IBIC2012 - List of Authors (Flanagan, J.W.)

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.

MOPB72

First Measurements with Coded Aperture X-ray Monitor at the ATF2 Extraction Line

237

J.W. Flanagan, A. Arinaga, H. Fukuma, H. Ikeda, T.M. Mitsuhashi
KEK, Ibaraki, Japan
G.S. Varner
University of Hawaii, Honolulu, HI, USA

Funding: Kakenhi
The ATF2 extraction line is used as a test-bed for technologies needed for the ILC final-focus region. An x-ray extraction beam line has been constructed at the final upstream bend before the extraction line straight section, for development and testing of optics and readout systems for a coded aperture-based imaging system. The x-ray monitor is expected to eventually be able to measure single-shot vertical bunch sizes down to a few microns in size at its source location in the ATF2 extraction line. Preliminary scanned measurements have been made with beams in the ~15 micron range, and it is planned to make more measurements with further-tuned beam, and with fast read-out electronics. The details of the layout, expected performance, and preliminary measurement results will be presented.

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.

TUPB74

Diamond Mirrors for the SuperKEKB Synchtron Radiation Monitor

515

J.W. Flanagan, A. Arinaga, H. Fukuma, H. Ikeda
KEK, Ibaraki, Japan

The SuperKEKB accelerator, a 40x luminosity upgrade to the KEKB accelerator, will be a high-current, low-emittance double ring collider. The beryllium primary extraction mirrors used for the synchrotron radiation monitors at KEKB suffered from heat distortion due to incident synchrotron radiation, leading to systematic changes in magnification with beam current and necessitating continuous monitoring and compensation of such distortions in order to correctly measure the beam sizes. The heat loads on the extraction mirrors will be higher at SuperKEKB, with heat-induced magnification changes up to 40% expected if the same mirrors were used as at KEKB. We are working on a design based on mirrors made of quasi-monocrystalline diamond, which has much higher heat conductance and a lower thermal expansion coefficient than beryllium. With such mirrors it is targeted to reduce the beam current-dependent magnification effects to the level of a few percent at SuperKEKB. Measurements of heat-induced deformations on fabricated prototype mirrors will be presented, along with comparisons with the results of numerical simulations.

WECD01

Operation of a Single Pass, Bunch-by-bunch x-ray Beam Size Monitor for the CESR Test Accelerator Research Program

585

N.T. Rider, M.G. Billing, M. P. Ehrlichman, M.A. Palmer, D.P. Peterson, D. L. Rubin, J.P. Shanks, K.G. Sonnad
CLASSE, Ithaca, New York, USA
J.W. Flanagan
KEK, Ibaraki, Japan

Funding: This work is supported by the US National Science Foundation PHY-0734867, PHY-1002467, and the US Department of Energy DE-FC02-08ER41538, DE-SC0006505.
The CESR Test Accelerator (CesrTA) program targets the study of beam physics issues relevant to linear collider damping rings and other low emittance storage rings. This endeavor requires new instrumentation to study the beam dynamics along trains of ultra low emittance bunches. A key element of the program has been the design, commissioning and operation of an x-ray beam size monitor capable, on a turn by turn basis, of collecting single pass measurements of each individual bunch in a train over many thousands of turns. This new instrument utilizes custom, high bandwidth amplifiers and digitization hardware and firmware to collect signals from a linear InGaAs diode array. The instrument has been optimized to allow measurements with 3x10⁹ to 1x10¹¹ particles per bunch. This paper reports on the operational capabilities of this instrument, improvements for its performance, and the methods utilized in data analysis. Examples of key measurements which illustrate the instrument's performance are presented. This device demonstrates measurement capabilities applicable to future high energy physics accelerators and light sources.

Slides WECD01 [3.480 MB]

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.

MOPB72	First Measurements with Coded Aperture X-ray Monitor at the ATF2 Extraction Line	237
	J.W. Flanagan, A. Arinaga, H. Fukuma, H. Ikeda, T.M. Mitsuhashi KEK, Ibaraki, Japan G.S. Varner University of Hawaii, Honolulu, HI, USA
	Funding: Kakenhi The ATF2 extraction line is used as a test-bed for technologies needed for the ILC final-focus region. An x-ray extraction beam line has been constructed at the final upstream bend before the extraction line straight section, for development and testing of optics and readout systems for a coded aperture-based imaging system. The x-ray monitor is expected to eventually be able to measure single-shot vertical bunch sizes down to a few microns in size at its source location in the ATF2 extraction line. Preliminary scanned measurements have been made with beams in the ~15 micron range, and it is planned to make more measurements with further-tuned beam, and with fast read-out electronics. The details of the layout, expected performance, and preliminary measurement results will be presented.

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.

TUPB74	Diamond Mirrors for the SuperKEKB Synchtron Radiation Monitor	515
	J.W. Flanagan, A. Arinaga, H. Fukuma, H. Ikeda KEK, Ibaraki, Japan
	The SuperKEKB accelerator, a 40x luminosity upgrade to the KEKB accelerator, will be a high-current, low-emittance double ring collider. The beryllium primary extraction mirrors used for the synchrotron radiation monitors at KEKB suffered from heat distortion due to incident synchrotron radiation, leading to systematic changes in magnification with beam current and necessitating continuous monitoring and compensation of such distortions in order to correctly measure the beam sizes. The heat loads on the extraction mirrors will be higher at SuperKEKB, with heat-induced magnification changes up to 40% expected if the same mirrors were used as at KEKB. We are working on a design based on mirrors made of quasi-monocrystalline diamond, which has much higher heat conductance and a lower thermal expansion coefficient than beryllium. With such mirrors it is targeted to reduce the beam current-dependent magnification effects to the level of a few percent at SuperKEKB. Measurements of heat-induced deformations on fabricated prototype mirrors will be presented, along with comparisons with the results of numerical simulations.

WECD01	Operation of a Single Pass, Bunch-by-bunch x-ray Beam Size Monitor for the CESR Test Accelerator Research Program	585
	N.T. Rider, M.G. Billing, M. P. Ehrlichman, M.A. Palmer, D.P. Peterson, D. L. Rubin, J.P. Shanks, K.G. Sonnad CLASSE, Ithaca, New York, USA J.W. Flanagan KEK, Ibaraki, Japan
	Funding: This work is supported by the US National Science Foundation PHY-0734867, PHY-1002467, and the US Department of Energy DE-FC02-08ER41538, DE-SC0006505. The CESR Test Accelerator (CesrTA) program targets the study of beam physics issues relevant to linear collider damping rings and other low emittance storage rings. This endeavor requires new instrumentation to study the beam dynamics along trains of ultra low emittance bunches. A key element of the program has been the design, commissioning and operation of an x-ray beam size monitor capable, on a turn by turn basis, of collecting single pass measurements of each individual bunch in a train over many thousands of turns. This new instrument utilizes custom, high bandwidth amplifiers and digitization hardware and firmware to collect signals from a linear InGaAs diode array. The instrument has been optimized to allow measurements with 3x10⁹ to 1x10¹¹ particles per bunch. This paper reports on the operational capabilities of this instrument, improvements for its performance, and the methods utilized in data analysis. Examples of key measurements which illustrate the instrument's performance are presented. This device demonstrates measurement capabilities applicable to future high energy physics accelerators and light sources.
	Slides WECD01 [3.480 MB]