IBIC2012 - List of Authors (Hatakeyama, S.)

Paper

Title

Page

MOPA23

Measurement of X-Y Coupling at J-PARC MR

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

In high intensity proton ring, nonlinear accelerator elements and space charge force in the presence of x-y coupling induces skew resonances. Degradation of the beam performance, beam loss enlargement, is caused by the resonances. x-y coupling has been measured in whole ring of J-PARC MR. We discuss the measurement and the effect of x-y coupling in the beam performance.

MOPA26

Performance and Upgrade of BPMs at the J-PARC MR

T. Toyama, Y. Hashimoto
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
K. Hanamura
MELCO SC, Tsukuba, Japan
S. Hatakeyama
JAEA/J-PARC, Tokai-mura, Japan
M. Okada, M. Tejima
KEK, Ibaraki, Japan

Since recovery from the great earthquake 2011.3.11, proton beam, more than 10¹⁴ ppp, is accelerated up to 30 GeV at the J-PARC MR. The BPMs were originally designed with the external capacitors. The aim was to improve the position response in wider frequencies and to get an adequate output voltage at the design intensity, 4x10¹³ ppb. It was modified, however, not to have the capacitors. Therefore we have sufficient signal intensity from low intensity beams of the initial beam commissioning, but too large from the design intensity beam. The processing circuits (BPMC) have to accommodate those output signals from high intensity beams. We are adding the attenuator-LPFs just before the BPMC. This paper will describe these additional attenuator-LPFs. In connection with the MR collimator upgrade, some BPMs are re-allocated. This process is also reported.

Paper	Title	Page
MOPA23	Measurement of X-Y Coupling at J-PARC MR
	K. Ohmi KEK, Ibaraki, Japan S. Hatakeyama JAEA/J-PARC, Tokai-mura, Japan
	In high intensity proton ring, nonlinear accelerator elements and space charge force in the presence of x-y coupling induces skew resonances. Degradation of the beam performance, beam loss enlargement, is caused by the resonances. x-y coupling has been measured in whole ring of J-PARC MR. We discuss the measurement and the effect of x-y coupling in the beam performance.

MOPA26	Performance and Upgrade of BPMs at the J-PARC MR
	T. Toyama, Y. Hashimoto J-PARC, KEK & JAEA, Ibaraki-ken, Japan K. Hanamura MELCO SC, Tsukuba, Japan S. Hatakeyama JAEA/J-PARC, Tokai-mura, Japan M. Okada, M. Tejima KEK, Ibaraki, Japan
	Since recovery from the great earthquake 2011.3.11, proton beam, more than 10¹⁴ ppp, is accelerated up to 30 GeV at the J-PARC MR. The BPMs were originally designed with the external capacitors. The aim was to improve the position response in wider frequencies and to get an adequate output voltage at the design intensity, 4x10¹³ ppb. It was modified, however, not to have the capacitors. Therefore we have sufficient signal intensity from low intensity beams of the initial beam commissioning, but too large from the design intensity beam. The processing circuits (BPMC) have to accommodate those output signals from high intensity beams. We are adding the attenuator-LPFs just before the BPMC. This paper will describe these additional attenuator-LPFs. In connection with the MR collimator upgrade, some BPMs are re-allocated. This process is also reported.