IPAC2019 - List of Authors (Moriya, 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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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
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WEPGW033	Development of the Bunch Shape Monitor Using the Carbon-Nano Tube Wire	2543
	R. Kitamura, N. Hayashi, K. Hirano, Y. Kondo, K. Moriya, H. Oguri JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan K. Futatsukawa, T. Miyao, M. Otani KEK, Tokai, Ibaraki, Japan S. Kosaka, Y. Nemoto Nippon Advanced Technology Co., Ltd., Tokai, Japan
	A bunch shape monitor (BSM) is one of the important instruments to measure the longitudinal phase space distribution. The information of the bunch length measured by the BSM is useful to tune phases of the accelerating cavities in the linear accelerator. For example, in the J-PARC linac, three BSM’s using the tungsten wire are installed and tested at the ACS section to measure the bunch shapes between the accelerating cavities. However, this conventional BSM is hard to measure the bunch shape of H⁻ beam with 3 MeV at the beam transport between the RFQ and DTL sections, because the wire is broken around the center region of the beam. The new BSM using the carbon-nano-tube (CNT) wire is being developed to be able to measure the bunch shape of the H⁻ beam with 3 MeV. One challenge to introduce the CNT wire for the BSM is the measure to the discharge. The careful attention should be paid to apply the high voltage of 10 kV to the CNT wire. The several measures are taken to suppress the discharge from the wire and operate the CNT-BSM. This presentation reports the current status of the development and future prospective for the CNT-BSM.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW033
About •	paper received ※ 15 May 2019 paper accepted ※ 22 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

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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)

WEPGW033

Development of the Bunch Shape Monitor Using the Carbon-Nano Tube Wire

2543

R. Kitamura, N. Hayashi, K. Hirano, Y. Kondo, K. Moriya, H. Oguri
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
K. Futatsukawa, T. Miyao, M. Otani
KEK, Tokai, Ibaraki, Japan
S. Kosaka, Y. Nemoto
Nippon Advanced Technology Co., Ltd., Tokai, Japan

A bunch shape monitor (BSM) is one of the important instruments to measure the longitudinal phase space distribution. The information of the bunch length measured by the BSM is useful to tune phases of the accelerating cavities in the linear accelerator. For example, in the J-PARC linac, three BSM’s using the tungsten wire are installed and tested at the ACS section to measure the bunch shapes between the accelerating cavities. However, this conventional BSM is hard to measure the bunch shape of H⁻ beam with 3 MeV at the beam transport between the RFQ and DTL sections, because the wire is broken around the center region of the beam. The new BSM using the carbon-nano-tube (CNT) wire is being developed to be able to measure the bunch shape of the H⁻ beam with 3 MeV. One challenge to introduce the CNT wire for the BSM is the measure to the discharge. The careful attention should be paid to apply the high voltage of 10 kV to the CNT wire. The several measures are taken to suppress the discharge from the wire and operate the CNT-BSM. This presentation reports the current status of the development and future prospective for the CNT-BSM.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW033

About •

paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

Export •

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