IBIC2013 - List of Keywords (kicker)

Paper	Title	Other Keywords	Page
MOPC26	Optimization of Bunch-to-Bunch Isolation in Instability Feedback Systems	coupling, feedback, pick-up, FIR	116
	D. Teytelman Private Address, San Jose, USA
	Bunch-by-bunch feedback formalism is a powerful tool for combating coupled-bunch instabilities in circular accelerators. Imperfections in the analog front and back ends lead to coupling between neighboring bunches. Such coupling limits system performance in both feedback and diagnostic capacities. In this paper, techniques for optimizing bunch-to-bunch isolation within the system will be presented. A new method for improving the performance of the existing systems will be described. The novel approach uses a "shaper" filter in the digital signal processor to compensate for the imperfect response of the power amplifier and kicker combination. An objective optimization method to derive the optimal back end configuration will be presented and illustrated with measurements from several accelerators.
	Poster MOPC26 [0.851 MB]

MOPF26	New Booster Tune Measurement System for TLS and TPS Prototype	booster, synchrotron, BPM, beam-losses	271
	P.C. Chiu, J. Chen, Y.-S. Cheng, K.T. Hsu, S.Y. Hsu, K.H. Hu, C.H. Kuo NSRRC, Hsinchu, Taiwan
	Taiwan Light Source (TLS) is a 1.5 GeV synchrotron based light source and its booster synchrotron was delivered in 1992. Initial booster tune measurement which adopted extraction kicker as beam excitation and use digital oscillator to extract tune was obsolete. Recently, the beam excitation device has been modified to provide more effective excitation strength and new BPM electronics is adopted to acquire tune for routine booster tune measurement. It also provides a chance to experience for the TPS project booster prototype with the similar infrastructure. Efforts will be summarized in the report.

TUBL2	A 4 GS/s Feedback Processing System for Control of Intra-Bunch Instabilities	feedback, SPS, controls, injection	323
	J.D. Fox, J.M. Cesaratto, J.E. Dusatko, J.J. Olsen, K.M. Pollock, C.H. Rivetta, O. Turgut SLAC, Menlo Park, California, USA W. Höfle CERN, Geneva, Switzerland
	Funding: Work supported by the U.S. Department of Energy under contract DE-AC02-76SF00515 and the US LHC Accelerator Research program ( LARP) We present the architecture and implementation overview of a digital signal processing system developed to study control of Electron-Cloud and Transverse Mode coupling instabilities in the CERN SPS. The system is based on a reconfigurable processing architecture which samples vertical bunch motion and applies correction signals at a 4 GS/s rate, allowing 16 samples across a single 5 ns SPS RF bucket. The system requires wideband beam pickups and a vertical kicker structure with GHz bandwidth. This demonstration system implements a general purpose 16 tap FIR control filter for each sample. We present results from SPS machine studies showing the impact of wideband feedback to excite/damp internal modes of vertical motion as well as stabilize an unstable beam. These results highlight the challenges of intra-bunch feedback and show proof of principle feasibility of the architecture.
	Slides TUBL2 [12.154 MB]

TUPC08	Design and Impedance Optimization of the LNLS-UVX Longitudinal Kicker Cavity	longitudinal, impedance, feedback, synchrotron	369
	L. Sanfelici, H.O.C. Duarte, S.R. Marques LNLS, Campinas, Brazil
	Performance evolution of parameters achieved during the electromagnetic design of the longitudinal kicker cavity for the LNLS UVX storage ring is presented. The effort on the electromagnetic optimization process of the heavily loaded cavity has been made to reach the required electrodynamic parameters of the kicker. The results for three different geometries are compared and a good compromise between the longitudinal shunt impedance and the effect of the longitudinal Higher Order Modes (HOM’s) on beam stability has been found.
	Poster TUPC08 [1.365 MB]

TUPC16	Bunch-by-Bunch Feedback and Diagnostics at BESSY II	feedback, longitudinal, beam-losses, injection	399
	A. Schälicke, F. Falkenstern, R. Müller HZB, Berlin, Germany
	At the light source BESSY II new digital bunch-by-bunch feedback systems have been put into operation in January 2013, replacing the existing analog as well as the obsolete digital systems. From the first days of operation the new system successfully suppresses transverse and longitudinal beam instabilities in wide range of machine parameters. The system offers also many new diagnostics opportunities, these include the analysis of instability modes, measurement of the feedback loop gain, and determination of the transfer function. A method to systematically optimise the output amplifier response function with the help of shaper coefficients for the optimal bunch separation has been developed. In addition the analysis of the input data stream allows a passive determination of machine properties like betatron and synchrotron frequencies as well as the longitudinal phases for every bunch. The integration of external triggers permits the analysis of postmortem data, the characterisation of beam-loss events, and monitoring of the injection process. In this contribution first operational experience, the developed data analysis techniques and experimental data will be presented.
	Poster TUPC16 [56.767 MB]

