IPAC2018 - List of Authors (Ohmori, C.)

Paper	Title	Page
TUPAK011	Present Status and Future Upgrades of the J-PARC Ring RF Systems	984
	M. Yoshii, M. Furusawa, K. Hara, K. Hasegawa, C. Ohmori, Y. Sugiyama KEK, Tokai, Ibaraki, Japan M. Nomura, T. Shimada, F. Tamura, M. Yamamoto JAEA/J-PARC, Tokai-mura, Japan
	J-PARC is the multipurpose research institutes. 10 years have passed since the user operation started. We have been considering the upgrades for the future and the target beam powers for 3 GeV rapid cycling synchrotron (RCS) and 30GeV Main ring (MR) are 1.5MW and 1.3MW. To achieve a 1.5MW of RCS output beam power, increasing the number of Linac proton particles is necessary. For accelerating such higher beam current, the rf systems in the RCS need to upgrade an accelerating voltage and to take account of heavier beam loading. In case of the MR, increasing the number of proton is not appropriate from the viewpoint of space charge effects. We chose to shorten the MR cycle time. The required RF voltages become almost double. All nine systems have been replaced with the higher accelerating gradient RF systems using a newly developed magnetic alloy material. At present, the proton beam of 470kW is being delivered with a cycle time of 2.48s. Beam powers of MR will plan to aim first at 750KW after replacing the magnet power supplies. But, to realize a 1.3MW beam power, upgrading the RF power sources will be necessary. We present the ring RF system status and their upgrades for the future.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAK011
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TUPAK012	Conceptual Design of a Single-Ended MA Cavity for J-PARC RCS Upgrade	987
	M. Yamamoto, M. Nomura, T. Shimada, F. Tamura JAEA/J-PARC, Tokai-mura, Japan M. Furusawa, K. Hara, K. Hasegawa, C. Ohmori, Y. Sugiyama, M. Yoshii KEK, Tokai, Ibaraki, Japan
	The J-PARC RCS employes Magnetic Alloy (MA) loaded cavities and rf power is fed by vacuum tubes in push-pull operation. The multi-harmonic rf driving and the multi-harmonic beam loading compensation are realized due to the broadband characteristics of the MA. However, the push-pull operation has disadvantages in the multi-harmonics. An unbalance of the anode voltage swing remarkably appears at very high intensity beam acceleration. In order to avoid the unbalance, a single-ended MA cavity is considered for the RCS beam power upgrade because no unbalance arises intrinsically. We will describe the conceptual design of the single-end MA cavity for the RCS upgrade.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAK012
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WEPAL003	Baseband Simulation Model of the Vector RF Voltage Control System for the J-PARC RCS	2144
	F. Tamura, M. Nomura, T. Shimada, M. Yamamoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan M. Furusawa, K. Hara, K. Hasegawa, C. Ohmori, Y. Sugiyama, M. Yoshii KEK, Tokai, Ibaraki, Japan
	Vector rf voltage feedback control for the wideband magnetic alloy cavity of the J-PARC RCS is considered to be employed to compensate the heavy beam loading caused by high intensity proton beams. A prototype system of multiharmonic rf vector voltage control has been developed and is under testing. To characterize the system performance, full rf simulations could be performed by software like Simulink, while the software is proprietary and expensive. Also, it requires much computing power and time. We performed the simplified baseband simulations of the system in z-domain by using free software, Scilab and Python control library. It seems to be beneficial for searching the parameters that the baseband simulation can be performed quickly. In this presentation, we present the setup and results of the simulations. The simulations well reproduce the open and closed loop responses of the prototype system.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL003
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Present Status and Future Upgrades of the J-PARC Ring RF Systems

984

M. Yoshii, M. Furusawa, K. Hara, K. Hasegawa, C. Ohmori, Y. Sugiyama
KEK, Tokai, Ibaraki, Japan
M. Nomura, T. Shimada, F. Tamura, M. Yamamoto
JAEA/J-PARC, Tokai-mura, Japan

J-PARC is the multipurpose research institutes. 10 years have passed since the user operation started. We have been considering the upgrades for the future and the target beam powers for 3 GeV rapid cycling synchrotron (RCS) and 30GeV Main ring (MR) are 1.5MW and 1.3MW. To achieve a 1.5MW of RCS output beam power, increasing the number of Linac proton particles is necessary. For accelerating such higher beam current, the rf systems in the RCS need to upgrade an accelerating voltage and to take account of heavier beam loading. In case of the MR, increasing the number of proton is not appropriate from the viewpoint of space charge effects. We chose to shorten the MR cycle time. The required RF voltages become almost double. All nine systems have been replaced with the higher accelerating gradient RF systems using a newly developed magnetic alloy material. At present, the proton beam of 470kW is being delivered with a cycle time of 2.48s. Beam powers of MR will plan to aim first at 750KW after replacing the magnet power supplies. But, to realize a 1.3MW beam power, upgrading the RF power sources will be necessary. We present the ring RF system status and their upgrades for the future.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAK011

Export •

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

TUPAK012

Conceptual Design of a Single-Ended MA Cavity for J-PARC RCS Upgrade

987

M. Yamamoto, M. Nomura, T. Shimada, F. Tamura
JAEA/J-PARC, Tokai-mura, Japan
M. Furusawa, K. Hara, K. Hasegawa, C. Ohmori, Y. Sugiyama, M. Yoshii
KEK, Tokai, Ibaraki, Japan

The J-PARC RCS employes Magnetic Alloy (MA) loaded cavities and rf power is fed by vacuum tubes in push-pull operation. The multi-harmonic rf driving and the multi-harmonic beam loading compensation are realized due to the broadband characteristics of the MA. However, the push-pull operation has disadvantages in the multi-harmonics. An unbalance of the anode voltage swing remarkably appears at very high intensity beam acceleration. In order to avoid the unbalance, a single-ended MA cavity is considered for the RCS beam power upgrade because no unbalance arises intrinsically. We will describe the conceptual design of the single-end MA cavity for the RCS upgrade.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAK012

Export •

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

WEPAL003

Baseband Simulation Model of the Vector RF Voltage Control System for the J-PARC RCS

2144

F. Tamura, M. Nomura, T. Shimada, M. Yamamoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
M. Furusawa, K. Hara, K. Hasegawa, C. Ohmori, Y. Sugiyama, M. Yoshii
KEK, Tokai, Ibaraki, Japan

Vector rf voltage feedback control for the wideband magnetic alloy cavity of the J-PARC RCS is considered to be employed to compensate the heavy beam loading caused by high intensity proton beams. A prototype system of multiharmonic rf vector voltage control has been developed and is under testing. To characterize the system performance, full rf simulations could be performed by software like Simulink, while the software is proprietary and expensive. Also, it requires much computing power and time. We performed the simplified baseband simulations of the system in z-domain by using free software, Scilab and Python control library. It seems to be beneficial for searching the parameters that the baseband simulation can be performed quickly. In this presentation, we present the setup and results of the simulations. The simulations well reproduce the open and closed loop responses of the prototype system.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL003

Export •

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