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Ishii, Katsunori; Aoki, Takeshi; Isaka, Kazuyoshi; Noguchi, Hiroki; Shimizu, Atsushi; Sato, Hiroyuki
Proceedings of 30th International Conference on Nuclear Engineering (ICONE30) (Internet), 9 Pages, 2023/05
Nomoto, Yasunobu; Mizuta, Naoki; Morita, Keisuke; Aoki, Takeshi; Okita, Shoichiro; Ishii, Katsunori; Kurahayashi, Kaoru; Yasuda, Takanori; Tanaka, Masato; Isaka, Kazuyoshi; et al.
Proceedings of 30th International Conference on Nuclear Engineering (ICONE30) (Internet), 7 Pages, 2023/05
Mizuta, Naoki; Morita, Keisuke; Aoki, Takeshi; Okita, Shoichiro; Ishii, Katsunori; Kurahayashi, Kaoru; Yasuda, Takanori; Tanaka, Masato; Isaka, Kazuyoshi; Noguchi, Hiroki; et al.
Proceedings of 30th International Conference on Nuclear Engineering (ICONE30) (Internet), 6 Pages, 2023/05
Kobayashi, Aine*; Toyama, Takeshi*; Nakamura, Takeshi*; Shobuda, Yoshihiro; Ishii, Koji*; Tomizawa, Masahito*; Takeuchi, Yasunao*; Sato, Yoichi*
Proceedings of 19th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.19 - 23, 2023/01
In the J-PARC main ring, density modulation due to longitudinal beam instability occurs during the debunching process of coasting beams. This leads to the generation of an electron cloud, which in turn causes transverse beam instabilities. The transverse beam instability causes beam loss and the electron cloud is assumed to cause vacuum degradation, both of which hinder the beam intensity enhancement, so it is essential to clarify the causes and countermeasures. In particular, the longitudinal impedance of several hundred MHz has been investigated as relevant, and measures to reduce the impedance of individual devices are underway. The Eddy-current type septum magnet, newly installed this year, was found to have a large impedance by simulation. Therefore, we are investigating a method to reduce the impedance by a flange loaded with SiC radio wave absorber, which can be applied to locations where there is no spatial margin to install a taper. In this report, we will discuss the characterization of SiC to be used in actual devices, impedance simulation reflecting the results of SiC evaluation, and evaluation of the effect of impedance countermeasures by impedance measurement using the wire method, and progress in evaluating the effect on the beam by beam simulation and beam study.
Kusano, Kanya*; Ichimoto, Kiyoshi*; Ishii, Mamoru*; Miyoshi, Yoshizumi*; Yoden, Shigeo*; Akiyoshi, Hideharu*; Asai, Ayumi*; Ebihara, Yusuke*; Fujiwara, Hitoshi*; Goto, Tadanori*; et al.
Earth, Planets and Space (Internet), 73(1), p.159_1 - 159_29, 2021/12
Times Cited Count:6 Percentile:51.19(Geosciences, Multidisciplinary)The PSTEP is a nationwide research collaboration in Japan and was conducted from April 2015 to March 2020, supported by a Grant-in-Aid for Scientific Research on Innovative Areas from the Ministry of Education, Culture, Sports, Science and Technology of Japan. It has made a significant progress in space weather research and operational forecasts, publishing over 500 refereed journal papers and organizing four international symposiums, various workshops and seminars, and summer school for graduate students at Rikubetsu in 2017. This paper is a summary report of the PSTEP and describes the major research achievements it produced.
Kobayashi, Aine*; Toyama, Takeshi*; Nakamura, Takeshi*; Shobuda, Yoshihiro; Ishii, Koji*
Proceedings of 18th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.287 - 291, 2021/10
no abstracts in English
Takahama, Ryusei*; Ishii, Toi*; Indo, Daigo*; Arizono, Mitsutoshi*; Terakura, Chieko*; Tokura, Yoshinori*; Takeshita, Nao*; Noda, Masaaki*; Kuwahara, Hideki*; Saiki, Takuo*; et al.
Physical Review Materials (Internet), 4(7), p.074401_1 - 074401_11, 2020/07
Times Cited Count:9 Percentile:40.15(Materials Science, Multidisciplinary)Hama, Katsuhiro; Mizuno, Takashi; Sasao, Eiji; Iwatsuki, Teruki; Saegusa, Hiromitsu; Sato, Toshinori; Fujita, Tomoo; Sasamoto, Hiroshi; Matsuoka, Toshiyuki; Yokota, Hideharu; et al.
