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

https://doi.org/10.1080/00223131.2022.2038301

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.

Evaluation of particulate Cs discharge from a mountainous forested catchment using reservoir sediments and sinking particles

Funaki, Hironori; Yoshimura, Kazuya; Sakuma, Kazuyuki; Iri, Shatei; Oda, Yoshihiro

Journal of Environmental Radioactivity, 189, p.48 - 56, 2018/09

https://doi.org/10.1016/j.jenvrad.2018.03.004

Predicting the long-term Cs distribution in Fukushima after the Fukushima Dai-ichi Nuclear Power Plant accident; A Parameter sensitivity analysis

Yamaguchi, Masaaki; Kitamura, Akihiro; Oda, Yoshihiro; Onishi, Yasuo*

Journal of Environmental Radioactivity, 135, p.135 - 146, 2014/09

https://doi.org/10.1016/j.jenvrad.2014.04.011

We applied a model, to predict long term cesium distribution on Fukushima area, based on the USLE and simple sediment discharge formulas. Sensitivity analysis was conducted here to narrow the range of the output results due to the uncertainties of parameters. The preliminary calculation indicated significant deposition of sand portion within river basins. On the other hand the most of the eroded silt and clay portions were transported downstream to the river mouths. Annual sediment outflow into the ocean from Abukuma River and its total from the other 13 river basins vary between calculation cases based on the variation of land use, landform or precipitation. On the other hand, contributions of those parameters are relatively small for Cs concentration within transported soil. This indicates the total amount of Cs outflow into the ocean could be controlled by amount of soil erosion and transport, and total amount of Cs remaining within the basin.

Suppression of heavy-ion induced current in SOI device

Ogura, Shunta*; Komiyama, Takahiro*; Takahashi, Yoshihiro*; Makino, Takahiro; Onoda, Shinobu; Hirao, Toshio*; Oshima, Takeshi

Proceedings of 10th International Workshop on Radiation Effects on Semiconductor Devices for Space Applications (RASEDA-10) (Internet), p.127 - 129, 2012/12

We have investigated the transient current in a SOI pn junction diode induced by single heavy-ions. The amount of radiation induced total collected charge exceeds the generated charge in active SOI layer because some of generated charge in handle substrate is collected through a BOX layer by displacement current. The displacement current is caused by the charges collected at surface of handle substrate due to an electric field in depletion layer. In this paper, we show that the amount of collected charge can be suppressed by reducing the width of depletion layer at the surface of handle substrate.

X-ray study of radiation damage in UO irradiated with high-energy heavy ions

Ishikawa, Norito; Sonoda, Takeshi*; Okamoto, Yoshihiro; Sawabe, Takashi*; Takegahara, Keisuke; Kosugi, Shinya*; Iwase, Akihiro*

Journal of Nuclear Materials, 419(1-3), p.392 - 396, 2011/12

https://doi.org/10.1016/j.jnucmat.2011.08.013

In order to characterize the radiation damage due to ion-track formation in UO, polycrystalline samples have been irradiated with 210-MeV Xe ions, and measured with XRD (X-ray diffraction) technique using Cu X-ray. We have also tried EXAFS (extended X-ray absorption fine structure) measurement using X-ray near U L-edge. The results show that XRD technique detects damage at relatively low fluence of 10 ions/m and higher, while the irradiation-induced change of EXAFS spectra is not observed even at highest fluence of 10 ions/m. The damage detection may be critically influenced by the depth profile of X-ray penetration.

Research and development for treatment and disposal technologies of TRU waste; JFY 2009 annual report

Kamei, Gento; Honda, Akira; Mihara, Morihiro; Oda, Chie; Ichige, Satoru; Kurimoto, Yoshitaka; Hoshino, Seiichi; Akagi, Yosuke; Sato, Nobuyuki; Murakami, Hiroshi*; et al.

JAEA-Research 2011-002, 82 Pages, 2011/03

JAEA-Research-2011-002.pdf:5.64MB

Based on Japanese governmental policy and general scheme, research and development of geological disposal technology for TRU waste has been proceeding to improve reliability of the safety assessment of the co-locational disposal of TRU waste and of HLW, to expand the basement of generic safety assessment, and to develop the alternative technology to cope with the broad geologic environment of Japan. Japan Atomic Energy Agency is dealing with the assignments in the governmental generic scheme. We report here the progress of the studies at the end of H20 (2008) Japanese fiscal year, which are (1) evaluation of long-term mechanical stability in the near-field including development of a creep mode of rock and analyses of mechanical behavior of TRU waste repository, (2) performance assessment of the disposal system including data acquisition and preparation on radionuclides migration, cementitious material alteration, bentonite and hostrock alteration with alkaline solution and nitrate effect, and (3) alternative technology development including decomposition of nitrate.

