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Journal Articles

Simulation study of heavy ion acceleration in J-PARC

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.

Journal Articles

Development of laser system for laser stripping injection

Harada, Hiroyuki; Saha, P. K.; Yoneda, Hitoki*; Michine, Yurina*; Fuchi, Aoi*; Sato, Atsushi*; Kinsho, Michikazu

JPS Conference Proceedings (Internet), 33, p.011026_1 - 011026_6, 2021/03

The charge-exchange multi-turn injection by using a carbon stripper foil is adopted in high-intensity proton ring accelerators worldwide. It is a beneficial method to compress the pulsed proton beam with high intensity but there are serious issues for high intensity. First issue is a short lifetime of the foil by deformation or breaking itself. Another issue is high radiation dose corresponding to the scattered particles on the foil. Therefore, a non-destructive stripping injection method is required for higher intensity proton beam. We newly propose a non-destructive method of H$$^{-}$$ stripping by using only laser. The new method is called "laser stripping injection". To establish our method, we are preparing for a POP (Proof-of-Principle) experiment of 400 MeV H- stripping to proton at J-PARC. In our presentation we will present the current status of laser system development for laser stripping injection at J-PARC.

Journal Articles

New method for high resolution analysis of betatron tune in a rapid cycling synchrotron or a booster ring

Harada, Hiroyuki; Hayashi, Naoki

JPS Conference Proceedings (Internet), 33, p.011027_1 - 011027_6, 2021/03

The transverse betatron tune is one of the most important key parameters in a ring accelerator because emittance growth and beam loss occur directly in case of crossing a betatron resonance. Especially, the tune must be required a controll with high accuracy in high intensity proton accelerator from the view point of space charge force and the beam instability. In general measurement method, the betatron tune is measured by analyzing the detected beam oscillation on Fourier transform. However, the beam is quickly accelerated and the revolution frequency of the beam changes quickly in a rapid cycling synchrotron. So, the tune accuracy is not improved. A new method was developed for high resolution analysis of the tune and was evaluated in J-PARC accelerator. Tune accuracy was successfully improved from 0.013 to less than 0.001. Tune controll with high accuracy is base for high-intensity beam. In this paper, the new method is introduced and the measured result in J-PARC is report.

Journal Articles

1.2-MW-equivalent high-intensity beam tests in J-PARC RCS

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

JPS Conference Proceedings (Internet), 33, p.011018_1 - 011018_6, 2021/03

no abstracts in English

Journal Articles

Flexible chopper gate pulse generation for the J-PARC RCS

Tamura, Fumihiko; Yamamoto, Masanobu; Yoshii, Masahito*; Sugiyama, Yasuyuki*; Hotchi, Hideaki; Saha, P. K.; Yoshimoto, Masahiro; Harada, Hiroyuki

JPS Conference Proceedings (Internet), 33, p.011021_1 - 011021_6, 2021/03

Chopped beam injection is employed in the J-PARC RCS to avoid the longitudinal beam losses. A fast beam chopper is installed in the MEBT section of the linac. The chopper is driven by the gate pulses sent from the LLRF control system of the RCS. The delay from the zero crossing of the RCS rf and the width are set so that the beam pulse is injected into the proper phase position of the rf bucket. A unique feature of the J-PARC chopper gate pulse generation is thinning of the pulses. The thinning is useful to control the beam intensity without changing much the condition of the longitudinal painting. Also, the beam macro pulse can be trimmed down to a single intermediate pulse by setting the parameters. In this poster, we present the overview of the generation of the chopper gate pulse in the LLRF control system and various beam commissioning results utilizing the flexibility of it. Also, we discuss the upgrade of the chopper gate pulse generation.

Journal Articles

Studies of laser power reduction for the laser stripping of 400 MeV $$H^{-}$$ beam at J-PARC RCS

Saha, P. K.; Harada, Hiroyuki; Kinsho, Michikazu; Yoneda, Hitoki*; Michine, Yurina*; Fuchi, Aoi*; Sato, Atsushi*; Liu, Y.*

JPS Conference Proceedings (Internet), 33, p.011025_1 - 011025_7, 2021/03

Journal Articles

High-spin states in $$^{35}$$S

Go, Shintaro*; Ideguchi, Eiji*; Yokoyama, Rin*; Aoi, Nori*; Azaiez, F.*; Furutaka, Kazuyoshi; Hatsukawa, Yuichi; Kimura, Atsushi; Kisamori, Keiichi*; Kobayashi, Motoki*; et al.

Physical Review C, 103(3), p.034327_1 - 034327_8, 2021/03

 Times Cited Count:0 Percentile:0.03(Physics, Nuclear)

Journal Articles

Water distribution in Nafion thin films on hydrophilic and hydrophobic carbon substrates

Ito, Kanae; Harada, Masashi*; Yamada, Norifumi*; Kudo, Kenji*; Aoki, Hiroyuki; Kanaya, Toshiji*

Langmuir, 36(43), p.12830 - 12837, 2020/11

 Times Cited Count:2 Percentile:21.55(Chemistry, Multidisciplinary)

JAEA Reports

Decommissioning of the Uranium Enrichment Laboratory

Kokusen, Junya; Akasaka, Shingo*; Shimizu, Osamu; Kanazawa, Hiroyuki; Honda, Junichi; Harada, Katsuya; Okamoto, Hisato

JAEA-Technology 2020-011, 70 Pages, 2020/10

JAEA-Technology-2020-011.pdf:3.37MB

The Uranium Enrichment Laboratory in the Japan Atomic Energy Agency (JAEA) was constructed in 1972 for the purpose of uranium enrichment research. The smoke emitting accident on 1989 and the fire accident on 1997 had been happened in this facility. The research on uranium enrichment was completed in JFY1998. The decommissioning work was started including the transfer of the nuclear fuel material to the other facility in JFY2012. The decommissioning work was completed in JFY2019 which are consisting of removing the hood, dismantlement of wall and ceiling with contamination caused by fire accident. The releasing the controlled area was performed after the confirmation of any contamination is not remained in the target area. The radioactive waste was generated while decommissioning, burnable and non-flammable are 1.7t and 69.5t respectively. The Laboratory will be used as a general facility for cold experiments.

