaluated the coating separation and removal performance of NR steel surface by laser cleaning system, observed the coating scattering behavior by high-speed camera and investigated the coating recovery method, evaluated the laser separation and removal performance of steel surface powder, and thermodynamically evaluated the uranium compounds on steel surface. We additionally evaluated the feasibility of laser cleaning techniques in our works basing on these results, and discussed future work plans for further developments of laser cleaning techniques.
Tamura, Fumihiko; Takahashi, Hiroki; Kamikubota, Norihiko*; Ito, Yuichi*; Hayashi, Naoki
IEEE Transactions on Nuclear Science, 68(8), p.2043 - 2050, 2021/08
Times Cited Count：0 Percentile：0.00(Engineering, Electrical & Electronic)A precise and stable timing system is necessary for high intensity proton accelerators such as the J-PARC. The existing timing system, which was developed during the construction period of the-PARC, has been working without major issues since 2006. After a decade of operation, the optical modules, which are key components for signal transfer, were discontinued already. Thus, the next-generation timing system for the J-PARC is under development. The new system is designed to be compatible with the existing system in terms of the operating principle. The new system utilizes modern high speed signal communication for the transfer of the clock, trigger, and type code. We present the system configuration of the next-generation timing system and current status.
Sakakibara, Hiroshi; Aoki, Nobuhiro; Muto, Masahiro; Otabe, Jun; Takahashi, Kenji*; Fujita, Naoyuki*; Hiyama, Kazuhiko*; Suzuki, Hirokazu*; Kamogawa, Toshiyuki*; Yokosuka, Toru*; et al.
JAEA-Technology 2020-020, 73 Pages, 2021/03
JAEA-Technology-2020-020.pdf:8.26MB
The decommissioning is currently in progress at the prototype fast breeder reactor Monju. Fuel assemblies will be taken out of its core for the first step of the great task. Fuel assemblies stand on their own spike plugged into a socket on the core support plate and support with adjacent assemblies through their housing pads each other, resulting in steady core structure. For this reason, some substitutive assemblies are necessary for the purpose of discharging the fuel assemblies of the core. Monju side commissioned, therefore, Plutonium Fuel Development Center to manufacture the substitutive assemblies and the Center accepted it. This report gives descriptions of design, manufacture, and shipment in regard to the substitutive assemblies.
Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Takagi, Yasuhiko*; Nakamura, Tomoki*; Hiroi, Takahiro*; Matsuoka, Moe*; et al.
Nature Astronomy (Internet), 5(3), p.246 - 250, 2021/03
Times Cited Count：58 Percentile：96.23(Astronomy & Astrophysics)Here we report observations of Ryugu's subsurface material by the Near-Infrared Spectrometer (NIRS3) on the Hayabusa2 spacecraft. Reflectance spectra of excavated material exhibit a hydroxyl (OH) absorption feature that is slightly stronger and peak-shifted compared with that observed for the surface, indicating that space weathering and/or radiative heating have caused subtle spectral changes in the uppermost surface. However, the strength and shape of the OH feature still suggests that the subsurface material experienced heating above 300 
C, similar to the surface. In contrast, thermophysical modeling indicates that radiative heating does not increase the temperature above 200 C at the estimated excavation depth of 1 m, even if the semimajor axis is reduced to 0.344 au. This supports the hypothesis that primary thermal alteration occurred due to radiogenic and/or impact heating on Ryugu's parent body.
Miao, P.*; Tan, Z.*; Lee, S. H.*; Ishikawa, Yoshihisa*; Torii, Shuki*; Yonemura, Masao*; Koda, Akihiro*; Komatsu, Kazuki*; Machida, Shinichi*; Sano, Asami; et al.