TUPC18	Development of a Highly Efficient Energy Kicker for Longitudinal Bunch-by-Bunch Feedback	longitudinal, synchrotron, electron, storage-ring	407
	M. Masaki, T. Fujita, K. Kobayashi, T. Nakamura, H. Ohkuma, M. Oishi, S. Sasaki, M. Shoji JASRI/SPring-8, Hyogo-ken, Japan
	A highly efficient energy kicker has been developed for longitudinal bunch-by-bunch feedback to suppress synchrotron oscillation of a high-current single electron bunch, and to cure possible longitudinal multi-bunch instability if lower beam energy is to be adopted for emittance reduction and electric power saving in a future upgrade plan of SPring-8. Through the performance test using a prototype kicker, a new water-cooled copper kicker was designed and fabricated, and it has been installed in the storage ring. The new kicker consists of three cells with each cavity length of 96 mm, its resonant frequency of 1.65 GHz, which is 3.25 times of RF frequency of the storage ring, and low Q-factor of 4.2. In beam kick test, the synchrotron oscillation amplitude of 0.64 ps was excited by kick voltage with continuous amplitude modulation at synchrotron frequency when the RF input power was 132 W/3cells. The kick voltage evaluated from the experimental result is 920 V/3cells. Shunt impedance of each kicker cell is estimated as 1.1 kΩ. As we intended, the shunt impedance per length is about three times higher than those of widely used waveguide overloaded cavity type kickers.
	Poster TUPC18 [9.117 MB]

TUPC28	Strip Line Monitor design for the ISIS Proton Synchrotron using the FEA program HFSS	coupling, impedance, feedback, scattering	435
	S.J. Payne STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	This paper reports the development of a strip line monitor for the ISIS accelerator main ring. The strip line is still in the design phase and the work reported here is the results of the FEA programme HFSS. The strip line will eventually form part of a beam instability feedback system and will be used to control instabilities both in the current ISIS machine and for all future ISIS upgrades where higher intensities and energies could be realised. The strip line consists of two pairs of 550mm by 160mm broad flat electrodes configured to allow damping in both the horizontal and vertical planes. The paper describes the efforts to achieve a bandwidth of >260MHz which will allow the feedback system deal with instabilities such as those caused by electron clouds. Design of the electrodes including matching of the feed throughs to the electrodes , concerns of materials for the electrode supports are considered. Also considered are methods used to improved inter-electrode decoupling (to better than -30db) . Results in the form of scattering parameters, smith charts, time domain reflectivity and shunt impedances will be presented.

TUPC36	First Realization and Performance Study of a Single-Shot Longitudinal Bunch Profile Monitor Utilizing a Transverse Deflecting Structure	longitudinal, FEL, feedback, electron	456
	M. Yan, C. Behrens, C. Gerth, R. Kammering, A. Langner, F. Obier, V. Rybnikov DESY, Hamburg, Germany J. Wychowaniak TUL-DMCS, Łódź, Poland
	For the control and optimization of electron beam parameters at modern free-electron lasers (FEL), transverse deflecting structures (TDS) in combination with imaging screens have been widely used as robust longitudinal diagnostics with single-shot capability, high resolution and large dynamic range. At the free-electron laser in Hamburg (FLASH), a longitudinal bunch profile monitor utilizing a TDS has been realized. In combined use with a fast kicker magnet and an off-axis imaging screen, selection and measurement of a single bunch out of the bunch train with bunch spacing down to 1us can be achieved without affecting the remaining bunches which continue to generate FEL radiation during user operation. Technical obstacles have been overcome such as suppression of coherent transition radiation from the imaging screen, the continuous image acquisition and processing with the bunch train repetition rate of 10Hz. The monitor, which provides the longitudinal bunch profile and length, has been used routinely at FLASH. In this paper, we present the setup and operation of the longitudinal bunch profile monitor as well as the performance during user operation.

