IPAC2017 - List of Authors (Harada, H.)

Paper	Title	Page
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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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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WEPIK014	Coupled Bunch Instability and Its Cure at J-PARC RCS	2946
	Y. Shobuda, H. Harada, H. Hotchi, P.K. Saha, T. Takayanagi, F. Tamura, N. Tani, T. Togashi, Y. Watanabe, K. Yamamoto, M. Yamamoto JAEA/J-PARC, Tokai-mura, Japan Y.H. Chin, Y. Irie, T. Toyama KEK, Tokai, Ibaraki, Japan
	The RCS at J-PARC is a kicker-impedance dominant machine, which violates the impedance budget from a classical viewpoint. Nevertheless, we have recently succeeded to accelerate a 1-MW equivalent beam by making maximum use of the space charge effect on the beam instabilities. In this report, we explain the manipulation to suppress the beam instability, at first. Then, we discuss some issues to suppress the beam instabilities for beams with much smaller transverse emittance, as well as the present status of our efforts to reduce the kicker impedance toward the realization of the higher beam power at the RCS.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK014
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WEPIK074	Twiss Parameter Measurement and Application to Space Charge Dynamics	3101
	K. Ohmi, S. Igarashi, T. Toyama KEK, Tokai, Ibaraki, Japan H. Harada, S. Hatakeyama JAEA/J-PARC, Tokai-mura, Japan N. Kuroo UTTAC, Tsukuba, Ibaraki, Japan Y. Sato J-PARC, KEK & JAEA, Ibaraki-ken, Japan R. Tomás, A. Wegscheider CERN, Geneva, Switzerland
	We are looking for feasible and quantitative method to evaluate space charge induced beam loss in J-PARC MR. One possible way is space charge simulation and theory based on measured Twiss parameter. Twiss parameter measurement using turn-by-turn monitors is presented. Resonance strengths of lattice magnets and space charge force are estimated by the measured Twiss parameters. Emittance growth and beam loss under the resonance strengths are discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK074
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Paper

Title

Page

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)

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)

WEPIK014

Coupled Bunch Instability and Its Cure at J-PARC RCS

2946

Y. Shobuda, H. Harada, H. Hotchi, P.K. Saha, T. Takayanagi, F. Tamura, N. Tani, T. Togashi, Y. Watanabe, K. Yamamoto, M. Yamamoto
JAEA/J-PARC, Tokai-mura, Japan
Y.H. Chin, Y. Irie, T. Toyama
KEK, Tokai, Ibaraki, Japan

The RCS at J-PARC is a kicker-impedance dominant machine, which violates the impedance budget from a classical viewpoint. Nevertheless, we have recently succeeded to accelerate a 1-MW equivalent beam by making maximum use of the space charge effect on the beam instabilities. In this report, we explain the manipulation to suppress the beam instability, at first. Then, we discuss some issues to suppress the beam instabilities for beams with much smaller transverse emittance, as well as the present status of our efforts to reduce the kicker impedance toward the realization of the higher beam power at the RCS.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK014

Export •

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

WEPIK074

Twiss Parameter Measurement and Application to Space Charge Dynamics

3101

K. Ohmi, S. Igarashi, T. Toyama
KEK, Tokai, Ibaraki, Japan
H. Harada, S. Hatakeyama
JAEA/J-PARC, Tokai-mura, Japan
N. Kuroo
UTTAC, Tsukuba, Ibaraki, Japan
Y. Sato
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
R. Tomás, A. Wegscheider
CERN, Geneva, Switzerland

We are looking for feasible and quantitative method to evaluate space charge induced beam loss in J-PARC MR. One possible way is space charge simulation and theory based on measured Twiss parameter. Twiss parameter measurement using turn-by-turn monitors is presented. Resonance strengths of lattice magnets and space charge force are estimated by the measured Twiss parameters. Emittance growth and beam loss under the resonance strengths are discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK074

Export •

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