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Kondo, Yasuhiro; Chimura, Motoki; Cicek, E.*; Fukui, Yuji*; Futatsukawa, Kenta*; Fuwa, Yasuhiro; Goto, Rikuto*; Hirano, Koichiro; Ishikawa, Masaki*; Ito, Takashi; et al.
Proceedings of 22nd Annual Meeting of Particle Accelerator Society of Japan (Internet), p.124 - 129, 2026/03
Various upgrade plans of the J-PARC linac are underway, and repetition-rate doubling project is one of the most important part. Currently, the linac supplies a 400~MeV H
ion beam to the 3~GeV synchrotron (RCS) at a repetition rate of 25~Hz. However, to deliver the beam to both RCS and proton-beam irradiation facility under planning, it is necessary to raise the repetition rate from 25~Hz to 50~Hz. Prior to construction of the beamline to the irradiation facility, we conducted a verification of the 50~Hz operation of all the linac apparatus simultaneously within the current operational limits in May 2025. And also, the verification of the 50~Hz operation of the particle counter system, which is one of the most important safety device of the J-PARC accelerator, was conducted. As a result, any significant problems were not found out, and it is now ready for the upcoming 50~Hz-beam acceleration demonstration. This paper describes this details of the demonstration of the 50~Hz operation, without beam acceleration, of the J-PARC linac.
Liu, Y.*; Otani, Masashi*; Miyao, Tomoaki*; Nakazawa, Yuga*; Shibata, Takanori*; Nammo, Kesao*; Fang, Z.*; Futatsukawa, Kenta*; Fukui, Yuji*; Mizobata, Satoshi*; et al.
Proceedings of 16th International Particle Accelerator Conference (IPAC25) (Internet), p.855 - 857, 2025/11
Kondo, Yasuhiro; Kitamura, Ryo; Fuwa, Yasuhiro; Morishita, Takatoshi; Moriya, Katsuhiro; Takayanagi, Tomohiro; Otani, Masashi*; Cicek, E.*; Ego, Hiroyasu*; Fukao, Yoshinori*; et al.
Proceedings of 31st International Linear Accelerator Conference (LINAC 2022) (Internet), p.636 - 641, 2022/09
The muon linac project for the precise measurement of the muon anomalous magnetic and electric dipole moments, which is currently one of the hottest issues of the elementary particle physics, is in progress at J-PARC. The muons from the J-PARC muon facility are once cooled to room temperature, then accelerated up to 212 MeV with a normalized emittance of 1.5 
mm mrad and a momentum spread of 0.1%. Four types of accelerating structures are adopted to obtain the efficient acceleration with a wide beta range from 0.01 to 0.94. The project is moving into the construction phase. We already demonstrated the re-acceleration scheme of the decelerated muons using a 324-MHz RFQ in 2017. The high-power test of the 324-MHz Interdigital H-mode (IH) DTL using a prototype cavity was performed in 2021. The fabrication of the first module of 14 modules of the 1296-MHz Disk and Washer (DAW) CCL will be done to confirm the production process. Moreover, the final design of the travelling wave accelerating structure for the high beta region is also proceeding. In this paper, the recent progress toward the realization of the world first muon linac will be presented.
Okabe, Kota; Liu, Y.*; Otani, Masashi*; Moriya, Katsuhiro; Shibata, Takanori*; Chimura, Motoki*; Hirano, Koichiro; Oguri, Hidetomo; Kinsho, Michikazu
JPS Conference Proceedings (Internet), 33, p.011011_1 - 011011_6, 2021/03
To realize more stable operation of the J-PARC accelerators, we have a re-design plan of an MEBT1 (Medium Energy Beam Transport). At the J-PARC Linac, the MEBT1 has transverse and longitudinal beam matching section for the DTLs. However there are some locally activated spots in DTL area at the current beam power level. To reduce beam loss during a beam acceleration at the DTLs is a most important task for a stable user operation. The first thing we should do is investigation a connection between beam quality in the MEBT1 and parameters of the upstream hardware. In this presentation, we will report a high intensity beam study results at the MEBT1.