WEBL2	Applications of Stripline and Cavity Beam Position Monitors in Low-Latency, High-Precision, Intra-Train Feedback Systems	feedback, BPM, beam-position, extraction	630
	M.R. Davis, D.R. Bett, N. Blaskovic Kraljevic, P. Burrows, G.B. Christian, Y.I. Kim, C. Perry JAI, Oxford, United Kingdom
	Two, low-latency, sub-micron beam position monitoring (BPM) systems have been developed and tested with beam at the KEK Accelerator Test Facility (ATF2). One system (‘upstream’), based on stripline BPMs uses fast analogue front-end signal processing and has demonstrated a position resolution as low as 400nm for beam intensities of ~1 nC, with single-pass beam. The other (‘IP’) system, based on low-Q cavity BPMs and utilising custom signal processing electronics designed for low latency, provides a single pass resolution of approximately 100nm. The BPM position data are digitised by fast ADCs on a custom FPGA-based feedback controller and used in three modes: 1) the upstream BPM data are used to drive a pair of local kickers nominally orthogonal in phase in closed-loop feedback mode; 2) the upstream BPM data are used to drive a downstream kicker in the ATF2 final focus region in feedforward mode; 3) the IP cavity BPM data are used to drive a local downstream kicker in the ATF2 final focus region in closed-loop feedback mode. In each case the beam jitter is measured downstream of the final focus system with the IP cavity BPMs. The relative performance of these systems is compared.
	Slides WEBL2 [1.934 MB]

WEPC28	Bunch By Bunch Transverse Beam Position Observation and Analyze During Injection at SSRF	injection, transverse, betatron, storage-ring	746
	Y.B. Leng, Y.B. Yan, Y. Yang, R.X. Yuan, N. Zhang SSRF, Shanghai, People's Republic of China
	Funding: Work supported by National Science Foundation of China (No. 11075198) Top-up operation has been performed at SSRF since Dec. 2012. Orbit disturbance every 10 minutes decreased the quality of synchrotron radiation. In order to minimize this disturbance the tilts and the timing of injection kickers need to be tuning carefully based on real beam information. A set of button type pick-up and a scope based IOC were employed to capture the transient beam movement with bunch by bunch rate during injection. Several sets of observation and analyze will be discussed in this paper.

WEPC39	First Tests of the Top-up Gating at Synchrotron SOLEIL	injection, SOLEIL, synchrotron, storage-ring	775
	J.P. Ricaud, L. Cassinari, P. Dumas, P. Lebasque, A. Nadji SOLEIL, Gif-sur-Yvette, France
	Since 2006, Synchrotron SOLEIL is delivering photons to its beamlines. Until 2012, thanks to the excellent performances of the injection system of the storage ring, the perturbation on the position of the stored beam was small enough to be accepted by the users. For some specific experiments, few beamlines expressed their wish to be able to stop their data acquisition during the injection. To fulfill this need, the diagnostics group of Synchrotron SOLEIL has designed the “TimEX3” board which was integrated into the timing system allowing the gating of the Top-up injection. This design was released as open hardware. Towards this aim, we decided to design it with the open source and free EDA software “KiCad”, and to make it available under the CERN’s Open Hardware Repository.
	Poster WEPC39 [0.521 MB]

Paper

Title

Other Keywords

Page

MOPC26

Optimization of Bunch-to-Bunch Isolation in Instability Feedback Systems

coupling, feedback, pick-up, FIR

116

D. Teytelman
Private Address, San Jose, USA

Bunch-by-bunch feedback formalism is a powerful tool for combating coupled-bunch instabilities in circular accelerators. Imperfections in the analog front and back ends lead to coupling between neighboring bunches. Such coupling limits system performance in both feedback and diagnostic capacities. In this paper, techniques for optimizing bunch-to-bunch isolation within the system will be presented. A new method for improving the performance of the existing systems will be described. The novel approach uses a "shaper" filter in the digital signal processor to compensate for the imperfect response of the power amplifier and kicker combination. An objective optimization method to derive the optimal back end configuration will be presented and illustrated with measurements from several accelerators.

Poster MOPC26 [0.851 MB]

MOPF26

New Booster Tune Measurement System for TLS and TPS Prototype

booster, synchrotron, BPM, beam-losses

271

P.C. Chiu, J. Chen, Y.-S. Cheng, K.T. Hsu, S.Y. Hsu, K.H. Hu, C.H. Kuo
NSRRC, Hsinchu, Taiwan

Taiwan Light Source (TLS) is a 1.5 GeV synchrotron based light source and its booster synchrotron was delivered in 1992. Initial booster tune measurement which adopted extraction kicker as beam excitation and use digital oscillator to extract tune was obsolete. Recently, the beam excitation device has been modified to provide more effective excitation strength and new BPM electronics is adopted to acquire tune for routine booster tune measurement. It also provides a chance to experience for the TPS project booster prototype with the similar infrastructure. Efforts will be summarized in the report.