Isolation and characterization of suppressors of the in

Natsui, Yu*; Nefissi, R.*; Miyata, Kana*; Oda, Atsushi*; Hase, Yoshihiro; Nakagawa, Mayu*; Mizoguchi, Tsuyoshi*

Plant Biotechnology, 27(5), p.463 - 468, 2010/12

https://doi.org/10.5511/plantbiotechnology.10.0722a

EARLY FLOWERING 3 (ELF3) is a circadian clock protein with a major role in maintaining circadian rhythms in plants. In this work, was mutagenized by EMS in plants of the Lansberg background to isolate suppressors of and to understand the molecular mechanisms of flowering time controlled by ELF3. Two suppressors, obtained from this screen and from a precious study, were chosen for further analysis. Genetic mapping, gene expression analysis, and sequencing identified and as new alleles of and , respectively. Genetic interactions between and and between and in the control of the floral activator were also investigated. Six suppressor of were classified at least into four subgroups based on the expression of such floral regulators as GI, CO, FT, SVP, and FLC, and on their flowering times under LL, LD, and SD. This classification scheme is useful for the characterization of unidentified suppressor mutations.

Heavy-ion induced current in SOI junction diode

Takahashi, Yoshihiro*; Takeyasu, Hidenori*; Okazaki, Yuji*; Hirao, Toshio; Onoda, Shinobu; Oshima, Takeshi

Proceedings of 9th International Workshop on Radiation Effects on Semiconductor Devices for Space Applications (RASEDA-9), p.173 - 175, 2010/10

no abstracts in English

Study on flow and mass transport through fractured sedimentary rocks, 3

Shimo, Michito*; Kumamoto, So*; Ito, Akira*; Karasaki, Kenji*; Sawada, Atsushi; Oda, Yoshihiro; Sato, Hisashi

JAEA-Research 2009-060, 70 Pages, 2010/03

JAEA-Research-2009-060.pdf:14.26MB

It is important for safety assessment of HLW geological disposal to evaluate groundwater flow and mass transport in deep underground appropriately. Though it is considered that the mass transport in sedimentary rock occurs in pores between grains mainly, fractures of sedimentary rock can be main paths. In this study the following three tasks were carried out: (1) laboratory hydraulic and tracer experiments using the rock cores of Wakkanai formation, (2) a study on the tracer test and sampling technique for the larger scale, (3) a study on the reduction technique of uncertainty of the hydrogeological models using data from surface-based investigation. On the block scale tracer test technique, the sampling technique using wire saw and tracer test technique using block samples were suggested. As for the reduction technique of uncertainty of the hydrogeological model, availability of the information other than pressure data, such as the temperature and salinity and all, were presented.

Change in ion beam induced current from Si metal-oxide-semiconductor capacitors after -ray irradiation

Oshima, Takeshi; Onoda, Shinobu; Hirao, Toshio; Takahashi, Yoshihiro*; Vizkelethy, G.*; Doyle, B. L.*

AIP Conference Proceedings 1099, p.1014 - 1017, 2009/03

https://doi.org/10.1063/1.3119985

Metal-Oxide-Semiconductor (MOS) capacitors were made on both n- and p-type Si substrates (n-MOS, and p-MOS). These MOS capacitors were irradiated with -rays at a dose of 6.3 kGy (SiO) at room temperature. The capacitance-voltage characteristics for MOS capacitors were measured before and after irradiation. The flat band shift for n-MOS and p-MOS capacitors due to -ray irradiation was -12.3 V and -15.2 V, respectively. As for the generation of interface traps, the values for n-MOS and p-MOS capacitors were estimated to be 0.510 and 1.710/cm, respectively. Transient Ion Beam Induced Current (TIBIC) obtained from these MOS capacitors were compared before and after -ray irradiation. For n-MOS capacitors, the peak height of TIBIC signals decreased after -ray irradiation. On the other hand, the peak height of TIBIC signals for p-MOS capacitors increased after -ray irradiation. The applied bias dependence of the peak height of TIBIC signals for MOS capacitors irradiated with -rays can be matched to that for ones before -rays irradiation by shifting the voltage by -13 V for n-MOS capacitors and by -15 V for p-MOS capacitors. These voltage values are in good agreement with the flat band voltage shifts due to -ray irradiation. Since flat band shift occurs due to the generation of positive charge trapped in gate oxide, the change in TIBIC signals observed for MOS capacitors due to -ray irradiation can be interpreted in terms of positive charge generated in oxide.