IPAC2019 - List of Authors (Okabe, K.)

Paper	Title	Page
MOPGW035	Coupling Impedance of the Collimator Without RF-Shields at the RCS in J-PARC	163
	Y. Shobuda, J. Kamiya, K. Moriya, K. Okabe JAEA/J-PARC, Tokai-mura, Japan
	All holes on the chamber walls of synchrotrons should be filled with the radiofrequency (RF)-shields to suppress coupling impedances that excite beam instabilities. In a synchrotron, titanium nitride (TiN)-coated RF-shields are installed with collimators. If the holes, through which the collimator jaw enters and exits the chamber, are filled with such RF-shields, the shields may break down as the dynamic coefficient of TiN increases in vacuum. At the Rapid Cycling Synchrotron (RCS), the RF-shields are eliminated from the collimator after demonstrating that the effect due to the RF-shields is negligible on the impedance at low frequencies.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW035
About •	paper received ※ 28 April 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019
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MOPRB019	Beam Optics Study on FFA-MERIT Ring	613
	H. Okita, Y. Ishi, Y. Kuriyama, Y. Mori, Y. Ono, A. Taniguchi, T. Uesugi Kyoto University, Research Reactor Institute, Osaka, Japan N. Ikeda, Y. Yonemura Kyushu University, Department of Applied Quantum Physics and Nuclear Engineering, Fukuoka, Japan M. Kinsho, K. Okabe, M. Yoshimoto JAEA/J-PARC, Tokai-mura, Japan Y. Miyake KEK, Tokai, Ibaraki, Japan M. Muto New Affiliation Request Pending, -TBS-, Unknown A. Sato Osaka University, Osaka, Japan
	Funding: This work was funded by ImPACT Program of Council for Science, Technology and Innovation (Cabinet Office, Government of Japan). Intense negative muon source MERIT (Multiplex Energy Recovery Internal Target) for the nuclear transformation to mitigate the long lived fission products from nuclear plants has been proposed. For the purpose of proof-of-principle of MERIT scheme, FFA ring has been developed. The results of beam optics study for MERIT ring will be reported in this conference.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB019
About •	paper received ※ 30 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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TUPTS027	Progress of J-PARC LINAC Commissioning	1990
	Y. Liu KEK/JAEA, Ibaraki-Ken, Japan Z. Fang, K. Futatsukawa, T. Miyao, M. Otani, T. Shibata KEK, Tokai, Ibaraki, Japan T. Ito, A. Miura, T. Morishita, K. Moriya, K. Okabe, J. Tamura JAEA/J-PARC, Tokai-mura, Japan
	After energy and intensity upgrade to 400MeV and 50mA respectively, J-PARC linac were ready for 1 MW beam power from RCS. J-PARC is now successfully operated at 50mA/400MeV for 500kW at neutron target, and on the way to 1MW. The next milestones 1.2 and 1.5MW from RCS are relying on feasibility and property of increase of peak current to 60 mA and the pulse width to 600us in linac. Beam studies were carried out at linac to study the initial beam parameters from ion source/RFQ, to find the optimized lattice and matching, to clarify beam loss source and to mitigate the loss/residue dose for the power upgrade.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS027
About •	paper received ※ 17 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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WEPGW032	Evaluation of 2-D Transverse Beam Profile Monitor Using Gas Sheet at J-PARC LINAC	2539
	J. Kamiya, Y. Hikichi, M. Kinsho, K. Moriya, N. Ogiwara, K. Okabe JAEA/J-PARC, Tokai-mura, Japan K. Wada Tokyo Electronics Co. Ltd., Kokubunji, Tokyo, Japan I. Yamada Doshisha University, Graduate School of Engineering, Kyoto, Japan
	A transverse beam profile monitor, which detects ions or luminescence generated by the interaction between the beam and the gas molecules distributed in a sheet shape, has been developed in the J-PARC LINAC. To know about the gas density distribution of the sheet-shaped gas, which affects the intensity distribution of the detected signal, the calculation by the Monte Carlo simulation code was performed. The calculation results showed that the gas with a narrow width along beam direction distributes enough uniformly within a realistic beam cross-sectional size. In addition, the unsaturated region against the MCP voltage and the injected gas pressure are evaluated based on the measurement with a beam. The results showed that the measurement in the low injected gas pressure with the appropriate applied voltage range is important to measure the beam profile in the unsaturated region.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW032
About •	paper received ※ 29 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Coupling Impedance of the Collimator Without RF-Shields at the RCS in J-PARC