TUBL2

A 4 GS/s Feedback Processing System for Control of Intra-Bunch Instabilities

feedback, SPS, controls, injection

323

J.D. Fox, J.M. Cesaratto, J.E. Dusatko, J.J. Olsen, K.M. Pollock, C.H. Rivetta, O. Turgut
SLAC, Menlo Park, California, USA
W. Höfle
CERN, Geneva, Switzerland

Funding: Work supported by the U.S. Department of Energy under contract DE-AC02-76SF00515 and the US LHC Accelerator Research program ( LARP)
We present the architecture and implementation overview of a digital signal processing system developed to study control of Electron-Cloud and Transverse Mode coupling instabilities in the CERN SPS. The system is based on a reconfigurable processing architecture which samples vertical bunch motion and applies correction signals at a 4 GS/s rate, allowing 16 samples across a single 5 ns SPS RF bucket. The system requires wideband beam pickups and a vertical kicker structure with GHz bandwidth. This demonstration system implements a general purpose 16 tap FIR control filter for each sample. We present results from SPS machine studies showing the impact of wideband feedback to excite/damp internal modes of vertical motion as well as stabilize an unstable beam. These results highlight the challenges of intra-bunch feedback and show proof of principle feasibility of the architecture.

Slides TUBL2 [12.154 MB]

TUPC08

Design and Impedance Optimization of the LNLS-UVX Longitudinal Kicker Cavity

longitudinal, impedance, feedback, synchrotron

369

L. Sanfelici, H.O.C. Duarte, S.R. Marques
LNLS, Campinas, Brazil

Performance evolution of parameters achieved during the electromagnetic design of the longitudinal kicker cavity for the LNLS UVX storage ring is presented. The effort on the electromagnetic optimization process of the heavily loaded cavity has been made to reach the required electrodynamic parameters of the kicker. The results for three different geometries are compared and a good compromise between the longitudinal shunt impedance and the effect of the longitudinal Higher Order Modes (HOM’s) on beam stability has been found.

Poster TUPC08 [1.365 MB]

TUPC16

Bunch-by-Bunch Feedback and Diagnostics at BESSY II

feedback, longitudinal, beam-losses, injection

399

A. Schälicke, F. Falkenstern, R. Müller
HZB, Berlin, Germany

At the light source BESSY II new digital bunch-by-bunch feedback systems have been put into operation in January 2013, replacing the existing analog as well as the obsolete digital systems. From the first days of operation the new system successfully suppresses transverse and longitudinal beam instabilities in wide range of machine parameters. The system offers also many new diagnostics opportunities, these include the analysis of instability modes, measurement of the feedback loop gain, and determination of the transfer function. A method to systematically optimise the output amplifier response function with the help of shaper coefficients for the optimal bunch separation has been developed. In addition the analysis of the input data stream allows a passive determination of machine properties like betatron and synchrotron frequencies as well as the longitudinal phases for every bunch. The integration of external triggers permits the analysis of postmortem data, the characterisation of beam-loss events, and monitoring of the injection process. In this contribution first operational experience, the developed data analysis techniques and experimental data will be presented.

Poster TUPC16 [56.767 MB]

TUPC18

Development of a Highly Efficient Energy Kicker for Longitudinal Bunch-by-Bunch Feedback

longitudinal, synchrotron, electron, storage-ring

407

M. Masaki, T. Fujita, K. Kobayashi, T. Nakamura, H. Ohkuma, M. Oishi, S. Sasaki, M. Shoji
JASRI/SPring-8, Hyogo-ken, Japan

A highly efficient energy kicker has been developed for longitudinal bunch-by-bunch feedback to suppress synchrotron oscillation of a high-current single electron bunch, and to cure possible longitudinal multi-bunch instability if lower beam energy is to be adopted for emittance reduction and electric power saving in a future upgrade plan of SPring-8. Through the performance test using a prototype kicker, a new water-cooled copper kicker was designed and fabricated, and it has been installed in the storage ring. The new kicker consists of three cells with each cavity length of 96 mm, its resonant frequency of 1.65 GHz, which is 3.25 times of RF frequency of the storage ring, and low Q-factor of 4.2. In beam kick test, the synchrotron oscillation amplitude of 0.64 ps was excited by kick voltage with continuous amplitude modulation at synchrotron frequency when the RF input power was 132 W/3cells. The kick voltage evaluated from the experimental result is 920 V/3cells. Shunt impedance of each kicker cell is estimated as 1.1 kΩ. As we intended, the shunt impedance per length is about three times higher than those of widely used waveguide overloaded cavity type kickers.