Journal Articles

Status of laser development for laser stripping experiment at J-PARC

Harada, Hiroyuki; Saha, P. K.; Yoneda, Hitoki*; Michine, Yurina*; Fuchi, Aoi*; Sato, Atsushi*; Shibata, Takanori*; Kinsho, Michikazu

Proceedings of 17th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.441 - 445, 2020/09

The high-intensity proton accelerator adopts a charge exchange injection scheme, which injects with exchanging from negative Hydrogen ion to proton by using carbon foil. This scheme is destructive-type method by using the foil and can accumulate high intensity proton beam. However, the uncontrolled beam losses by scattering at the foil and the foil breaking by the beam collision are a key issue of high-intensity proton accelerator. In order to realize higher intensity, new injection scheme of non-destructive type is needed instead of the foil. We newly propose laser stripping injection scheme by using laser pulse. We plan proof of principle experiment at J-PARC and are developing the laser system. In my presentation, we introduce the overview of laser stripping injection scheme and report the status of laser development.

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

J-PARC 3-GeV RCS; 1-MW beam operation and beyond

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

Journal of Instrumentation (Internet), 15(7), p.P07022_1 - P07022_16, 2020/07

 Times Cited Count:1 Percentile:27.17(Instruments & Instrumentation)

no abstracts in English

Journal Articles

J-PARC RCS; High-order field components inherent in the injection bump magnets and their effects on the circulating beam during multi-turn injection

Hotchi, Hideaki; Harada, Hiroyuki; Takayanagi, Tomohiro

Journal of Physics; Conference Series, 1350, p.012102_1 - 012102_5, 2019/11

 Times Cited Count:1 Percentile:65.18

Journal Articles

Energy measurement and correction for stable operation in J-PARC

Moriya, Katsuhiro; Harada, Hiroyuki; Liu, Y.*; Otani, Masashi*

Journal of Physics; Conference Series, 1350, p.012140_1 - 012140_5, 2019/11

 Times Cited Count:0 Percentile:0.07

Journal Articles

1st Workshop against proposal by Young Researchers Association of the Japan Beam Physics Club "Discussing and Brainstorming for the World of Beam Physics in the thirty years ahead"

Sakaue, Kazuyuki*; Harada, Hiroyuki

Kasokuki, 16(3), p.204 - 206, 2019/10

Beam is used for research base of wide disciplines and contributes to science technology, and is supported by beam physics. Young Researchers Association of the Japan Beam Physics Club was established to lead to contribution for science technology by communication among young researchers at April 2018. Our club was newly established the workshop against proposal and the 1st workshop of "Discussing and Brainstorming for the World of Beam Physics in the thirty years ahead" was holed at Kyoto on July 30th 2019. This paper will report the 1st workshop.

Journal Articles

Beam dynamics study for beam loss mitigation in the J-PARC RCS

Hotchi, Hideaki; Harada, Hiroyuki; Okabe, Kota; Saha, P. K.; Shobuda, Yoshihiro; Tamura, Fumihiko; Yoshimoto, Masahiro

Kasokuki, 16(2), p.109 - 118, 2019/07

no abstracts in English

Journal Articles

Recent progress of the J-PARC RCS beam commissioning and operation; Efforts to realize a higher beam power beyond 1 MW

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

Proceedings of 16th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.574 - 578, 2019/07

no abstracts in English

Journal Articles

Development of two-mirror multi-pass laser system to reduce laser power for laser stripping injection at J-PARC 3-GeV RCS

Saha, P. K.; Harada, Hiroyuki; Kinsho, Michikazu; Sato, Atsushi*; Yoneda, Hitoki*; Michine, Yurina*

Proceedings of 16th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.841 - 845, 2019/07

Journal Articles

Study of heavy ion acceleration in J-PARC

Harada, Hiroyuki; Saha, P. K.; Kinsho, Michikazu

Proceedings of 16th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.179 - 182, 2019/07

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 observation of gravity wave when two neutron start 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 become heated in the world, such RHIC-BES-II program, FAIR project, NICA project, etc. The J-PARC provides MW class high intensity proton beams to many experiments and researches. We have 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 our talk, we will report the current status of proton beam and the accelerator scheme for the high-intensity heavy ion beam in J-PARC.

Journal Articles

Proposal of non-destructive device for slow extraction

Shimogawa, Tetsushi*; Harada, Hiroyuki

Proceedings of 16th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1156 - 1158, 2019/07

A particle beam from accelerators has been applied not only to physics experiments but also medical applications. In the slow extraction which extract beam from a synchrotron during a large number of turns, the accelerated beam is blown up and extracted by the electrostatic septum. The septum consists of electrode and septum for separating between extraction and circulating beam. Generally, the wire and plate are used for septum. In this case, the beam hits on septum. Consequently, the extraction efficiency and the beam power are limited. We propose the non-destructive electrostatic septum. The multiple electrodes arrange surround the beam and produce the electric field for separation and deflect the beam. There are no materials in the beam orbit area. This will be reported introduction of our proposed non-destructive electrostatic septum.

255 (Records 1-20 displayed on this page)