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Journal Articles

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, 32 Pages, 2022/02

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.

Journal Articles

Combined effect of flux pinning by three-directional columnar defects in a field-angular region of high-$$T_{rm c}$$ superconductors

Sueyoshi, Tetsuro*; Enokihata, Ryusei*; Hidaka, Yuka*; Irie, Masahiro*; Fujiyoshi, Takanori*; Okuno, Yasuki*; Ishikawa, Norito

Physica C, 582, p.1353824_1 - 1353824_5, 2021/03

We investigated the combined effect of flux pinning by three-directional columnar defects (CDs) in a wide field-angular range of YBa$$_{2}$$Cu$$_{3}$$Oy thin films, where CDs parallel to the $$c$$-axis and CDs crossing at $$pm$$$$theta$$ ($$theta$$=45$$^{circ}$$, 60$$^{circ}$$ and 80$$^{circ}$$) relative to the c-axis were installed by 200 MeV Xe-ion irradiations. The three-directional CDs with $$theta$$$$leqq$$$$pm$$60$$^{circ}$$ form a field angular curve of critical current density Jc with a broad peak centered at magnetic field (B) parallel to the $$c$$-axis, whereas the Jc shows no peaks around the crossing angles of $$pm$$$$theta$$. When the crossing angle is expanded to $$theta$$=$$pm$$80$$^{circ}$$, a drastic change in the field- angular behavior of Jc is induced: there is not a large enhancement of $$J_{rm c}$$ around B//c. We also demonstrated that the combined configuration consisting of CDs at $$theta$$= 0$$^{circ}$$, $$pm$$45$$^{circ}$$, $$pm$$60$$^{circ}$$ and $$pm$$80$$^{circ}$$ provides a uniform enhancement of $$J_{rm c}$$ over a wide angular-region.

Journal Articles

First measurement and online monitoring of the stripper foil thinning and pinhole formation to achieve a longer foil lifetime in high-intensity accelerators

Saha, P. K.; Yoshimoto, Masahiro; Hatakeyama, Shuichiro; Hotchi, Hideaki; Harada, Hiroyuki; Tamura, Fumihiko; Yamamoto, Kazami; Yamazaki, Yoshio; Kinsho, Michikazu; Irie, Yoshiro*

Physical Review Accelerators and Beams (Internet), 23(8), p.082801_1 - 082801_13, 2020/08

 Times Cited Count:1 Percentile:35.83(Physics, Nuclear)

Journal Articles

A Fluorometric skin-interfaced microfluidic device and smartphone imaging module for ${{it in situ}}$ quantitative analysis of sweat chemistry

Sekine, Yurina; Kim, S. B.*; Zhang, Y.*; Bandodkar, A. J.*; Xu, S.*; Choi, J.*; Irie, Masahiro*; Ray, T. R.*; Kohli, P.*; Kozai, Naofumi; et al.

Lab on a Chip, 18(15), p.2178 - 2186, 2018/08

The rich composition of solutes and metabolites in sweat and its relative ease of collection upon excretion from skin pores make this class of biofluid an attractive candidate for point of care analysis. Here, we present a complementary approach that exploits fluorometric sensing modalities integrated into a soft, skin-interfaced microfluidic system which, when paired with a simple smartphone-based imaging module, allows for in-situ measurement of important biomarkers in sweat. A network array of microchannels and a collection of microreservoirs pre-filled with fluorescent probes that selectively react with target analytes in sweat (e.g. probes), enable quantitative, rapid analysis. Field studies on human subjects demonstrate the ability to measure the concentrations of chloride, sodium and zinc in sweat, with accuracy that matches that of conventional laboratory techniques.

Journal Articles

Progress status of proof-of-principle demonstration of 400 MeV H$$^{-}$$ laser stripping at J-PARC 3-GeV RCS

Saha, P. K.; Harada, Hiroyuki; Kinsho, Michikazu; Miura, Akihiko; Yoshimoto, Masahiro; Okabe, Kota; Suganuma, Kazuaki; Yamane, Isao*; Irie, Yoshiro*; Liu, Y.*; et al.

