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Harada, Hiroyuki; Saha, P. K.; Kinsho, Michikazu
JPS Conference Proceedings (Internet), 33, p.011028_1 - 011028_6, 2021/03
Recently, humankind had big discovery about neutron star, which is great big nuclear in the space. They are discovery of neutron star with twice mass of solar in 2010 and detection of gravity wave when two neutron stars incorporate in 2017. In order to understand the high dense matter like the neutron star, project of experimental researches by using accelerated heavy ion beams are planed in the world. The J-PARC facility consists of three accelerators, which are 400 MeV linac, 3 GeV rapid cycling synchrotron and Main Ring synchrotron. The accelerated MW class high intensity proton beams are used in many experiments. We have simulation study of the heavy ion beam in J-PARC to fully utilize high intensity ability of J-PARC. We propose the accelerator scheme of the beam in J-PARC and the intensity will reach to the world record. In my talk, I will introduce the accelerator scheme for the high-intensity heavy ion beam in J-PARC.
Yoshimoto, Masahiro; Nakanoya, Takamitsu; Yamazaki, Yoshio; Saha, P. K.; Kinsho, Michikazu; Yamamoto, Shunya*; Okazaki, Hiroyuki*; Taguchi, Tomitsugu*; Yamada, Naoto*; Yamagata, Ryohei*
JPS Conference Proceedings (Internet), 33, p.011019_1 - 011019_7, 2021/03
The multi-turn charge-exchange H
beam injection scheme with stripper foils is one of the key techniques to achieve a MW-class high power proton beam. The J-PARC RCS adopts Hybrid type Boron-doped Carbon (HBC) stripper foil, which was developed in KEK to improve the lifetime. Indeed, the RCS user operation confirmed that HBC foil has the great advantage of a longer lifetime against high beam irradiation. To examine characteristics of the HBC foils, various beam studies were performed, such as the stripping efficiency measurement and long-term observation with an H beam in the J-PARC RCS, foil analysis using RBS, EDR and PIXE methods, and SEM and TEM observation after the ion beam irradiation in Takasaki Ion Accelerators for Advanced Radiation Application (TIARA) on National Institutes for Quantum and Radiological Science and Technology (QST). Recently, the deposition apparatus for the HBC foils from the KEK Tsukuba-site was relocated to the JAEA Tokai-site, and we started fabrication of new HBC foil in 2017. (The new one fabricated in JAEA we call J-HBC foil.) And, we continue investigations in TIARA with the J-HBC foils. Furthermore, in-depth researches by changing the process parameters of the foil deposition are carried on. Recent results suggest that the amount of the boron doped in the foil is more important parameter than the ratio of the discharge amount of carbon from cathode and anode electrodes. In this presentation, we will report the details of recent analysis of the J-HBC foil.
Nakashima, Hiroshi
JAEA-Conf 2020-001, p.69 - 74, 2020/12
J-PARC (Japan Proton Accelerator Research Complex) is a high-energy proton accelerator complex of the world's highest beam power. Because of its very high beam power and its high energy as well as the large-scale accelerator complex, we encountered some very difficult problems on radiation safety design. Various examinations and countermeasures were considered in order to overcome the difficulty. This paper introduces some of them. In addition, some new knowledge obtained during 10 years after completion are described.
Hotchi, Hideaki
FAS Dayori (Internet), (18), p.20 - 26, 2019/06
no abstracts in English
Okabe, Kota; Yamamoto, Kazami; Kamiya, Junichiro; Takayanagi, Tomohiro; Yamamoto, Masanobu; Yoshimoto, Masahiro; Takeda, Osamu*; Horino, Koki*; Ueno, Tomoaki*; Yanagibashi, Toru*; et al.
Proceedings of 14th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.853 - 857, 2017/12
The most important issue is to reduce the uncontrolled beam loss in the high intensity hadron accelerator such as J-PARC proton accelerators. The J-PARC 3 GeV Synchrotron (RCS) has a collimator system which narrows a high intensity beam in the RCS. After startup of RCS in 2007, the collimator system of the RCS worked well. However, in April 2016, vacuum leakage at the collimator system occurred during the maintenance operation. To investigate a cause of the failure, we took apart iron shields of the collimator reducing exposed dose of operators. As a result of inspection, we succeeded to identify the cause of the vacuum leakage failure. In this presentation, we report the failure investigation of the beam collimator system in the RCS.
Hotchi, Hideaki; Harada, Hiroyuki; Kato, Shinichi; Okabe, Kota; Saha, P. K.; Shobuda, Yoshihiro; Tamura, Fumihiko; Tani, Norio; Watanabe, Yasuhiro; Yoshimoto, Masahiro
Proceedings of 8th International Particle Accelerator Conference (IPAC '17) (Internet), p.2470 - 2473, 2017/06
For this past year, RCS beam tuning was focused on realizing a high-intensity low-emittance beam required from the downstream facility. The extraction beam emittance including its tail part was successfully decreased by optimizing transverse injection painting, and tune and chromaticity manipulations, where bipolar sextupole field patterns were newly introduced to simultaneously achieve emittance growth mitigation at the early stage of acceleration and beam instability suppression after the middle stage of acceleration. This paper presents the recent experimental results, together with detailed discussions for the emittance growth and its mitigation mechanisms.
