ICALEPCS2013 - List of Authors (Miyahara, F.)

Paper

Title

Page

Upgrade of BPM DAQ System for SuperKEKB Injector Linac

1153

M. Satoh, K. Furukawa, F. Miyahara, T. Suwada
KEK, Ibaraki, Japan
T. Kudou, S. Kusano
Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan

The non-destructive beam position monitor (BPM) is indispensable diagnostic tool for the stable beam operation. In the KEK Linac, approximately nineteen BPMs with the strip-line type electrodes are used for the beam orbit measurement and feedback. In addition, some of them are also used for the beam energy feedback loops. The current data acquisition (DAQ) system consists of the fast digital oscilloscopes. A signal from each electrode is analyzed with a predetermined response function up to 50 Hz. In the present DAQ system, the measurement precision of beam position is limited to around 0.5 mm because of ADC resolution. Towards SuperKEKB project, we have a plan to upgrade the BPM DAQ system since the Linac should provide the smaller emittance beam in comparison with previous KEKB Linac. We will report the system description of the new DAQ system and the results of performance test in detail.

THCOCA04

Upgrade of Event Timing System at SuperKEKB

1453

H. Kaji, K. Furukawa, M. Iwasaki, E. Kikutani, T. Kobayashi, F. Miyahara, T.T. Nakamura, M. Suetake, M. Tobiyama
KEK, Ibaraki, Japan
T. Kudo, S. Kusano
Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan
T. Okazaki
EJIT, Hitachi, Ibaraki, Japan

The timing system of the KEKB accelerator will be upgraded for the SuperKEKB project. One of difficulties at SuperKEKB is the positron injection. It takes more than 40ms since positron pulse must be stored at newly constructed damping ring for at least 40ms. Timings of whole accelerators are precisely synchronized for such a long period. We must manage highly frequent injections even with this situation. Typically beam pulse is delivered to one of rings at every 20ms. Besides, the new system must have a capability of realtime selection of injection RF-bucket - we call it "Bucket Selection" at KEKB - for equalizing bunch current at main rings. Bucket Selection also will be upgraded to synchronize buckets of damping ring and those of main rings. This includes the expansion of maximum delay time up to 2ms and the pulse-by-pulse shift of RF phase at 2nd half of injection Linac. We plan to upgrade the Event Timing System from "2-layer type", which simply connect one generator and one receiver, to "cascade type" for satisfying the new injection requirements. We report the basic design of the new timing system and recent studies about key elements of Event Timing System instruments.

Slides THCOCA04 [1.559 MB]

FRCOBAB04

Beam Feedback System Challenges at SuperKEKB Injector Linac

1497

K. Furukawa, R. Ichimiya, M. Iwasaki, H. Kaji, F. Miyahara, T.T. Nakamura, M. Satoh, T. Suwada
KEK, Ibaraki, Japan

SuperKEKB electron/positron asymmetric collider is under construction in order to elucidate new physics beyond the standard model of elementary particle physics. This will be only possible by a precise measurement with 40-times higher luminosity compared with that of KEKB. The injector linac should be upgraded to enable a 20-times smaller beam size of 50 nm at the collision point and twice-larger stored beam current with short lifetime of 10 minutes. At the same time two light source rings, PF and PF-AR, should be filled in top-up injection mode. To this end the linac should be operated with precise beam controls. Dual-layer controls with EPICS and MRF event systems are being enhanced to support precise pulse-to-pulse beam modulation (PPM) at 50Hz. A virtual accelerator (VA) concept is introduced to enable a single linac behaving as four VAs switched by PPM, where each VA corresponds to one of four top-up injections into storage rings. Each VA should be accompanied with independent beam orbit and energy feedback loops to maintain the required beam qualities. The requirements from SuperKEKB HER and LER for beam emittance, energy-spread, and charge are especially challenging.

Slides FRCOBAB04 [1.596 MB]

Paper	Title	Page
THPPC033	Upgrade of BPM DAQ System for SuperKEKB Injector Linac	1153
	M. Satoh, K. Furukawa, F. Miyahara, T. Suwada KEK, Ibaraki, Japan T. Kudou, S. Kusano Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan
	The non-destructive beam position monitor (BPM) is indispensable diagnostic tool for the stable beam operation. In the KEK Linac, approximately nineteen BPMs with the strip-line type electrodes are used for the beam orbit measurement and feedback. In addition, some of them are also used for the beam energy feedback loops. The current data acquisition (DAQ) system consists of the fast digital oscilloscopes. A signal from each electrode is analyzed with a predetermined response function up to 50 Hz. In the present DAQ system, the measurement precision of beam position is limited to around 0.5 mm because of ADC resolution. Towards SuperKEKB project, we have a plan to upgrade the BPM DAQ system since the Linac should provide the smaller emittance beam in comparison with previous KEKB Linac. We will report the system description of the new DAQ system and the results of performance test in detail.

THCOCA04	Upgrade of Event Timing System at SuperKEKB	1453
	H. Kaji, K. Furukawa, M. Iwasaki, E. Kikutani, T. Kobayashi, F. Miyahara, T.T. Nakamura, M. Suetake, M. Tobiyama KEK, Ibaraki, Japan T. Kudo, S. Kusano Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan T. Okazaki EJIT, Hitachi, Ibaraki, Japan
	The timing system of the KEKB accelerator will be upgraded for the SuperKEKB project. One of difficulties at SuperKEKB is the positron injection. It takes more than 40ms since positron pulse must be stored at newly constructed damping ring for at least 40ms. Timings of whole accelerators are precisely synchronized for such a long period. We must manage highly frequent injections even with this situation. Typically beam pulse is delivered to one of rings at every 20ms. Besides, the new system must have a capability of realtime selection of injection RF-bucket - we call it "Bucket Selection" at KEKB - for equalizing bunch current at main rings. Bucket Selection also will be upgraded to synchronize buckets of damping ring and those of main rings. This includes the expansion of maximum delay time up to 2ms and the pulse-by-pulse shift of RF phase at 2nd half of injection Linac. We plan to upgrade the Event Timing System from "2-layer type", which simply connect one generator and one receiver, to "cascade type" for satisfying the new injection requirements. We report the basic design of the new timing system and recent studies about key elements of Event Timing System instruments.
	Slides THCOCA04 [1.559 MB]

FRCOBAB04	Beam Feedback System Challenges at SuperKEKB Injector Linac	1497
	K. Furukawa, R. Ichimiya, M. Iwasaki, H. Kaji, F. Miyahara, T.T. Nakamura, M. Satoh, T. Suwada KEK, Ibaraki, Japan
	SuperKEKB electron/positron asymmetric collider is under construction in order to elucidate new physics beyond the standard model of elementary particle physics. This will be only possible by a precise measurement with 40-times higher luminosity compared with that of KEKB. The injector linac should be upgraded to enable a 20-times smaller beam size of 50 nm at the collision point and twice-larger stored beam current with short lifetime of 10 minutes. At the same time two light source rings, PF and PF-AR, should be filled in top-up injection mode. To this end the linac should be operated with precise beam controls. Dual-layer controls with EPICS and MRF event systems are being enhanced to support precise pulse-to-pulse beam modulation (PPM) at 50Hz. A virtual accelerator (VA) concept is introduced to enable a single linac behaving as four VAs switched by PPM, where each VA corresponds to one of four top-up injections into storage rings. Each VA should be accompanied with independent beam orbit and energy feedback loops to maintain the required beam qualities. The requirements from SuperKEKB HER and LER for beam emittance, energy-spread, and charge are especially challenging.
	Slides FRCOBAB04 [1.596 MB]