JAEA-Research 2015-007, 269 Pages, 2015/08
We have synthesised the research results from Mizunami/Horonobe URLs and geo-stability projects in the second mid-term research phase. It could be used as technical bases for NUMO/Regulator in each decision point from sitting to beginning of disposal (Principal Investigation to Detailed Investigation Phase). High quality construction techniques and field investigation methods have been developed and implemented and these will be directly applicable to the National Disposal Program (along with general assessments of hazardous natural events and processes). It will be crucial to acquire technical knowledge on decisions of partial backfilling and final closure by actual field experiments in Mizunami/Horonobe URLs as main themes for the next phases.
Takahashi, Ryuichi*; Ishimaru, Yasuhiro*; Shimo, H.*; Bashir, K.*; Senoura, Takeshi*; Sugimoto, Kazuhiko*; Ono, Kazuko*; Suzui, Nobuo; Kawachi, Naoki; Ishii, Satomi; et al.
PLOS ONE (Internet), 9(6), p.e98816_1 - e98816_7, 2014/06
Times Cited Count:51 Percentile:86.7(Multidisciplinary Sciences)Shibata, Masahiro; Sawada, Atsushi; Tachi, Yukio; Makino, Hitoshi; Hayano, Akira; Mitsui, Seiichiro; Taniguchi, Naoki; Oda, Chie; Kitamura, Akira; Osawa, Hideaki; et al.
JAEA-Research 2012-032, 298 Pages, 2012/09
JAEA and NUMO have conducted a collaborative research work which is designed to enhance the methodology of repository design and performance assessment in preliminary investigation phase. The topics and the conducted research are follows; (1) Study on selection of host rock: in terms of hydraulic properties, items for assessing rock property, and assessment methodology of groundwater travel time has been organized with interaction from site investigation. (2) Study on development of scenario: the existing approach has been embodied, in addition, the phenomenological understanding regarding dissolution of and nuclide release from vitrified waste, corrosion of the overpack, long-term performance of the buffer are summarized. (3) Study on setting nuclide migration parameters: the approach for parameter setting has been improved for sorption and diffusion coefficient of buffer/rock, and applied and tested for parameter setting of key radionuclides. (4) Study on ensuring quality of knowledge: framework for ensuring quality of knowledge has been studied and examined aimed at the likely disposal facility condition.
Sakai, Hiroshi*; Umemori, Kensei*; Takahashi, Takeshi*; Furuya, Takaaki*; Shinoe, Kenji*; Ishii, Atsushi*; Sawamura, Masaru; Muto, Toshiya*
Proceedings of 7th Annual Meeting of Particle Accelerator Society of Japan (DVD-ROM), p.173 - 176, 2010/08
We are developing the superconducting (SC) cavity for Energy Recovery Linac (ERL) in Japan. In order to survey the electron emission and the heating spot of the cavity inner surface in detail, cavity diagnostics with the rotating mapping system was applied. Two types of sensors, one of which was the carbon resistor and the other was the Si PIN photo diode, were set to detect the temperature rise and electron emission. By rotating the sensor arrays around the cavity axis, a lot of information was obtained all over the cavity surface in detail. This paper reports the results of vertical tests by using this rotating mapping system with the single-cell and 9-cell Nb ERL cavity.
Wei, G.; Koseki, Tadashi*; Tomizawa, Masahito*; Igarashi, Susumu*; Ishii, Koji*; Ando, Ainosuke; Takano, Jumpei*; Uota, Masahiko*; Fan, K.*; Hatakeyama, Shuichiro; et al.
Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.3918 - 3920, 2010/05
Sakai, Hiroshi*; Furuya, Takaaki*; Sakanaka, Shogo*; Takahashi, Takeshi*; Umemori, Kensei*; Ishii, Atsushi*; Nakamura, Norio*; Shinoe, Kenji*; Sawamura, Masaru
Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.2953 - 2955, 2010/05
We started to develop an input power coupler for a 1.3 GHz ERL superconducting cavity for main linac. We fabricated power coupler components such as ceramic windows and bellows and carried out the high-power test of the components by using a CW 30 kW IOT power source. During this test, the ceramic window was broken by the sudden heat load. We found that this heat load occurred by the unexpected dipole mode. We renewed the ceramic window and successfully carried out the high power test up to CW 27 kW input power.
