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Oishi, Kazuki*; Igarashi, Daisuke*; Tatara, Ryoichi*; Kawamura, Yukihiko*; Hiroi, Kosuke; Suzuki, Junichi*; Umegaki, Izumi*; Nishimura, Shoichiro*; Koda, Akihiro*; Komaba, Shinichi*; et al.
Journal of Physics; Conference Series, 2462, p.012048_1 - 012048_5, 2023/03
Times Cited Count：0 Percentile：0.2(Physics, Applied)Tani, Norio; Watanabe, Yasuhiro; Hotchi, Hideaki; Harada, Hiroyuki; Yamamoto, Masanobu; Kinsho, Michikazu; Igarashi, Susumu*; Sato, Yoichi*; Shirakata, Masashi*; Koseki, Tadashi*
Proceedings of 13th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.708 - 711, 2016/11
At the J-PARC Main Ring (MR), there have been various investigation carried out at the moment aiming at the beam operation of MW order. As one of the investigations, a study of the Rapid-Cycling Synchrotron (RCS) magnets was implemented. Increase of the extraction energy of RCS was needed to reduce beam loss, as beam loss in the MR injection region was large under influence of Space Charge effect at the injection beam of 3GeV. Therefore conceptual design of the extraction energy upgrade using dipole and quadrupole magnets of RCS was performed. In this paper, we will report the contents of the study in extraction energy upgrade of RCS magnets and problems which became clear as a result.
Harada, Hiroyuki; Hotchi, Hideaki; Igarashi, Susumu*; Sato, Yoichi*; Koseki, Tadashi
JPS Conference Proceedings (Internet), 8, p.012012_1 - 012012_6, 2015/09
The 240-kW output beam power in the J-PARC 50-GeV Main Ring (MR) has been achieved for the 30-GeV user operation with the cycle time of 2.48 sec and the injected beam intensity with the output beam power of 380-kW equivalent from 3-GeV Rapid Cycling Synchrotron (RCS). The target of output beam power in MR is 750-kW by faster cycling and the injected beam intensity of 600-kW equivalent beam from the RCS. The MR are developing the new type power supplies of the MR main magnets and the high-impedance core of the MR RF cavities. The RCS will aim the designed output beam power of 1-MW from the beam commissioning on October 2014 after the peak current upgrade of Linac from 30 to 50-mA. For higher beam power of MR, we have explored the accelerator options. As one of options, 8-GeV Booster Ring (BR) is also designed for increasing the injection energy of the MR. The increasement of injection energy leads to the reducing a space charge force and the increasing the acceptance clearance from the physical aperture of the MR. In this paper, the realistic injection and extraction system of the BR and the new injection system of the MR for Multi-MW output beam power are also described.
Hotchi, Hideaki; Harada, Hiroyuki; Yamamoto, Masanobu; Igarashi, Susumu*; Koseki, Tadashi*; Sato, Yoichi*
JPS Conference Proceedings (Internet), 8, p.012008_1 - 012008_6, 2015/09
Now the J-PARC accelerators (Linac, 3GeV RCS, 50GeV MR) are in transition from the initial beam commissioning phase to the final stage aiming for the design output beam power of 1 MW from RCS and 0.75 MW from MR; RCS is to start 1-MW beam tuning from October 2014 after completing the linac upgrade, and MR aims at 0.75 MW within the next 3 years by introducing new main magnet power supplies with the faster cycling time. In view of such current situation, we have started discussions for the future J-PARC accelerator concept toward a Multi-MW output beam power. In this paper, we discuss the feasibility for the introduction of a new 8-GeV booster synchrotron between RCS and MR as one possible option toward a Multi-MW output beam power from MR, in combination with the RCS beam power upgrade from 1 MW to 2 MW.
Harada, Hiroyuki; Meigo, Shinichiro; Shirakata, Masashi*; Sato, Yoichi*; Tamura, Fumihiko; Tejima, Masaki*; Hashimoto, Yoshinori*; Igarashi, Susumu*; Koseki, Tadashi
JPS Conference Proceedings (Internet), 8, p.012010_1 - 012010_6, 2015/09
The J-PARC 3-50BT line is the beam transport line from 3-GeV rapid-cycling synchrotron (RCS) to 50-GeV main ring (MR). The RCS is the high-intensity proton accelerator, where designed beam power is 1 MW, and has the complex source of space charge effect, etc. Therefore, the uncontrolled emittance growth and beam halo increase nonlinearly with the increasing the beam power. Additionally, the physical aperture of MR with 81 
mm mrad is smaller than that of RCS with 486 mm mrad. Therefore, the 3-50BT line has the collimators in order to remove the tail or halo of the extracted beam from the RCS. The designed collimator aperture is 54 mm mrad. It is required to measure and optimize the optics parameters in the collimator area for taking full advantage of the beam collimation. Especially, it is very important to make the dispersion functions free in the collimator area and optimize the beta function. This paper will introduce the method of optics measurement and report the result of the measurement and optimization based on the simulation.
Ajimura, Shuhei*; Bezerra, T. J. C.*; Chauveau, E.*; Enomoto, T.*; Furuta, Hisataka*; Harada, Masahide; Hasegawa, Shoichi; Hiraiwa, T.*; Igarashi, Yoichi*; Iwai, Eito*; et al.
Progress of Theoretical and Experimental Physics (Internet), 2015(6), p.063C01_1 - 063C01_19, 2015/06
Times Cited Count：6 Percentile：45.25(Physics, Multidisciplinary)The J-PARC E56 experiment aims to search for sterile neutrinos at the J-PARC Materials and Life Science Experimental Facility (MLF). In order to examine the feasibility of the experiment, we measured the background rates of different detector candidate sites, which are located at the third floor of the MLF, using a detector consisting of plastic scintillators with a fiducial mass of 500 kg. The gammas and neutrons induced by the beam as well as the backgrounds from the cosmic rays were measured, and the results are described in this article.
Harada, Hiroyuki; Meigo, Shinichiro; Shirakata, Masashi*; Sato, Yoichi*; Tamura, Fumihiko; Tejima, Masaki*; Hashimoto, Yoshinori*; Igarashi, Susumu*; Koseki, Tadashi
Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.39 - 43, 2014/06
The J-PARC 3-50 BT line is the beam transport line of extracted beam from 3-GeV rapid-cycling synchrotron (RCS) to 50-GeV main ring (MR). The RCS is the high-intensity proton accelerator, which designed beam power is 1 MW, and has the complex source of space charge effect, etc. Therefore, the uncontrolled emittance growth and beam halo increase nonlinearly with the increasing the beam power. Additionally, physical aperture of MR with 81 mm mrad is smaller than that of RCS with 486 mm mrad. Therefore, the 3-50 BT line has the collimators in order to scrape the tail/halo of extracted beam from the RCS. The designed collimator aperture is 54 mm mrad. It is required to measure and optimize the optics parameter in the collimator area for taking full advantage of beam collimation. This paper will introduce the method of optics measurement and report the result of the measurement and optimization based on the simulation.
and 
Horiguchi, Akane*; Ariga, Hirotake*; Igarashi, Junko*; Katori, Taku*; Sakata, Yoichi*; Hayashi, Takahisa*; Taji, Teruaki*; Yoshihara, Ryohei; Nozawa, Shigeki; Hase, Yoshihiro; et al.
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no abstracts in English