beam with 3 MeV using the carbon materialKitamura, Ryo; Futatsukawa, Kenta*; Hayashi, Naoki; Hirano, Koichiro; Kosaka, Satoshi*; Miyao, Tomoaki*; Moriya, Katsuhiro; Nemoto, Yasuo*; Oguri, Hidetomo
Proceedings of 16th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.51 - 54, 2019/07
The longitudinal measurement and tuning at the beam transport after the RFQ are important to reduce the beam loss and the emittance growth in the J-PARC linac, when the high-intensity H beam of more than 60 mA is supplied. The new bunch shape monitor (BSM) using the carbon-nanotube (CNT) wire is necessary to measure the bunch shape of the high-intensity H beam with 3 MeV, because the CNT wire has a high-temperature tolerance and a small energy deposit. However, when the high voltage was applied to the CNT wire to extract the secondary electron derived, the discharge prevents the power supply from applying the voltage. Therefore, the discharge should be suppressed to measure the bunch shape with stability. Considering the characteristics of the CNT as the emitter, when the length of the CNT wire was short, the high voltage of -10 kV was applied to the CNT wire. The current status and future prospects of the BSM using the CNT wire are reported in this presentation.
Kitamura, Ryo; Hayashi, Naoki; Hirano, Koichiro; Kondo, Yasuhiro; Moriya, Katsuhiro; Oguri, Hidetomo; Futatsukawa, Kenta*; Miyao, Tomoaki*; Otani, Masashi*; Kosaka, Satoshi*; et al.
Proceedings of 10th International Particle Accelerator Conference (IPAC '19) (Internet), p.2543 - 2546, 2019/06
A bunch shape monitor (BSM) is one of the important instruments to measure the longitudinal phase space distribution. For example in the J-PARC linac, three BSMs using the tungsten wire are installed at the ACS section to measure the bunch shapes between the accelerating cavities. However, this conventional BSM is hard to measure the bunch shape of H beam with 3 MeV at the beam transport between the RFQ and DTL sections, because the wire is broken around the center region of the beam. The new BSM using the carbon-nano-tube (CNT) wire is being developed to be able to measure the bunch shape of the H beam with 3 MeV. The careful attention should be paid to apply the high voltage of 
10 kV to the CNT wire. The several measures are taken to suppress the discharge from the wire and operate the CNT-BSM. This presentation reports the current status of the development and future prospective for the CNT-BSM.
Shibata, Masahiro; Sawada, Atsushi; Tachi, Yukio; Makino, Hitoshi; Wakasugi, Keiichiro; Mitsui, Seiichiro; Kitamura, Akira; Yoshikawa, Hideki; Oda, Chie; Ishidera, Takamitsu; et al.
JAEA-Research 2014-030, 457 Pages, 2015/03
JAEA-Research-2014-030.pdf:199.23MB
JAEA and NUMO have conducted a collaborative research work which is designed to enhance the methodology of repository design and post-closure performance assessment in preliminary investigation stage. With regard to (1) study on rock suitability in terms of hydrology, based on some examples of developing method of hydro-geological structure model, acquired knowledge are arranged using the tree diagram, and model uncertainty and its influence on the evaluation items were discussed. With regard to (2) study on scenario development, the developed approach for "defining conditions" has been reevaluated and improved from practical viewpoints. In addition, the uncertainty evaluation for the effect of use of cementitious material, as well as glass dissolution model, was conducted with analytical evaluation. With regard to (3) study on setting radionuclide migration parameters, based on survey of precedent procedures, multiple-approach for distribution coefficient of rocks was established, and the adequacy of the approach was confirmed though its application to sedimentary rock and granitic rock. Besides, an approach for solubility setting was developed including the procedure of selection of solubility limiting solid phase. The adequacy of the approach was confirmed though its application to key radionuclides.