Proceedings of 15th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.806 - 810, 2018/08

Journal Articles

Status of proof-of-principle demonstration of 400 MeV H- stripping to proton by using only lasers at J-PARC

Saha, P. K.; Harada, Hiroyuki; Kinsho, Michikazu; Miura, Akihiko; Yoshimoto, Masahiro; Irie, Yoshiro*; Yamane, Isao*; Yoneda, Hitoki*; Michine, Yurina*

Proceedings of 61st ICFA Advanced Beam Dynamics Workshop on High-Intensity and High-Brightness Hadron Beams (HB 2018) (Internet), p.422 - 427, 2018/07

Journal Articles

Status of proof-of-principle experiment for 400 MeV H$$^{-}$$ stripping to protons by using only lasers in the 3-GeV RCS of J-PARC

Saha, P. K.; Harada, Hiroyuki; Yamane, Isao*; Kinsho, Michikazu; Miura, Akihiko; Okabe, Kota; Liu, Y.*; Yoshimoto, Masahiro; Kato, Shinichi; Irie, Yoshiro*

Proceedings of 14th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.866 - 870, 2017/12

Journal Articles

Measurement of continuous degradation of a stripper foil during ths operation with 300 kW beam power in the 3-GeV RCS of J-PARC

Saha, P. K.; Yoshimoto, Masahiro; Hotchi, Hideaki; Harada, Hiroyuki; Okabe, Kota; Yamazaki, Yoshio; Kinsho, Michikazu; Irie, Yoshiro*

Journal of Radioanalytical and Nuclear Chemistry, 305(3), p.851 - 857, 2015/09

 Times Cited Count:1 Percentile:12.03(Chemistry, Analytical)

Journal Articles

Maintenance of radio-activated stripper foils in the 3 GeV RCS of J-PARC

Yoshimoto, Masahiro; Yamazaki, Yoshio; Saha, P. K.; Kinsho, Michikazu; Sugai, Isao*; Irie, Yoshiro*

Journal of Radioanalytical and Nuclear Chemistry, 305(3), p.865 - 873, 2015/09

 Times Cited Count:0 Percentile:0.01(Chemistry, Analytical)

In the 3-GeV Rapid Cycling Synchrotron (RCS) of the Japan Proton Accelerator Research Complex (J-PARC), we adopted thick Hybrid type Boron-doped Carbon (HBC) stripper foil for the multi-turn H$$^{-}$$ charge-exchange injection. The HBC foil has a great advantage of its longer lifetime against high irradiation. Until now, deformation of the HBC foil is observed, but has not broken during 6 months user operation. However there are high residual dose in the RCS injection area. The highest residual dose is observed at the downstream of titanium chamber flange where the stripper foil is placed. The residual dose was increased with the LINAC energy upgrade from 181 MeV to 400 MeV. It shows that secondary neutrons and protons generated by nuclear reactions in the stripper foil at high energy and high power beam irradiation are the major sources for high residual dose at the injection area. The radio-activation of the stripper foil itself is an intrinsic problem and thus maintenance scenario of the stripper foil at the highly-dosed environment is one of the most important issues for the high intensity accelerators. In the J-PARC RCS, the foil exchange devices were improved according to the new maintenance scenario which aims to keep radiation exposure to staffs as low as possible and to reduce the risk of the radioactive foils break up or disperse. In addition, various analyses of the irradiated stripper foils can be carried out if the foils can be retrieved from the tunnel without breaking.

Journal Articles

Preliminary studies of laser-assisted H$$^{-}$$ stripping at 400 MeV

Saha, P. K.; Harada, Hiroyuki; Kinsho, Michikazu; Maruta, Tomofumi*; Okabe, Kota; Yoshimoto, Masahiro; Irie, Yoshiro*; Gorlov, T.*

Proceedings of 6th International Particle Accelerator Conference (IPAC '15) (Internet), p.3795 - 3797, 2015/06

Journal Articles

Measurement of 181 MeV H$$^{-}$$ ions stripping cross-sections by carbon stripper foil

Saha, P. K.; Yoshimoto, Masahiro; Yamazaki, Yoshio; Hotchi, Hideaki; Harada, Hiroyuki; Okabe, Kota; Kinsho, Michikazu; Irie, Yoshiro*

Nuclear Instruments and Methods in Physics Research A, 776, p.87 - 93, 2015/03

 Times Cited Count:6 Percentile:54.79(Instruments & Instrumentation)

Journal Articles

Progress of injection energy upgrade project for J-PARC RCS

Hayashi, Naoki; Harada, Hiroyuki; Horino, Koki; Hotchi, Hideaki; Kamiya, Junichiro; Kinsho, Michikazu; Saha, P. K.; Shobuda, Yoshihiro; Takayanagi, Tomohiro; Tani, Norio; et al.

