IPAC2017 - List of Authors (Yoshimoto, M.)

Paper	Title	Page
MOPAB070	Beam Position Measurement During Multi-Turn Painting Injection at the J-PARC RCS	277
	N. Hayashi, A. Miura, P.K. Saha, M. Yoshimoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	Multi-turn painting injection scheme is important for high intensity proton accelerators. At the J-PARC RCS, a transverse painting scheme was adapted by adding vertical painting magnets to the beam transport line before the injection point, with horizontal painting being performed by a set of dedicated pulse magnets in the ring. To establish a transverse painting condition, it is usual to base on the pulse magnet current pattern. However, it is more desirable to directly measure the beam orbit time variation for evaluation. A linac beam was chopped to match the ring RF bucket. We thought that it would be difficult to measure the position for each pulse; however, the average position could be extracted by introducing a particular device. For the beam injected into the ring, because the linac RF frequency component was diminished due to debunching quickly, one could determine its position in the beginning of the injection period. However, due to rebunching effect the position determination becomes difficult. This problem needs to be resolved.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB070
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MOPIK035	New Injection Scheme of J-PARC Rapid Cycling Synchrotron	579
	K. Yamamoto, H. Harada, H. Hotchi, J. Kamiya, P.K. Saha, T. Takayanagi, M. Yoshimoto JAEA/J-PARC, Tokai-mura, Japan N. Miki, O. Takeda Nippon Advanced Technology Co., Ltd., Tokai, Japan
	The 3-GeV Rapid Cycling Synchrotron (RCS) of Japan Proton Accelerator Research Complex (J-PARC) aims to deliver 1-MW proton beam to the neutron target and Main Ring synchrotron (MR). Present beam power of RCS is up to 500-kW and the higher radiation doses were concentrated in the injection area. These activations were caused by the interaction between the foil and the beam. To reduce the worker dose near the injection point, we have studied new design of the injection scheme to secure enough space for radiation shielding and bellows. In the new system, two of four injection pulse bump magnets are replaced and we are able to ensure the additional 500 mm space at the injection foil .
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK035
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TUPVA093	Radio-Activation Caused by Secondary Particles Due to Nuclear Reactions at the Stripper Foil in the J-PARC RCS	2300
	M. Yoshimoto, H. Hotchi, S. Kato, M. Kinsho, K. Okabe, K. Yamamoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	The most important issue in realizing such a MW-class high-power routine beam operation is to keep machine activations within a permissible level, that is, to preserve a better hands-on-maintenance environment. Thus, a large fraction of our effort has been concentrated on reducing and managing beam losses. However the high residual activation is appeared around the stripper foils. It is caused by not primary particles due to the beam losses but secondary particles due to nuclear reaction at the foil. This radio-activation is an intrinsically serious problem for the RCS which adopts the charge exchange multi-turn beam injection scheme with the stripper foil. In this presentation, we report a detail measurement of the residual dose around the stripper foil together with the cause estimated based on simulation studies.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA093
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TUPVA096	Detection of H⁰ Particles in MEBT2 Chicane of J-PARC Linac	2308
	J. Tamura, H. Ao, T. Maruta, A. Miura, T. Morishita, K. Okabe, M. Yoshimoto JAEA/J-PARC, Tokai-mura, Japan K. Futatsukawa, T. Miyao KEK, Ibaraki, Japan Y. Nemoto Nippon Advanced Technology Co., Ltd., Tokai, Japan
	In the Japan Proton Accelerator Research Complex (J-PARC), H⁰ particles generated by collisions of accelerated H⁻ beams with residual gases are considered as one of the key factors of the residual radiation in the high energy accelerating section of the linac. To diagnose the H⁰ particles, the new beam line for analyzing H⁰ and H⁻ particles was installed in the second medium energy beam transport (MEBT2), which is the matching section from the separated-type drift tube linac (SDTL) to the annular-ring coupled structure linac (ACS). The analysis line consists of four dipole magnets for giving the H⁻ beam chicane orbit, and a wire scanner monitor (WSM) for measuring the horizontal shift of the H⁻ beam. To detect the H⁰ particles, a carbon plate is installed to the WSM. In the beam commissioning, we detected the signals of H⁰ particles penetrating the plate and observed the transition of the signal with various vacuum condition in the SDTL section.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA096
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WEOAA3	Realizing a High-Intensity Low-Emittance Beam in the J-PARC 3-GeV RCS	2470
	H. Hotchi, H. Harada, S. Kato, K. Okabe, P.K. Saha, Y. Shobuda, F. Tamura, N. Tani, Y. Watanabe, M. Yoshimoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	The J-PARC 3-GeV rapid cycling synchrotron (RCS) has two functions; one as a proton driver to produce pulsed muons and neutrons, and the other as an injector to the following 50-GeV main ring (MR). RCS is now intensively developing a high-intensity beam test to realize a high-intensity low-emittance beam with less beam halo required from MR. This paper presents the recent experimental results, together with detailed discussions for the emittance growth and its mitigation mechanisms.
	Slides WEOAA3 [1.732 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEOAA3
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Paper