163

Y. Shobuda, J. Kamiya, K. Moriya, K. Okabe
JAEA/J-PARC, Tokai-mura, Japan

All holes on the chamber walls of synchrotrons should be filled with the radiofrequency (RF)-shields to suppress coupling impedances that excite beam instabilities. In a synchrotron, titanium nitride (TiN)-coated RF-shields are installed with collimators. If the holes, through which the collimator jaw enters and exits the chamber, are filled with such RF-shields, the shields may break down as the dynamic coefficient of TiN increases in vacuum. At the Rapid Cycling Synchrotron (RCS), the RF-shields are eliminated from the collimator after demonstrating that the effect due to the RF-shields is negligible on the impedance at low frequencies.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW035

About •

paper received ※ 28 April 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019

Export •

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

MOPRB019

Beam Optics Study on FFA-MERIT Ring

613

H. Okita, Y. Ishi, Y. Kuriyama, Y. Mori, Y. Ono, A. Taniguchi, T. Uesugi
Kyoto University, Research Reactor Institute, Osaka, Japan
N. Ikeda, Y. Yonemura
Kyushu University, Department of Applied Quantum Physics and Nuclear Engineering, Fukuoka, Japan
M. Kinsho, K. Okabe, M. Yoshimoto
JAEA/J-PARC, Tokai-mura, Japan
Y. Miyake
KEK, Tokai, Ibaraki, Japan
M. Muto
New Affiliation Request Pending, -TBS-, Unknown
A. Sato
Osaka University, Osaka, Japan

Funding: This work was funded by ImPACT Program of Council for Science, Technology and Innovation (Cabinet Office, Government of Japan).
Intense negative muon source MERIT (Multiplex Energy Recovery Internal Target) for the nuclear transformation to mitigate the long lived fission products from nuclear plants has been proposed. For the purpose of proof-of-principle of MERIT scheme, FFA ring has been developed. The results of beam optics study for MERIT ring will be reported in this conference.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB019

About •

paper received ※ 30 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

Export •

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

TUPTS027

Progress of J-PARC LINAC Commissioning

1990

Y. Liu
KEK/JAEA, Ibaraki-Ken, Japan
Z. Fang, K. Futatsukawa, T. Miyao, M. Otani, T. Shibata
KEK, Tokai, Ibaraki, Japan
T. Ito, A. Miura, T. Morishita, K. Moriya, K. Okabe, J. Tamura
JAEA/J-PARC, Tokai-mura, Japan

After energy and intensity upgrade to 400MeV and 50mA respectively, J-PARC linac were ready for 1 MW beam power from RCS. J-PARC is now successfully operated at 50mA/400MeV for 500kW at neutron target, and on the way to 1MW. The next milestones 1.2 and 1.5MW from RCS are relying on feasibility and property of increase of peak current to 60 mA and the pulse width to 600us in linac. Beam studies were carried out at linac to study the initial beam parameters from ion source/RFQ, to find the optimized lattice and matching, to clarify beam loss source and to mitigate the loss/residue dose for the power upgrade.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS027

About •

paper received ※ 17 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

Export •

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

WEPGW032

Evaluation of 2-D Transverse Beam Profile Monitor Using Gas Sheet at J-PARC LINAC

2539

J. Kamiya, Y. Hikichi, M. Kinsho, K. Moriya, N. Ogiwara, K. Okabe
JAEA/J-PARC, Tokai-mura, Japan
K. Wada
Tokyo Electronics Co. Ltd., Kokubunji, Tokyo, Japan
I. Yamada
Doshisha University, Graduate School of Engineering, Kyoto, Japan

A transverse beam profile monitor, which detects ions or luminescence generated by the interaction between the beam and the gas molecules distributed in a sheet shape, has been developed in the J-PARC LINAC. To know about the gas density distribution of the sheet-shaped gas, which affects the intensity distribution of the detected signal, the calculation by the Monte Carlo simulation code was performed. The calculation results showed that the gas with a narrow width along beam direction distributes enough uniformly within a realistic beam cross-sectional size. In addition, the unsaturated region against the MCP voltage and the injected gas pressure are evaluated based on the measurement with a beam. The results showed that the measurement in the low injected gas pressure with the appropriate applied voltage range is important to measure the beam profile in the unsaturated region.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW032

About •

paper received ※ 29 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

Export •

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