Proceedings of 4th International Particle Accelerator Conference (IPAC '13) (Internet), p.3833 - 3835, 2014/07

no abstracts in English

Journal Articles

High intensity beam trial of up to 540 kW in J-PARC RCS

Hotchi, Hideaki; Harada, Hiroyuki; Hayashi, Naoki; Kinsho, Michikazu; Saha, P. K.; Shobuda, Yoshihiro; Tamura, Fumihiko; Yamamoto, Kazami; Yamamoto, Masanobu; Yoshimoto, Masahiro; et al.

Proceedings of 4th International Particle Accelerator Conference (IPAC '13) (Internet), p.3836 - 3838, 2014/07

In November 2012, we have performed a high intensity beam trial of up to 540 kW. The beam loss for 540 kW intensity beam was well reduced from 30% to 2% by injection painting. This remaining beam loss of 2%, arising from foil scattering and 100-kHz field ripple induced by injection bump field, corresponds to 650 W in power, which is still less than 1/6 of the current collimator capability of 4 kW. The numerical simulation well reproduced the experimental results. Accelerator modelling and quantitative benchmarking between experiment and numerical simulation becomes feasible. The numerical simulation very much helped us to understand the mechanism of observed beam loss. Also several beam loss mitigation ideas were proposed with a help of numerical simulation and verified by experiment.

Journal Articles

Quantitative monitoring of the stripper foil degradation in the 3-GeV rapid cycling synchrotron of the Japan proton accelerator research complex

Saha, P. K.; Yoshimoto, Masahiro; Yamazaki, Yoshio; Hotchi, Hideaki; Harada, Hiroyuki; Hayashi, Naoki; Yamamoto, Kazami; Kinsho, Michikazu; Irie, Yoshiro*

Journal of Radioanalytical and Nuclear Chemistry, 299(2), p.1041 - 1046, 2014/02

 Times Cited Count:3 Percentile:28.59(Chemistry, Analytical)

Journal Articles

HBC foil beam study and long-term observation at the 3-GeV RCS in J-PARC

Yoshimoto, Masahiro; Saha, P. K.; Yamazaki, Yoshio; Kawase, Masato; Saeki, Riuji; Hayashi, Naoki; Yamamoto, Kazami; Hotchi, Hideaki; Ishiyama, Tatsuya; Kinsho, Michikazu; et al.

Journal of Physics; Conference Series, 417, p.012073_1 - 012073_6, 2013/03

 Times Cited Count:4 Percentile:79.92

The HBC foil are installed in the J-PARC RCS for the charge-exchange H$$^{-}$$ beam injection. In order to examine the characteristics of the HBC foils, beam studies for the HBC foil were carried out from the viewpoint of foil's life time and the beam survival rate due to foils. According to the compromise between charge-exchange efficiency and foil scattering beam loss, we optimized the foils thickness for user operation. The long-term observation during the user operation as well as the HBC foil endurance test for its life time evaluation was carried out. Even after one year was operation, there was no deterioration of the stripping foil.

Journal Articles

The Result of beam commissioning in J-PARC 3-GeV RCS

Harada, Hiroyuki; Hotchi, Hideaki; Saha, P. K.; Shobuda, Yoshihiro; Hayashi, Naoki; Yamamoto, Kazami; Yoshimoto, Masahiro; Tamura, Fumihiko; Yamamoto, Masanobu; Kinsho, Michikazu; et al.

Proceedings of 52nd ICFA Advanced Beam Dynamics Workshop on High-Intensity and High-Brightness Hadron Beams (HB 2012) (Internet), p.339 - 343, 2012/09

J-PARC 3-GeV RCS has started the beam commissioning since Oct. 2007. In the beam commissioning, the beam tuning for basic parameters and high-intensity operation has been continuously performed. This presentation will describe the results of the beam-loss reduction and minimization for high-intensity operation.