Title

Page

Beam Position Measurement During Multi-Turn Painting Injection at the J-PARC RCS

277

N. Hayashi, A. Miura, P.K. Saha, M. Yoshimoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

Multi-turn painting injection scheme is important for high intensity proton accelerators. At the J-PARC RCS, a transverse painting scheme was adapted by adding vertical painting magnets to the beam transport line before the injection point, with horizontal painting being performed by a set of dedicated pulse magnets in the ring. To establish a transverse painting condition, it is usual to base on the pulse magnet current pattern. However, it is more desirable to directly measure the beam orbit time variation for evaluation. A linac beam was chopped to match the ring RF bucket. We thought that it would be difficult to measure the position for each pulse; however, the average position could be extracted by introducing a particular device. For the beam injected into the ring, because the linac RF frequency component was diminished due to debunching quickly, one could determine its position in the beginning of the injection period. However, due to rebunching effect the position determination becomes difficult. This problem needs to be resolved.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB070

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPIK035

New Injection Scheme of J-PARC Rapid Cycling Synchrotron

579

K. Yamamoto, H. Harada, H. Hotchi, J. Kamiya, P.K. Saha, T. Takayanagi, M. Yoshimoto
JAEA/J-PARC, Tokai-mura, Japan
N. Miki, O. Takeda
Nippon Advanced Technology Co., Ltd., Tokai, Japan

The 3-GeV Rapid Cycling Synchrotron (RCS) of Japan Proton Accelerator Research Complex (J-PARC) aims to deliver 1-MW proton beam to the neutron target and Main Ring synchrotron (MR). Present beam power of RCS is up to 500-kW and the higher radiation doses were concentrated in the injection area. These activations were caused by the interaction between the foil and the beam. To reduce the worker dose near the injection point, we have studied new design of the injection scheme to secure enough space for radiation shielding and bellows. In the new system, two of four injection pulse bump magnets are replaced and we are able to ensure the additional 500 mm space at the injection foil .

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK035

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPVA093

Radio-Activation Caused by Secondary Particles Due to Nuclear Reactions at the Stripper Foil in the J-PARC RCS

2300

M. Yoshimoto, H. Hotchi, S. Kato, M. Kinsho, K. Okabe, K. Yamamoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

The most important issue in realizing such a MW-class high-power routine beam operation is to keep machine activations within a permissible level, that is, to preserve a better hands-on-maintenance environment. Thus, a large fraction of our effort has been concentrated on reducing and managing beam losses. However the high residual activation is appeared around the stripper foils. It is caused by not primary particles due to the beam losses but secondary particles due to nuclear reaction at the foil. This radio-activation is an intrinsically serious problem for the RCS which adopts the charge exchange multi-turn beam injection scheme with the stripper foil. In this presentation, we report a detail measurement of the residual dose around the stripper foil together with the cause estimated based on simulation studies.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA093

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPVA096

Detection of H⁰ Particles in MEBT2 Chicane of J-PARC Linac

2308

J. Tamura, H. Ao, T. Maruta, A. Miura, T. Morishita, K. Okabe, M. Yoshimoto
JAEA/J-PARC, Tokai-mura, Japan
K. Futatsukawa, T. Miyao
KEK, Ibaraki, Japan
Y. Nemoto
Nippon Advanced Technology Co., Ltd., Tokai, Japan

In the Japan Proton Accelerator Research Complex (J-PARC), H⁰ particles generated by collisions of accelerated H⁻ beams with residual gases are considered as one of the key factors of the residual radiation in the high energy accelerating section of the linac. To diagnose the H⁰ particles, the new beam line for analyzing H⁰ and H⁻ particles was installed in the second medium energy beam transport (MEBT2), which is the matching section from the separated-type drift tube linac (SDTL) to the annular-ring coupled structure linac (ACS). The analysis line consists of four dipole magnets for giving the H⁻ beam chicane orbit, and a wire scanner monitor (WSM) for measuring the horizontal shift of the H⁻ beam. To detect the H⁰ particles, a carbon plate is installed to the WSM. In the beam commissioning, we detected the signals of H⁰ particles penetrating the plate and observed the transition of the signal with various vacuum condition in the SDTL section.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA096

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEOAA3

Realizing a High-Intensity Low-Emittance Beam in the J-PARC 3-GeV RCS

2470

H. Hotchi, H. Harada, S. Kato, K. Okabe, P.K. Saha, Y. Shobuda, F. Tamura, N. Tani, Y. Watanabe, M. Yoshimoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

The J-PARC 3-GeV rapid cycling synchrotron (RCS) has two functions; one as a proton driver to produce pulsed muons and neutrons, and the other as an injector to the following 50-GeV main ring (MR). RCS is now intensively developing a high-intensity beam test to realize a high-intensity low-emittance beam with less beam halo required from MR. This paper presents the recent experimental results, together with detailed discussions for the emittance growth and its mitigation mechanisms.

Slides WEOAA3 [1.732 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEOAA3

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)