HB2016 - List of Authors (Kato, S.)

Paper	Title	Page
TUPM5X01	Injection Painting Improvements in the J-PARC RCS	299
	S. Kato, K. Horino, H. Hotchi, M. Kinsho, K. Okabe, P.K. Saha, Y. Shobuda, T. Takayanagi, T. Tobita, T. Ueno JAEA/J-PARC, Tokai-mura, Japan H. Harada JAEA, Ibaraki-ken, Japan
	In the J-PARC 3GeV RCS, the injection painting is essential method for the reduction of the space charge force. In this method, the H⁻ beam from Linac is arranged on the large phase space area of the ring orbit during multiple turns. To implement this method, painting magnets form the time variable beam orbit. Therefore, the precise output current control of the magnet power supply is required. Because the power supply controlled by mainly feedforward signal is operated, we developed the iterative tuning method for the optimum feedforward parameter determination. As a result, we could reduce the tracking error of the current compared to before. Furthermore, to improve the accuracy of the painting area size, we applied the output readjustment additionally. Because the current monitor value of the power supply was different from the actual magnetic field due to the delay in the circuit and the leakage field, we corrected the tracking of the current based on the measured painting area size determined by the analysis of the measured COD. As a result, we achieved the precise injection painting. This talk presents these improvement results of the injection painting in the RCS.
	Slides TUPM5X01 [4.122 MB]
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TUPM7X01	An Experimental Plan for 400 MeV H⁻ Stripping to Proton by Using Only Lasers in the J-PARC RCS	310
	P.K. Saha, H. Harada, S. Kato, M. Kinsho JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan Y. Irie, I. Yamane KEK, Ibaraki, Japan
	The 3-GeV RCS (Rapid Cycling Synchrotron) of J-PARC is gradually approaching to the design operation with 1 MW beam power. Studies are ongoing for further higher beam power of 1.5 MW. The injection and extraction energy of RCS is 0.4 and 3 GeV, respectively. Lifetime of the stripper foil is the highest concern beyond 1 MW beam power. We have also already started detail studies of H⁻ stripping to protons by using lasers. However, in order to avoid high magnetic field required in the process of laser-assisted H⁻ stripping to protons, especially for lower H⁻ energies, we are studying the possibilities of using only laser system for 400 MeV H⁻ beam in the RCS. The method is a three step process, similar to that of SNS but lasers are used instead of high field magnets in the 1st (H⁻ to H⁰) and 3rd step (H0* to p). A Nd:YAG laser can be properly used for both 1st and 3rd steps, where commercially available powerful Excimer laser will be used an H⁰ excitation in the 2nd step. Although detail R&D studies are necessary to reach to the ultimate goal, we plan to carry out an experiment in 2017. A detail of the present method, experimental schedule and the expected outcome will be presented.
	Slides TUPM7X01 [3.316 MB]
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THAM6X01	The Path to 1 MW: Beam Loss Control in the J-PARC 3-GeV RCS	480
	H. Hotchi, H. Harada, S. Kato, M. Kinsho, K. Okabe, P.K. Saha, Y. Shobuda, F. Tamura, N. Tani, Y. Watanabe, K. Yamamoto, M. Yamamoto, M. Yoshimoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	The J-PARC 3-GeV RCS started 1-MW beam test from October 2014, and successfully achieved a 1-MW beam acceleration in January 2015. The most important issues in realizing such a high power routine beam operation are control and minimization of beam loss. This talk will present the recent progress of 1-MW beam tuning, especially focusing on our approaches to beam loss issues.
	Slides THAM6X01 [1.849 MB]
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Paper

Title

Page

Injection Painting Improvements in the J-PARC RCS

299

S. Kato, K. Horino, H. Hotchi, M. Kinsho, K. Okabe, P.K. Saha, Y. Shobuda, T. Takayanagi, T. Tobita, T. Ueno
JAEA/J-PARC, Tokai-mura, Japan
H. Harada
JAEA, Ibaraki-ken, Japan

In the J-PARC 3GeV RCS, the injection painting is essential method for the reduction of the space charge force. In this method, the H⁻ beam from Linac is arranged on the large phase space area of the ring orbit during multiple turns. To implement this method, painting magnets form the time variable beam orbit. Therefore, the precise output current control of the magnet power supply is required. Because the power supply controlled by mainly feedforward signal is operated, we developed the iterative tuning method for the optimum feedforward parameter determination. As a result, we could reduce the tracking error of the current compared to before. Furthermore, to improve the accuracy of the painting area size, we applied the output readjustment additionally. Because the current monitor value of the power supply was different from the actual magnetic field due to the delay in the circuit and the leakage field, we corrected the tracking of the current based on the measured painting area size determined by the analysis of the measured COD. As a result, we achieved the precise injection painting. This talk presents these improvement results of the injection painting in the RCS.

Slides TUPM5X01 [4.122 MB]

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

TUPM7X01

An Experimental Plan for 400 MeV H⁻ Stripping to Proton by Using Only Lasers in the J-PARC RCS

310

P.K. Saha, H. Harada, S. Kato, M. Kinsho
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
Y. Irie, I. Yamane
KEK, Ibaraki, Japan

The 3-GeV RCS (Rapid Cycling Synchrotron) of J-PARC is gradually approaching to the design operation with 1 MW beam power. Studies are ongoing for further higher beam power of 1.5 MW. The injection and extraction energy of RCS is 0.4 and 3 GeV, respectively. Lifetime of the stripper foil is the highest concern beyond 1 MW beam power. We have also already started detail studies of H⁻ stripping to protons by using lasers. However, in order to avoid high magnetic field required in the process of laser-assisted H⁻ stripping to protons, especially for lower H⁻ energies, we are studying the possibilities of using only laser system for 400 MeV H⁻ beam in the RCS. The method is a three step process, similar to that of SNS but lasers are used instead of high field magnets in the 1st (H⁻ to H⁰) and 3rd step (H0* to p). A Nd:YAG laser can be properly used for both 1st and 3rd steps, where commercially available powerful Excimer laser will be used an H⁰ excitation in the 2nd step. Although detail R&D studies are necessary to reach to the ultimate goal, we plan to carry out an experiment in 2017. A detail of the present method, experimental schedule and the expected outcome will be presented.

Slides TUPM7X01 [3.316 MB]

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THAM6X01

The Path to 1 MW: Beam Loss Control in the J-PARC 3-GeV RCS

480

H. Hotchi, H. Harada, S. Kato, M. Kinsho, K. Okabe, P.K. Saha, Y. Shobuda, F. Tamura, N. Tani, Y. Watanabe, K. Yamamoto, M. Yamamoto, M. Yoshimoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

The J-PARC 3-GeV RCS started 1-MW beam test from October 2014, and successfully achieved a 1-MW beam acceleration in January 2015. The most important issues in realizing such a high power routine beam operation are control and minimization of beam loss. This talk will present the recent progress of 1-MW beam tuning, especially focusing on our approaches to beam loss issues.

Slides THAM6X01 [1.849 MB]

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