Journal Articles

Beam halo reduction in the J-PARC 3-GeV RCS

Hotchi, Hideaki; Harada, Hiroyuki; Saha, P. K.; Shobuda, Yoshihiro; Tamura, Fumihiko; Yamamoto, Kazami; Yamamoto, Masanobu; Yoshimoto, Masahiro; Irie, Yoshiro*; Koseki, Tadashi*; et al.

Proceedings of 3rd International Particle Accelerator Conference (IPAC '12) (Internet), p.3918 - 3920, 2012/05

The RCS beam power ramp-up has well proceeded since the start-up of user program in December 2008. So far the RCS has successfully achieved high intensity beam trials up to 420 kW at a low-level intensity loss of less than 1%, and the output beam power for the routine user program has been increased to 210 kW to date. Recently our effort has also been made to improve the quality of the extraction beam, namely to realize low-halo high-power beams. In this paper, recent effort for beam halo reduction in the RCS will be presented.

Journal Articles

Beam loss reduction by injection painting in the 3-GeV rapid cycling synchrotron of the Japan Proton Accelerator Research Complex

Hotchi, Hideaki; Harada, Hiroyuki; Hayashi, Naoki; Kinsho, Michikazu; Saha, P. K.; Shobuda, Yoshihiro; Tamura, Fumihiko; Yamamoto, Kazami; Yamamoto, Masanobu; Yoshimoto, Masahiro; et al.

Physical Review Special Topics; Accelerators and Beams, 15(4), p.040402_1 - 040402_15, 2012/04

 Times Cited Count:23 Percentile:78.47(Physics, Nuclear)

The J-PARC 3-GeV RCS was commissioned in October 2007. Via the initial beam tuning and a series of underlying beam studies with low-intensity beams, since December 2009, we have intermittently been performing beam tuning experiments with higher-intensity beams including the injection painting technique. By optimizing the injection painting parameters, we have successfully achieved a 420 kW-equivalent output intensity at a low-level intensity loss of less than 1%. In this paper, we present the experimental results obtained in the course of the RCS beam power ramp-up, especially on the beam loss reduction achieved by employing the injection painting.

Journal Articles

Beam commissioning and operation of the Japan Proton Accelerator Research Complex 3-GeV rapid cycling synchrotron

Hotchi, Hideaki; Harada, Hiroyuki; Hayashi, Naoki; Kinsho, Michikazu; Saha, P. K.; Shobuda, Yoshihiro; Tamura, Fumihiko; Yamamoto, Kazami; Yamamoto, Masanobu; Yoshimoto, Masahiro; et al.

Progress of Theoretical and Experimental Physics (Internet), 2012(1), p.02B003_1 - 02B003_26, 2012/00

 Times Cited Count:13 Percentile:64.55(Physics, Multidisciplinary)

The J-PARC 3-GeV RCS is a high-power pulsed proton driver aiming at 1 MW output beam power. The RCS was beam commissioned in October 2007 and made available for user operation in December 2008 with an output beam power of 4 kW. Since then, the output beam power of the RCS has been steadily increasing as per progressions of beam tuning and hardware improvements. So far, the RCS has successfully achieved high-intensity beam trials of up to 420 kW at a low-level intensity loss of less than 1%, and the output beam power for the routine user program has been increased to 210 kW. The most important issues in increasing the output beam power are the control and minimization of beam loss to maintain machine activation within the permissible level. This paper presents the recent progress in the RCS beam power ramp-up scenario, with particular emphasis on our efforts for beam loss issues.

Journal Articles

Measurement of the stripping efficiency for HBC stripper foil in the 3-GeV RCS of J-PARC

Saha, P. K.; Yoshimoto, Masahiro; Hatakeyama, Shuichiro; Hotchi, Hideaki; Harada, Hiroyuki; Yamazaki, Yoshio; Kinsho, Michikazu; Irie, Yoshiro*; Sugai, Isao*

Proceedings of 2nd International Particle Accelerator Conference (IPAC 2011) (Internet), p.3511 - 3513, 2011/09

35 (Records 1-20 displayed on this page)