Koarashi, Jun; Moriya, Koichi*; Atarashi-Andoh, Mariko; Matsunaga, Takeshi; Fujita, Hiroki; Nagaoka, Mika
Scientific Reports (Internet), 2, p.1005_1 - 1005_5, 2012/12
Times Cited Count：42 Percentile：68.19(Multidisciplinary Sciences)The fate of 
Cs derived from the Fukushima nuclear accident fallout and associated radiological hazards are largely dependent on its mobility in the surface soils of forest ecosystems. Thus, we quantified microbial and adsorptive retentions of Cs in forest surface (0-3 cm) soils. The K
SO
extraction process liberated 2.1%-12.8% of the total Cs from the soils. Two soils with a higher content of clay- and silt-sized particles, organic carbon content, and cation exchange capacity showed higher Cs extractability. Microbial biomass was observed in all of the soils. However, the Cs extractability did not increase after destruction of the microbial biomass by chloroform fumigation, providing no evidence for microbial retention of the Fukushima-fallout Cs. The results indicate that uptake of Cs by soil microorganisms is less important for retention of potentially mobile Cs in the forest surface soils compared to ion-exchange adsorption on non-specific sites provided by abiotic components.
Kono, Takahiko; Ogino, Haruyuki*; Yoshitomi, Hiroshi; Fujiwara, Keiko*; Moriya, Koichi*
FBNews, (410), p.7 - 12, 2011/02
no abstracts in English
Tokiwa, Tetsuya; Asamori, Koichi; Hiraga, Naoto*; Yamada, Osamu; Moriya, Hirokazu*; Hotta, Hikaru*; Kitamura, Itaru*; Yokota, Hideharu
Proceedings of 13th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM 2010) (CD-ROM), p.117 - 122, 2010/10
In this paper, we discuss the relationship between the accurate hypocentral distribution and 3-D geological structure in and around the Horonobe area, Japan. We carried out multiplet-clustering analysis by using data of the 421 micro-earthquakes which occurred from 1st September, 2003 to 30th September, 2007. The 3-D geological structure model was mainly constructed from previous seismic reflection profiles and drilling data. As a result of this analysis, although there are some differences in depth between them, the hypocenters are distributed in NNW-SSE direction and become deeper from the west toward the east. The distributed pattern of the hypocenters is similar to the one of the geological structure. These results indicate that the hypocentral distribution may represent existence of active zone related to the geological structure, and provide effective information which can contribute to establishing methods for estimating the future evolution of the geological environment.
derived from soil organic matter decomposition over the incubation timeMoriya, Koichi*; Moriizumi, Jun*; Yamazawa, Hiromi*; Koarashi, Jun; Atarashi-Andoh, Mariko
KURRI-KR-153, p.53 - 59, 2010/03
To understand the decomposition mechanism in the soil, we researched the relationship between compositions of SOM and CO derived from SOM decomposition (SOMD-CO) by using 
C and 
C. With the soil incubation, we measured CO production rates of soil and carbon isotopic ratios in SOMD-CO. The CO production rates decreased rapidly at the beginning of incubation, and then decreased slowly. On the other hand, 
C
before incubation was larger than C
. After 40-70 days of incubation, C became smaller than C, and then C after 120-170 days approached C. We consider these results as follows. SOM is composed of three components, rapidly decomposable SOM that has large C, slowly decomposable SOM that has small C and passive SOM that has the same value as C. With the progress of soil decomposition, the dominant component in SOMD-CO changed. Therefore, C changed too.