Physical Review B, 103(9), p.094302_1 - 094302_18, 2021/03
Times Cited Count：4 Percentile：24.33(Materials Science, Multidisciplinary)The layered perovskite PrBaCo
O
demonstrates a strong negative thermal expansion (NTE) which holds potential for being fabricated into composites with zero thermal expansion. The NTE was found to be intimately associated with the spontaneous magnetic ordering, known as magneto-volume effect (MVE). Here we report with compelling evidences that the continuous-like MVE in PrBaCoO is intrinsically of discontinuous character, originating from an magnetoelectric transition from an antiferromagnetic insulating large-volume (AFILV) phase to a ferromagnetic less-insulating small-volume (FLISV) phase. Furthermore, the magnetoelectric effect (ME) shows high sensitivity to multiple external stimuli such as temperature, carrier doping, hydrostatic pressure, magnetic field etc. In contrast to the well-known ME such as colossal magnetoresistance and multi-ferroic effect which involve symmetry breaking of crystal structure, the ME in the cobaltite is purely isostructural. Our discovery provides a new path way to realizing the ME as well as the NTE, which may find applications in new techniques.
Tamura, Fumihiko; Yoshii, Masahito*; Kamikubota, Norihiko*; Takahashi, Hiroki
Proceedings of 17th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.68 - 72, 2020/09
MTCA (MicroTCA) is expected to be the next generation platform for advanced control in accelerators. MTCA has many advantages over the widely used VMEs, such as high speed, large data transfer capacity, and high maintainability with hot-swappable modules. After the application to the LLRF control system at KEK, MTCA has been used in many accelerators around the world, while it takes a long time for MTCA to spread to the accelerators in Japan. Recently, the number of large-scale adoptions such as the LLRF control system, for the J-PARC RCS has been increasing. In this article, we introduce a case study of MTCA adoption and discuss why MTCA has not been widely used in Japan. Also, the efforts for the future promotion of MTCA in Japan are reported.
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：2 Percentile：68.99(Physics, Particles & Fields)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.
Shintaku, Yuichi*; Shinozaki, Yuto*; Fujiwara, Takaki*; Takahashi, Akiyuki*; Kikuchi, Masanori
Nihon Kikai Gakkai Rombunshu (Internet), 85(876), p.19-00141_1 - 19-00141_15, 2019/08
The contribution of this paper is to develop two kinds of numerical simulation method for fatigue crack propagation with plastic-induced crack closure under different cyclic loading conditions. One of the developed methods is Direct Numerical Simulation (DNS) using S-version FEM that allow us to simulate by combining with global mesh only representing whole structure and local mesh including crack. After stress intensity factor is calculated by S-version FEM, crack opening level due to plastic-induced crack closure is determined by elastic-plastic analysis using local mesh which is enough subdivided to realize small plastic zone around crack tip. The crack growth rate considering effect of plastic-induced crack closure is predicted by modified Paris' law in which the stress intensity factor range under cyclic loading is converted into the effective value by the crack opening level. Then, the local mesh is updated by new crack shape determined from crack growth rate. By repeating these processes, our developed method can provide us to simulate fatigue crack propagation with plastic-induced crack closure directly. Another method is simplified one that the effective stress intensity factor range is approximately determined by the relationship between the maximum stress intensity factor and crack opening level as a result of preanalysis using two-dimensional DNS. By comparison of experimental results, it can be confirmed that our developed methods predict propagation of surface crack in specimen under bending and tensile loading conditions.
Tamura, Fumihiko; Takahashi, Hiroki; Kamikubota, Norihiko*; Ito, Yuichi; Hayashi, Naoki
Proceedings of 16th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.149 - 152, 2019/07
Precise timing pulses from the timing system are necessary for acceleration of high intensity proton beams in the J-PARC accelerators. The existing timing system was developed during the construction period of the J-PARC. The system has been working well for more than ten years, however, the optical modules for the signal transfer from the central control building to the accelerators are discontinued already. Although we have spares of the optical devices, maintenance of the system will be difficult. Therefore, we are developing the next generation timing system for the J-PARC. We present the design of the system, preliminary test results, and future plans.
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：11 Percentile：43.44(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.
