DIPAC2011 - List of Authors (Obina, T.)

Paper

Title

Page

Beam Profile Measurement during Top-up Injection with a Pulsed Sextupole Magnet

305

R. Takai, K. Harada, T. Honda, Y. Kobayashi, S. Nagahashi, N. Nakamura, T. Obina, A. Ueda
KEK, Ibaraki, Japan
H. Takaki
ISSP/SRL, Chiba, Japan

A beam injection scheme using a pulsed multipole magnet is suitable for the top-up injection because a disturbance to the stored beam is much smaller than that of the conventional scheme using several kicker magnets. At the Photon Factory storage ring, the top-up injection with a pulsed sextupole magnet (PSM) has been used for the user operation since January 2011. In order to ascertain the effect of the PSM injection, we measured turn-by-turn stored beam profiles following the injection kick by using a fast-gated camera. As a result, it was demonstrated that the PSM injection dramatically decreases not only the coherent dipole oscillation but also the beam profile modulation, as expected from the beam tracking simulation.

TUPD73

Fast Orbit Stabilization System for Tandem APPLE-II Undulators at the KEK-PF

479

T. Obina, K. Harada, R. Takai
KEK, Ibaraki, Japan

A rapid-polarization switching source has been developed in the KEK-PF 2.5-GeV electron storage ring. The source consists of two tandem APPLE-II type elliptically polarizing undulators (EPU) and five fast kicker magnets. The kicker magnets produce a local bump orbit at the frequency up to 100 Hz. Amplitude and phase of these magnets must be tuned precisely in order to minimize the leakage of residual orbit outside of the kicker bump. A fast orbit stabilization system which consists of ADC/FPGA/DAC are also developed to reduce the remaining orbit fluctuations in vertical and horizontal planes. In this paper, design and the preliminary result of the fast orbit compensation system is presented.

TUPD74

The Bunch by Bunch Feedback System in J-PARC Main Ring

482

Y. Kurimoto, Y.H. Chin, T. Obina, M. Tobiyama, T. Toyama
KEK, Ibaraki, Japan
Y. Shobuda
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

We report the current status of the bunch by bunch feedback system for the J-PARC Main Ring. The J-PARC Main Ring is the synchrotron accelerating protons from 3 GeV to 30 GeV. It is normally operating at the intensity of 135 kW. The bunch by bunch feedback system have been developed and used for the normal operation of J-PARC Main Ring. The system aims to reduce the coherent transverse oscillation due to the instabilities or injection errors. It consists of a beam position monitor, a stripline kicker and a signal processing electronics. We've observed the injection error leading to the head-tail oscillation and succeed in damping such kind of oscillations and reducing the beam loss significantly.

Poster TUPD74 [1.107 MB]

Paper	Title	Page
TUPD03	Beam Profile Measurement during Top-up Injection with a Pulsed Sextupole Magnet	305
	R. Takai, K. Harada, T. Honda, Y. Kobayashi, S. Nagahashi, N. Nakamura, T. Obina, A. Ueda KEK, Ibaraki, Japan H. Takaki ISSP/SRL, Chiba, Japan
	A beam injection scheme using a pulsed multipole magnet is suitable for the top-up injection because a disturbance to the stored beam is much smaller than that of the conventional scheme using several kicker magnets. At the Photon Factory storage ring, the top-up injection with a pulsed sextupole magnet (PSM) has been used for the user operation since January 2011. In order to ascertain the effect of the PSM injection, we measured turn-by-turn stored beam profiles following the injection kick by using a fast-gated camera. As a result, it was demonstrated that the PSM injection dramatically decreases not only the coherent dipole oscillation but also the beam profile modulation, as expected from the beam tracking simulation.

TUPD73	Fast Orbit Stabilization System for Tandem APPLE-II Undulators at the KEK-PF	479
	T. Obina, K. Harada, R. Takai KEK, Ibaraki, Japan
	A rapid-polarization switching source has been developed in the KEK-PF 2.5-GeV electron storage ring. The source consists of two tandem APPLE-II type elliptically polarizing undulators (EPU) and five fast kicker magnets. The kicker magnets produce a local bump orbit at the frequency up to 100 Hz. Amplitude and phase of these magnets must be tuned precisely in order to minimize the leakage of residual orbit outside of the kicker bump. A fast orbit stabilization system which consists of ADC/FPGA/DAC are also developed to reduce the remaining orbit fluctuations in vertical and horizontal planes. In this paper, design and the preliminary result of the fast orbit compensation system is presented.

TUPD74	The Bunch by Bunch Feedback System in J-PARC Main Ring	482
	Y. Kurimoto, Y.H. Chin, T. Obina, M. Tobiyama, T. Toyama KEK, Ibaraki, Japan Y. Shobuda JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	We report the current status of the bunch by bunch feedback system for the J-PARC Main Ring. The J-PARC Main Ring is the synchrotron accelerating protons from 3 GeV to 30 GeV. It is normally operating at the intensity of 135 kW. The bunch by bunch feedback system have been developed and used for the normal operation of J-PARC Main Ring. The system aims to reduce the coherent transverse oscillation due to the instabilities or injection errors. It consists of a beam position monitor, a stripline kicker and a signal processing electronics. We've observed the injection error leading to the head-tail oscillation and succeed in damping such kind of oscillations and reducing the beam loss significantly.
	Poster TUPD74 [1.107 MB]