HB2012 - List of Authors (Hatakeyama, S.)

Paper

Title

Page

Online Monitoring System for the Waste Beam in the 3-GeV RCS of J-PARC

297

P.K. Saha, H. Harada, S. Hatakeyama, N. Hayashi, H. Hotchi, K. Yamamoto, M. Yoshimoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

We have established two independent methods for monitoring the waste beam of only about 0.4% in the 3 GeV Rapid Cycling Synchrotron of the Japan Proton Accelerator. Although using conventional monitor systems, the measurement technique made it possible for clearly measuring such a waste beam even with significantly low error. One of the method uses a current transformer to measure the waste beam as a whole, while the other one uses a multi-wire profile monitor for clearly measuring beam profiles of both un-stripped and partially stripped components of the waste beam. While the raw signal measured by a CT (current transformer) contains a large noise, an FFT (Fast Fourier Transformation) analysis made it possible to clearly identify the beam signal corresponding to the frequency of the intermediate pulse. The waste beam was measured to be (0.38±0.03)%. Being non destructive, the 1st method is efficiently operating for online monitoring of the waste beam during the RCS user operation so as to directly know the the stripper foil condition and would have great importance for higher power operation.

Slides TUO1C02 [2.687 MB]

THO1B03

Measurement of Optics Errors and Space Charge Effects

517

K. Ohmi, Y. Sato, J. Takano
KEK, Ibaraki, Japan
S. Hatakeyama
JAEA/J-PARC, Tokai-mura, Japan

Beta function and x-y coupling are measured using turn-by-turn monitor system in J-PARC MR. Errors of the optics parameters induce to undesirable resonances due to lattice nonlinear magnets and space charge force. We estimate the resonance strength and the degradation of emittance growth and beam loss.

Slides THO1B03 [2.240 MB]

THO1C06

Recent Commissioning of High-intensity Proton Beams in J-PARC Main Ring

575

Y. Sato, K. Hara, Y. Hashimoto, Y. Hori, S. Igarashi, K. Ishii, N. Kamikubota, T. Koseki, Y. Kurimoto, K. Niki, K. Ohmi, C. Ohmori, M. Okada, M. Shimamoto, M.J. Shirakata, T. Sugimoto, J. Takano, M. Tejima, T. Toyama, M. Uota, S. Yamada, N. Yamamoto, M. Yoshii
KEK, Tokai, Ibaraki, Japan
S. Hatakeyama, H. Hotchi, F. Tamura
JAEA/J-PARC, Tokai-mura, Japan
S. Nakamura, K. Satou
J-PARC, KEK & JAEA, Ibaraki-ken, Japan

J-PARC main ring (MR) provides high power proton beams of 200 kW to the neutrino experiment. Beam losses were well managed within capacity of collimation system. Since this beam power was achieved by shortening the repetition rate, following tunings had been applied in order to reduce the beam losses, such as improvement of tune flatness, chromaticity correction, upgrades of injection kickers, dynamic bunch-by-bunch feed-back to suppress transverse oscillation, beam loading compensation using feed-forward technique, and balancing the collimators of MR and the injection beam transport line. The dynamic bunch-by-bunch feed-back was effective to reduce the beam losses to one-tenth during injection and beginning of acceleration. With the beam loading compensation, impedance seen by the beam was significantly reduced, longitudinal oscillations were damped, and the beam power was increased over 5% without increasing the beam losses. Monitors were upgraded to find time structure and location of the beam losses, even in first several turns after each injection. In this presentation these commissioning procedures and beam dynamics simulations are shown, and our upgrade plan is discussed.

Slides THO1C06 [2.193 MB]

Paper	Title	Page
TUO1C02	Online Monitoring System for the Waste Beam in the 3-GeV RCS of J-PARC	297
	P.K. Saha, H. Harada, S. Hatakeyama, N. Hayashi, H. Hotchi, K. Yamamoto, M. Yoshimoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	We have established two independent methods for monitoring the waste beam of only about 0.4% in the 3 GeV Rapid Cycling Synchrotron of the Japan Proton Accelerator. Although using conventional monitor systems, the measurement technique made it possible for clearly measuring such a waste beam even with significantly low error. One of the method uses a current transformer to measure the waste beam as a whole, while the other one uses a multi-wire profile monitor for clearly measuring beam profiles of both un-stripped and partially stripped components of the waste beam. While the raw signal measured by a CT (current transformer) contains a large noise, an FFT (Fast Fourier Transformation) analysis made it possible to clearly identify the beam signal corresponding to the frequency of the intermediate pulse. The waste beam was measured to be (0.38±0.03)%. Being non destructive, the 1st method is efficiently operating for online monitoring of the waste beam during the RCS user operation so as to directly know the the stripper foil condition and would have great importance for higher power operation.
	Slides TUO1C02 [2.687 MB]

THO1B03	Measurement of Optics Errors and Space Charge Effects	517
	K. Ohmi, Y. Sato, J. Takano KEK, Ibaraki, Japan S. Hatakeyama JAEA/J-PARC, Tokai-mura, Japan
	Beta function and x-y coupling are measured using turn-by-turn monitor system in J-PARC MR. Errors of the optics parameters induce to undesirable resonances due to lattice nonlinear magnets and space charge force. We estimate the resonance strength and the degradation of emittance growth and beam loss.
	Slides THO1B03 [2.240 MB]

THO1C06	Recent Commissioning of High-intensity Proton Beams in J-PARC Main Ring	575
	Y. Sato, K. Hara, Y. Hashimoto, Y. Hori, S. Igarashi, K. Ishii, N. Kamikubota, T. Koseki, Y. Kurimoto, K. Niki, K. Ohmi, C. Ohmori, M. Okada, M. Shimamoto, M.J. Shirakata, T. Sugimoto, J. Takano, M. Tejima, T. Toyama, M. Uota, S. Yamada, N. Yamamoto, M. Yoshii KEK, Tokai, Ibaraki, Japan S. Hatakeyama, H. Hotchi, F. Tamura JAEA/J-PARC, Tokai-mura, Japan S. Nakamura, K. Satou J-PARC, KEK & JAEA, Ibaraki-ken, Japan
	J-PARC main ring (MR) provides high power proton beams of 200 kW to the neutrino experiment. Beam losses were well managed within capacity of collimation system. Since this beam power was achieved by shortening the repetition rate, following tunings had been applied in order to reduce the beam losses, such as improvement of tune flatness, chromaticity correction, upgrades of injection kickers, dynamic bunch-by-bunch feed-back to suppress transverse oscillation, beam loading compensation using feed-forward technique, and balancing the collimators of MR and the injection beam transport line. The dynamic bunch-by-bunch feed-back was effective to reduce the beam losses to one-tenth during injection and beginning of acceleration. With the beam loading compensation, impedance seen by the beam was significantly reduced, longitudinal oscillations were damped, and the beam power was increased over 5% without increasing the beam losses. Monitors were upgraded to find time structure and location of the beam losses, even in first several turns after each injection. In this presentation these commissioning procedures and beam dynamics simulations are shown, and our upgrade plan is discussed.
	Slides THO1C06 [2.193 MB]