Hotchi, Hideaki
Proceedings of 54th ICFA Advanced Beam Dynamics Workshop on High-Intensity, High Brightness and High Power Hadron Beams (HB 2014) (Internet), p.6 - 11, 2015/03
The J-PARC 3-GeV Rapid Cycling Synchrotron (RCS) is the world's highest class of high-power pulsed proton driver aiming at 1-MW output beam power. In the last summer shutdown of 2013, the injection energy from the linac was upgraded from 181 MeV to the design value of 400 MeV. In addition, in this summer shutdown of 2014, the maximum peak current of the injection beam was increased from 30 mA to the design value of 50 mA. In October 2014 after completing these series of the injector linac upgrades, we have started the final stage of beam tuning toward the design output beam power of 1 MW. The most important issues in realizing such a high power 1 MW beam operation are control and minimization of beam loss. This talk will present our approaches to beam loss issues that we faced on the process of the beam power ramp-up.
Hasegawa, Kazuo
Proceedings of 2005 Particle Accelerator Conference (PAC '05) (CD-ROM), p.220 - 224, 2005/00
no abstracts in English
Hasegawa, Kazuo
Proceedings of 34th ICFA Advanced Beam Dynamics Workshop on High Power Superconducting Ion, Proton and Multi-Species Linacs (HPSL 2005) (Internet), 7 Pages, 2005/00
no abstracts in English
Okabe, Kota
no journal, ,
In the Japan Proton Accelerator Research Complex (J-PARC) 3-GeV rapid cycle synchrotron (RCS), supression of the transverse beam halo for the injected beam int the RCS is required to increase the output beam power. Transverse beam matching of the injection beam at the Linac-RCS beam transport line (L3BT) is one of the most useful method to reduce a beam loss in the RCS. Results of the beam commissioning for high intensity operation at the RCS, beam loss in the RCS and halo compornent of the extracted beam from the RCS ware supressed by the transverce matching methd. In this presentation, we will report the injection beam matching method at the L3BT and discuss the space charge phenomena about the high intensity beam.
Yoshimoto, Masahiro; Nakanoya, Takamitsu; Yamazaki, Yoshio; Saha, P. K.; Kinsho, Michikazu; Yamamoto, Shunya*; Okazaki, Hiroyuki*; Taguchi, Tomitsugu*; Yamada, Naoto*; Yamagata, Ryohei*
no journal, ,
The multi-turn charge-exchange H beam injection scheme with stripper foils is one of the key techniques to achieve a MW-class high power proton beam. The J-PARC RCS adopts Hybrid type Boron-doped Carbon (HBC) stripper foil, which was developed in KEK to improve the lifetime. Indeed, the RCS user operation confirmed that HBC foil has the great advantage of a longer lifetime against high beam irradiation. To examine characteristics of the HBC foils, various beam studies were performed, such as the stripping efficiency measurement and long-term observation with an H beam in the J-PARC RCS, foil analysis using RBS, EDR and PIXE methods, and SEM and TEM observation after the ion beam irradiation in Takasaki Ion Accelerators for Advanced Radiation Application (TIARA) on National Institutes for Quantum and Radiological Science and Technology (QST). Recently, the deposition apparatus for the HBC foils from the KEK Tsukuba-site was relocated to the JAEA Tokai-site, and we started fabrication of new HBC foil in 2017. (The new one fabricated in JAEA we call J-HBC foil.) And, we continue investigations in TIARA with the J-HBC foils. Furthermore, in-depth researches by changing the process parameters of the foil deposition are carried on. Now, we developed new types of foils which were made by arc discharge method by using a pure carbon rod for ether the anode electrode or the cathode electrode. As the results of the beam irradiation tests for the new types of HBC foils, it was suggested that the boron being carried in from the anode electrode plays an important part in the functioning of the stripper foil. The new knowledge will mark a milestone in the improvement of the stripper foil.
Fuwa, Yasuhiro; Moriya, Katsuhiro; Takayanagi, Tomohiro
no journal, ,
In the high-intensity operation of the J-PARC Linac, it is necessary to suppress the beam loss caused by the emittance growth and the beam halo formation due to the space charge in the low-energy region. As a method to suppress the space charge effect, it has been proposed to cancel the effect of higher-order components of the space charge effect by using higher-order multipole fields such as octupole fields. In this presentation, we will report the characteristics of the multipole magnets fabricated for the MEBT1 of the J-PARC Linac and simulation results on the suppression of the space charge effect based on the magnetic field distribution generated by the fabricated magnet.
Kojima, Kunihiro*; Okamoto, Hiromi*; Moriya, Katsuhiro
no journal, ,
no abstracts in English
