IPAC2017 - List of Authors (Yamamoto, K.)

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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TUPVA090	Performance and Status of the J-PARC Accelerators	2290
	K. Hasegawa, N. Hayashi, M. Kinsho, H. Oguri, K. Yamamoto, Y. Yamazaki JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan Y. Hori, N. Yamamoto J-PARC, KEK & JAEA, Ibaraki-ken, Japan T. Koseki, F. Naito KEK, Tokai, Ibaraki, Japan
	The J-PARC is a high intensity proton facility and the accelerator consists of a 400 MeV linac, a 3 GeV Rapid Cycling Synchrotron (RCS) and a Main Ring Synchrotron (MR). We have taken many hardware upgrades. The beam powers for the neutrino experiment and hadron experiment from the MR have been steadily increased by tuning and reducing beam losses. The designed 1 MW equivalent beam was demonstrated and user program was performed at 500 kW from the RCS to the neutron and muon experiments. We have experienced many failures and troubles, however, to impede full potential and high availability. In this report, operational performance and status of the J-PARC accelerators are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA090
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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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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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WEPVA063	Development of a New Pulsed Power Supply with the SiC-MOSFET	3412
	T. Takayanagi, K. Horino, J. Kamiya, M. Kinsho, T. Ueno, K. Yamamoto JAEA/J-PARC, Tokai-mura, Japan Y. Mushibe, A. Tokuchi Pulsed Power Japan Laboratory Ltd., Kusatsu-shi Shiga, Japan
	A new power supply has been developed using linear transformer driver (LTD) technology that adopts SiC-MOSFETs and capacitors without a thyratron switch or a pulse forming network (PFN) device. A new power supply was also designed by connecting the SiC-MOSFETs and the LTD modules in parallel-series. The output voltage and current were 40 kV and 4 kA, respectively with a pulse width of 1500 nsec at a repetition rate of 25 Hz. Furthermore, by adjusting the correction module, to an output voltage per stage of 1/1000, a resolution of the voltage correction of ±0.1 % could be achieved. It was possible to output the current with arbitrary timing by using a trigger input for each LTD module. As a result, fine adjustment of the output voltage waveform was possible within the order of nanoseconds. This new power supply with high voltage output, cur-rent output, and very fast pulse operation is one of the most important key technologies for a kicker system using SiC-MOSFETs. The design and preliminary test results of this prototype power supply are presented here.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPVA063
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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)

TUPVA090

Performance and Status of the J-PARC Accelerators

2290

K. Hasegawa, N. Hayashi, M. Kinsho, H. Oguri, K. Yamamoto, Y. Yamazaki
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
Y. Hori, N. Yamamoto
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
T. Koseki, F. Naito
KEK, Tokai, Ibaraki, Japan

The J-PARC is a high intensity proton facility and the accelerator consists of a 400 MeV linac, a 3 GeV Rapid Cycling Synchrotron (RCS) and a Main Ring Synchrotron (MR). We have taken many hardware upgrades. The beam powers for the neutrino experiment and hadron experiment from the MR have been steadily increased by tuning and reducing beam losses. The designed 1 MW equivalent beam was demonstrated and user program was performed at 500 kW from the RCS to the neutron and muon experiments. We have experienced many failures and troubles, however, to impede full potential and high availability. In this report, operational performance and status of the J-PARC accelerators are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA090

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)

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)

WEPVA063

Development of a New Pulsed Power Supply with the SiC-MOSFET

3412

T. Takayanagi, K. Horino, J. Kamiya, M. Kinsho, T. Ueno, K. Yamamoto
JAEA/J-PARC, Tokai-mura, Japan
Y. Mushibe, A. Tokuchi
Pulsed Power Japan Laboratory Ltd., Kusatsu-shi Shiga, Japan

A new power supply has been developed using linear transformer driver (LTD) technology that adopts SiC-MOSFETs and capacitors without a thyratron switch or a pulse forming network (PFN) device. A new power supply was also designed by connecting the SiC-MOSFETs and the LTD modules in parallel-series. The output voltage and current were 40 kV and 4 kA, respectively with a pulse width of 1500 nsec at a repetition rate of 25 Hz. Furthermore, by adjusting the correction module, to an output voltage per stage of 1/1000, a resolution of the voltage correction of ±0.1 % could be achieved. It was possible to output the current with arbitrary timing by using a trigger input for each LTD module. As a result, fine adjustment of the output voltage waveform was possible within the order of nanoseconds. This new power supply with high voltage output, cur-rent output, and very fast pulse operation is one of the most important key technologies for a kicker system using SiC-MOSFETs. The design and preliminary test results of this prototype power supply are presented here.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPVA063

Export •

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