Nohara, Tsuyoshi; Umeda, Koji; Sasao, Eiji; Asamori, Koichi; Hanamuro, Takahiro; Moriya, Toshifumi*; Nakatsuka, Noboru
JAEA-Research 2007-087, 102 Pages, 2008/02
JAEA-Research-2007-087.pdf:35.58MB
The Japanese islands are located in the tectonically active Circum-Pacific Mobile Belt. As a result, Japan has a high frequency of earthquakes and eruptions. Special consideration is given to the long-term stability of the geological environment, taking into account volcanism, faulting, uplift, denudation, climatic change and sea-level change in Japan. Development of research/prediction technologies for geotectonic events has been carried out to evaluate the long-term stability of the geological environment in Japan. Until fiscal year 2005, to confirm existence of phenomena that have a influence on geological disposal system (e.g. active fault or Quarternary volcanoes) and to confirm that there was not the trace that the phenomena occurred in the past and to predict/evaluate possibility of the phenomena, development of the research/prediction techniques for geotectonic events (e.g. Research techniques for earthquake source faults, Research techniques for detecting magmas and high-temperature fluids, Three-dimensional landform development simulator) were carried out. This report describes our efforts of these technologies based on its R&D program until fiscal year 2005.
Nakatsuka, Noboru; Nohara, Tsuyoshi; Umeda, Koji; Moriya, Toshifumi; Asamori, Koichi; Niwa, Masakazu
Hoshasei Haikibutsu Anzen Kenkyu Nenji Keikaku (Heisei-13-Nendo
Heisei-17-Nendo) Kenkyu Seika Hokokushu, p.50 - 56, 2006/03
no abstracts in English
Tochiyama, Osamu*; Niibori, Yuichi*; Tanaka, Koichi*; Moriya, Yusuke*; Yui, Mikazu; Shibata, Masahiro; Tetsu, Takeshi*
JNC TY8400 2002-014, 129 Pages, 2002/05
JNC-TY8400-2002-014.pdf:2.35MB
None
Yokoi, Koichi*; Yoneda, Yoshihiro*; Takahara, Hiroyuki*; Moriya, Toshifumi*
PNC TJ1380 96-002, 68 Pages, 1996/03
None
Yokoi, Koichi*; Noguchi, Yoshifumi*; Morita, Masaya*; Nakamura, Naoaki*; Takahara, Hiroyuki*; Moriya, Toshifumi*
PNC TJ1380 95-004, 235 Pages, 1995/03
None
Cho, Hisashi*; Yokoi, Koichi*; Noguchi, Yoshifumi*; Morita, Masaya*; Nakamura, Naoaki*; Takahara, Hiroyuki*; Moriya, Toshifumi*
PNC TJ1380 94-001, 1308 Pages, 1994/03
None
Koarashi, Jun; Atarashi-Andoh, Mariko; Ishizuka, Shigehiro*; Kadono, Atsunobu*; Moriya, Koichi*; Nakanishi, Takahiro
no journal, ,
no abstracts in English
beam with 3 MeV using the carbon-nano tube wireKitamura, Ryo; Futatsukawa, Kenta*; Hayashi, Naoki; Hirano, Koichiro; Miyao, Tomoaki*; Moriya, Katsuhiro; Nemoto, Yasuo*; Oguri, Hidetomo
no journal, ,
no abstracts in English
beam with 3 MeV using the carbon-nano tube wireKitamura, Ryo; Futatsukawa, Kenta*; Hayashi, Naoki; Hirano, Koichiro; Miyao, Tomoaki*; Moriya, Katsuhiro; Nemoto, Yasuo*; Oguri, Hidetomo
no journal, ,
In the linac of the Japan Proton Accelerator Research Complex, the bunch shape monitor (BSM) is being developed to tune the longitudinal beam matching between the accelerating cavities. When the beam irradiates the tungsten (W) wire in the BSM, the secondary electrons are emitted and extracted to the BSM in order to measure the bunch size of the H beam. However, the W wire is less resistant to the high-intensity H beam from the RFQ. Therefore, the BSM using the Carbon-Nano Tube wire (CNT-BSM) has been developed. The discharge from the CNT wire is the problem for the operation. To suppress the discharge, the baking process was introduced. Then, we succeeded in applying the high voltage to the CNT wire without the discharge. The signal responses from the W and CNT wires are being tested using the thermal electrons. We will reports the current status of the development and future prospects.
