IBIC2012 - List of Authors (Tobiyama, M.)

Paper

Title

Page

Beam Instrumentation for the SuperKEKB Rings

6

H. Fukuma, A. Arinaga, J.W. Flanagan, H. Ikeda, H. Ishii, S. Kanaeda, K. Mori, M. Tejima, M. Tobiyama
KEK, Ibaraki, Japan
G. Bonvicini, H. Farhat, R.S. Gillard
Wayne State University, USA
G.S. Varner
University of Hawaii, Honolulu, HI, USA

The electron-positron collider KEKB B-factory is currently being upgraded to SuperKEKB. The design luminosity of 8 x 10³⁵ /cm²/s will be achieved using beams with low emittance of several nm and doubling beam currents to 2.6 A in the electron ring (HER) and 3.6 A in the positron ring (LER). A beam position monitor (BPM) system of HER and LER will be equipped with super-heterodyne detectors, turn by turn log ratio detectors with fast gates to measure optics parameters during collision operation and detectors of BPMs near the collision point (IP) for orbit feedback to maintain stable collision. New X-ray beam profile monitors based on the coded aperture method will be installed aiming at bunch by bunch measurement of the beam profile. A large angle beamstrahlung monitor detecting polarization of the synchrotron radiation generated by beam-beam interaction will be installed near IP to obtain information about the beam-beam geometry. The bunch by bunch feedback system will be upgraded using low noise frontend electronics and new 12 bits iGp digital filters. An overview of beam instrumentation of SuperKEKB rings will be given in this paper.

Slides MOCB01 [8.073 MB]

MOPA36

Development of Bunch Current and Oscillation Recorder for SuperKEKB Accelerator

138

M. Tobiyama, J.W. Flanagan
KEK, Ibaraki, Japan

A High-speed digital signal memory has been developed for the bunch current and oscillation recorder for SuperKEKB. The memory consists of an 8-bit ADC and a FPGA daughter card with Spartan6 and DDR2 memories commercially available on a double width VME card. The block-RAM on the FPGA is used to transfer bunch current data with low latency for prompt bunch current measurements, and the large DDR2 memory is used for long-duration position recording, such as post-mortem bunch oscillation recording. The performance of the board, including data transfer rate, will be presented.

TUTA02

BPM Electrode and High Power Feedthrough - Special Topics in Wideband Feedthrough

297

M. Tobiyama
KEK, Ibaraki, Japan

Since most of the beam in accelerator runs in the vacuum chamber made of metal, it is needed to have 'feedthrough' to get or to put the RF signal from or to beam. For example, we can get the beam signal by using button-type electrode which have electrical isolation material to seal the vacuum. Now, many types of vacuum feedthrough with coaxial structure are available commercially. Nevertheless, it is meaningful to understand the design principle of the feedthough needed for the beam instrumentation, especially for short bunch length, high beam current machine. I will show the design method of the feedthrough such as BPM electrodes or high power feedthroughs using 3D EM-codes such as HFSS or GdfidL based on several examples developed for SuperKEKB accelerators.

Slides TUTA02 [6.806 MB]

TUPB53

Abort Diagnostics and Analysis during KEKB Operation

477

H. Ikeda, J.W. Flanagan, T. Furuya, M. Tobiyama
KEK, Ibaraki, Japan
M. Tanaka
Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan

KEKB has stopped since June 2010 for upgrading the luminosity 40 times, i.e. SuperKEKB. During the operation of 11 years, a pair of controlled beam abort systems worked more than 10000 times to protect the hardware components of KEKB accelerator and the detector against the high intensity beams of LER and HER. Optimization of the abort trigger was necessary to balance efficient operation with the safety of the hardware. Therefore, we analyzed one-by-one all of the aborts, and continually adjusted the abort system. The diagnostic system was based on a high-sampling-rate data logger that recorded beam currents, RF signals and beam loss monitor signals. The beam oscillation signals, vacuum pressure and detector dose rate were also examined. This paper describes the typical abort causes, optimizations of abort levels, and abort statistics over approximately eight years after having arrived at high beam current operation.