Sakai, Hiroshi*; Umemori, Kensei*; Sakanaka, Shogo*; Takahashi, Takeshi*; Furuya, Takaaki*; Shinoe, Kenji*; Ishii, Atsushi*; Nakamura, Norio*; Sawamura, Masaru
Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.866 - 868, 2010/03
We started to develop an input coupler for a 1.3 GHz ERL superconducting cavity. Required input power is about 20 kW for the cavity acceleration field of 20 MV/m and the beam current of 100 mA in energy recovery operation. The input coupler is designed based on the STF-BL input coupler and some modifications are applied to the design for the CW 20 kW power operation. We fabricated input coupler components such as ceramic windows and bellows and carried out the high-power test of the components by using a 30 kW IOT power source and a test stand constructed for the high-power test. In this report, we mainly describe the results of the high-power test of ceramic window and bellows.
Makino, Takahiro; Kobayashi, Daisuke*; Hirose, Kazuyuki*; Takahashi, Daisuke*; Ishii, Shigeru*; Kusano, Masaki*; Onoda, Shinobu; Hirao, Toshio; Oshima, Takeshi
IEEE Transactions on Nuclear Science, 56(6), p.3180 - 3184, 2009/12
Times Cited Count:13 Percentile:64.74(Engineering, Electrical & Electronic)SET-induced soft-error rates (s) of logic LSIs are estimated from SET pulse-widths measured in logic cells used in logic LSIs. The estimated rates are consistent with directly measured s for logic LSIs.
Sakai, Hiroshi*; Furuya, Takaaki*; Sakanaka, Shogo*; Takahashi, Takeshi*; Umemori, Kensei*; Ishii, Atsushi*; Nakamura, Norio*; Shinoe, Kenji*; Sawamura, Masaru
Proceedings of 14th International Conference on RF Superconductivity (SRF 2009) (Internet), p.684 - 688, 2009/09
We started to develop an input coupler for a 1.3GHz ERL superconducting cavity for ERL main linac. Required input power is about 20kW for the cavity acceleration field of 20MV/m and the beam current of 100mA in energy recovery operation. The input coupler is designed based on the STF-BL input coupler and some modifications are applied for the CW 20kW power operation. We fabricated input coupler components such as ceramic windows and bellows and carried out the high-power test of the components by using a 30kW IOT power source and a test stand constructed.
Makino, Takahiro*; Kobayashi, Daisuke*; Hirose, Kazuyuki*; Yanagawa, Yoshimitsu*; Saito, Hirobumi*; Ikeda, Hirokazu*; Takahashi, Daisuke*; Ishii, Shigeru*; Kusano, Masaki*; Onoda, Shinobu; et al.
IEEE Transactions on Nuclear Science, 56(1), p.202 - 207, 2009/02
Times Cited Count:36 Percentile:90.64(Engineering, Electrical & Electronic)SET pulse-widths were measured as a function of LET by using pulse capture circuits and were simulated with mixed-mode 3-D device simulations. We found that the carrier recombination process dominates LET dependence of SET pulse-widths.
Ishii, Eiichi; Yasue, Kenichi; Ohira, Hiroto*; Furusawa, Akira*; Hasegawa, Takeshi*; Nakagawa, Mitsuhiro*
Chishitsugaku Zasshi, 114(6), p.286 - 299, 2008/06
no abstracts in English
Sakanaka, Shogo*; Ago, Tomonori*; Enomoto, Atsushi*; Fukuda, Shigeki*; Furukawa, Kazuro*; Furuya, Takaaki*; Haga, Kaiichi*; Harada, Kentaro*; Hiramatsu, Shigenori*; Honda, Toru*; et al.
Proceedings of 11th European Particle Accelerator Conference (EPAC '08) (CD-ROM), p.205 - 207, 2008/06
Future synchrotron light sources based on the energy-recovery linacs (ERLs) are expected to be capable of producing super-brilliant and/or ultra-short pulses of synchrotron radiation. Our Japanese collaboration team is making efforts for realizing an ERL-based hard X-ray source. We report recent progress in our R&D efforts.
Makino, Takahiro*; Yanagawa, Yoshimitsu*; Kobayashi, Daisuke*; Fukuda, Seisuke*; Hirose, Kazuyuki*; Ikeda, Hirokazu*; Saito, Hirobumi*; Onoda, Shinobu; Hirao, Toshio; Oshima, Takeshi; et al.
Shingaku Giho, 108(100), p.67 - 72, 2008/06
SET pulse-widths were measured as a function of LET by using pulse capture circuits. In addition, a scan flip-flop (FF) is designed to observe both single event transient (SET) and single event upset (SEU) soft errors in logic VLSI system.