Ichimura, Takahito; Takahashi, Iku; Iwasa, Kaoru; Nozawa, Yoshihiko
JAEA-Technology 2017-037, 322 Pages, 2018/03
JAEA-Technology-2017-037.pdf:69.64MB
The facility construction of the Okuma Analysis and Research Center is being promoted on the basis of the first phase facilities and the second stage facilities in accordance with the road map prescribed by the government in order to promote the decommissioning of the Fukushima Daiichi Nuclear Power Station is there. As the first phase facility, we designed "Radioactive Material Analyses and Research Facility Laboratory-1" which analyses mainly low-medium radiation doses radioactive waste (rabble, logging tree (incineration ash), dismantled waste etc), "Administrative Building" which is an office building, Site decontamination, Exterior and Utility equipment, etc. In addition to radiation protection and prevention of pollution at the time of construction, it is designed to reduce radiation exposure from outdoor pollution sources of residents after the facility starts to operate, shielding for the reliability of the analysis results, suppression and prevention of outside air inflow, etc.
Sawabe, Yuki*; Ishiyama, Tatsuya; Takahashi, Daisuke; Kato, Yuko; Suzuki, Takahiro*; Hirano, Koichiro; Takei, Hayanori; Meigo, Shinichiro; Kikuzawa, Nobuhiro; Hayashi, Naoki
Proceedings of 13th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.647 - 651, 2016/11
In the J-PARC, a 3 MeV linac has been developed for the tests of beam scraper irradiation and charge exchange by high-power laser. To accomplish tests efficiently and safely, the control system for 3 MeV was designed and developed, and this system consists of four subsystems, personal protection system, machine protection system, timing system, and remote control system using the EPICS. In this paper, the details of control system for a 3 MeV linac are presented.
Okumura, Yoshikazu; Gobin, R.*; Knaster, J.*; Heidinger, R.*; Ayala, J.-M.*; Bolzon, B.*; Cara, P.*; Chauvin, N.*; Chel, S.*; Gex, D.*; et al.
Review of Scientific Instruments, 87(2), p.02A739_1 - 02A739_3, 2016/02
Times Cited Count：8 Percentile：36.12(Instruments & Instrumentation)IFMIF is an accelerator based neutron facility having two set of linear accelerators each producing 125mA/CW deuterium ion beams (250mA in total) at 40MeV. The LIPAc (Linear IFMIF Prototype Accelerator) being developed in the IFMIF-EVEDA project consists of an injector, a RFQ accelerator, and a part of superconducting Linac, whose target is to demonstrate 125mA/CW deuterium ion beam acceleration up to 9MeV. The injector has been developed in CEA Saclay and already demonstrated 140mA/100keV deuterium beam. The injector was disassembled and delivered to the International Fusion Energy Research Center (IFERC) in Rokkasho, Japan, and the commissioning has started after its reassembly 2014; the first beam production has been achieved in November 2014. Up to now, 100keV/120mA/CW hydrogen ion beam has been produced with a low beam emittance of 0.2 
.mm.mrad (rms, normalized).
Okumura, Yoshikazu; Ayala, J.-M.*; Bolzon, B.*; Cara, P.*; Chauvin, N.*; Chel, S.*; Gex, D.*; Gobin, R.*; Harrault, F.*; Heidinger, R.*; et al.
Proceedings of 12th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.203 - 205, 2015/09
Under the framework of Broader Approach (BA) agreement between Japan and Euratom, IFMIF/EVEDA project was launched in 2007 to validate the key technologies to realize IFMIF. The most crucial technology to realize IFMIF is two set of linear accelerator each producing 125mA/CW deuterium ion beams up to 40MeV. The prototype accelerator, whose target is 125mA/CW deuterium ion beam acceleration up to 9MeV, is being developed in International Fusion Research Energy Center (IFERC) in Rokkasho, Japan. The injector developed in CEA Saclay was delivered in Rokkasho in 2014, and is under commissioning. Up to now, 100keV/120mA/CW hydrogen ion beams and 100keV/90mA/CW duty deuterium ion beams are successfully produced with a low beam emittance of 0.21 .mm.mrad (rms, normalized). Delivery of RFQ components will start in 2015, followed by the installation of RF power supplies in 2015.