Paper	Title	Page
MOCB01	Beam Instrumentation for the SuperKEKB Rings	6
	H. Fukuma, A. Arinaga, J.W. Flanagan, H. Ikeda, H. Ishii, S. Kanaeda, K. Mori, M. Tejima, M. Tobiyama KEK, Ibaraki, Japan G. Bonvicini, H. Farhat, R.S. Gillard Wayne State University, USA G.S. Varner University of Hawaii, Honolulu, HI, USA
	The electron-positron collider KEKB B-factory is currently being upgraded to SuperKEKB. The design luminosity of 8 x 10³⁵ /cm²/s will be achieved using beams with low emittance of several nm and doubling beam currents to 2.6 A in the electron ring (HER) and 3.6 A in the positron ring (LER). A beam position monitor (BPM) system of HER and LER will be equipped with super-heterodyne detectors, turn by turn log ratio detectors with fast gates to measure optics parameters during collision operation and detectors of BPMs near the collision point (IP) for orbit feedback to maintain stable collision. New X-ray beam profile monitors based on the coded aperture method will be installed aiming at bunch by bunch measurement of the beam profile. A large angle beamstrahlung monitor detecting polarization of the synchrotron radiation generated by beam-beam interaction will be installed near IP to obtain information about the beam-beam geometry. The bunch by bunch feedback system will be upgraded using low noise frontend electronics and new 12 bits iGp digital filters. An overview of beam instrumentation of SuperKEKB rings will be given in this paper.
	Slides MOCB01 [8.073 MB]

MOPA36	Development of Bunch Current and Oscillation Recorder for SuperKEKB Accelerator	138
	M. Tobiyama, J.W. Flanagan KEK, Ibaraki, Japan
	A High-speed digital signal memory has been developed for the bunch current and oscillation recorder for SuperKEKB. The memory consists of an 8-bit ADC and a FPGA daughter card with Spartan6 and DDR2 memories commercially available on a double width VME card. The block-RAM on the FPGA is used to transfer bunch current data with low latency for prompt bunch current measurements, and the large DDR2 memory is used for long-duration position recording, such as post-mortem bunch oscillation recording. The performance of the board, including data transfer rate, will be presented.

TUTA02	BPM Electrode and High Power Feedthrough - Special Topics in Wideband Feedthrough	297
	M. Tobiyama KEK, Ibaraki, Japan
	Since most of the beam in accelerator runs in the vacuum chamber made of metal, it is needed to have 'feedthrough' to get or to put the RF signal from or to beam. For example, we can get the beam signal by using button-type electrode which have electrical isolation material to seal the vacuum. Now, many types of vacuum feedthrough with coaxial structure are available commercially. Nevertheless, it is meaningful to understand the design principle of the feedthough needed for the beam instrumentation, especially for short bunch length, high beam current machine. I will show the design method of the feedthrough such as BPM electrodes or high power feedthroughs using 3D EM-codes such as HFSS or GdfidL based on several examples developed for SuperKEKB accelerators.
	Slides TUTA02 [6.806 MB]

TUPB53	Abort Diagnostics and Analysis during KEKB Operation	477
	H. Ikeda, J.W. Flanagan, T. Furuya, M. Tobiyama KEK, Ibaraki, Japan M. Tanaka Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan
	KEKB has stopped since June 2010 for upgrading the luminosity 40 times, i.e. SuperKEKB. During the operation of 11 years, a pair of controlled beam abort systems worked more than 10000 times to protect the hardware components of KEKB accelerator and the detector against the high intensity beams of LER and HER. Optimization of the abort trigger was necessary to balance efficient operation with the safety of the hardware. Therefore, we analyzed one-by-one all of the aborts, and continually adjusted the abort system. The diagnostic system was based on a high-sampling-rate data logger that recorded beam currents, RF signals and beam loss monitor signals. The beam oscillation signals, vacuum pressure and detector dose rate were also examined. This paper describes the typical abort causes, optimizations of abort levels, and abort statistics over approximately eight years after having arrived at high beam current operation.