Poster TUPC18 [9.117 MB]

TUPC28

Strip Line Monitor design for the ISIS Proton Synchrotron using the FEA program HFSS

coupling, impedance, feedback, scattering

435

S.J. Payne
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

This paper reports the development of a strip line monitor for the ISIS accelerator main ring. The strip line is still in the design phase and the work reported here is the results of the FEA programme HFSS. The strip line will eventually form part of a beam instability feedback system and will be used to control instabilities both in the current ISIS machine and for all future ISIS upgrades where higher intensities and energies could be realised. The strip line consists of two pairs of 550mm by 160mm broad flat electrodes configured to allow damping in both the horizontal and vertical planes. The paper describes the efforts to achieve a bandwidth of >260MHz which will allow the feedback system deal with instabilities such as those caused by electron clouds. Design of the electrodes including matching of the feed throughs to the electrodes , concerns of materials for the electrode supports are considered. Also considered are methods used to improved inter-electrode decoupling (to better than -30db) . Results in the form of scattering parameters, smith charts, time domain reflectivity and shunt impedances will be presented.

TUPC36

First Realization and Performance Study of a Single-Shot Longitudinal Bunch Profile Monitor Utilizing a Transverse Deflecting Structure

longitudinal, FEL, feedback, electron

456

M. Yan, C. Behrens, C. Gerth, R. Kammering, A. Langner, F. Obier, V. Rybnikov
DESY, Hamburg, Germany
J. Wychowaniak
TUL-DMCS, Łódź, Poland

For the control and optimization of electron beam parameters at modern free-electron lasers (FEL), transverse deflecting structures (TDS) in combination with imaging screens have been widely used as robust longitudinal diagnostics with single-shot capability, high resolution and large dynamic range. At the free-electron laser in Hamburg (FLASH), a longitudinal bunch profile monitor utilizing a TDS has been realized. In combined use with a fast kicker magnet and an off-axis imaging screen, selection and measurement of a single bunch out of the bunch train with bunch spacing down to 1us can be achieved without affecting the remaining bunches which continue to generate FEL radiation during user operation. Technical obstacles have been overcome such as suppression of coherent transition radiation from the imaging screen, the continuous image acquisition and processing with the bunch train repetition rate of 10Hz. The monitor, which provides the longitudinal bunch profile and length, has been used routinely at FLASH. In this paper, we present the setup and operation of the longitudinal bunch profile monitor as well as the performance during user operation.

WEBL2

Applications of Stripline and Cavity Beam Position Monitors in Low-Latency, High-Precision, Intra-Train Feedback Systems

feedback, BPM, beam-position, extraction

630

M.R. Davis, D.R. Bett, N. Blaskovic Kraljevic, P. Burrows, G.B. Christian, Y.I. Kim, C. Perry
JAI, Oxford, United Kingdom

Two, low-latency, sub-micron beam position monitoring (BPM) systems have been developed and tested with beam at the KEK Accelerator Test Facility (ATF2). One system (‘upstream’), based on stripline BPMs uses fast analogue front-end signal processing and has demonstrated a position resolution as low as 400nm for beam intensities of ~1 nC, with single-pass beam. The other (‘IP’) system, based on low-Q cavity BPMs and utilising custom signal processing electronics designed for low latency, provides a single pass resolution of approximately 100nm. The BPM position data are digitised by fast ADCs on a custom FPGA-based feedback controller and used in three modes: 1) the upstream BPM data are used to drive a pair of local kickers nominally orthogonal in phase in closed-loop feedback mode; 2) the upstream BPM data are used to drive a downstream kicker in the ATF2 final focus region in feedforward mode; 3) the IP cavity BPM data are used to drive a local downstream kicker in the ATF2 final focus region in closed-loop feedback mode. In each case the beam jitter is measured downstream of the final focus system with the IP cavity BPMs. The relative performance of these systems is compared.

Slides WEBL2 [1.934 MB]

WEPC28

Bunch By Bunch Transverse Beam Position Observation and Analyze During Injection at SSRF

injection, transverse, betatron, storage-ring

746

Y.B. Leng, Y.B. Yan, Y. Yang, R.X. Yuan, N. Zhang
SSRF, Shanghai, People's Republic of China

Funding: Work supported by National Science Foundation of China (No. 11075198)
Top-up operation has been performed at SSRF since Dec. 2012. Orbit disturbance every 10 minutes decreased the quality of synchrotron radiation. In order to minimize this disturbance the tilts and the timing of injection kickers need to be tuning carefully based on real beam information. A set of button type pick-up and a scope based IOC were employed to capture the transient beam movement with bunch by bunch rate during injection. Several sets of observation and analyze will be discussed in this paper.

WEPC39

First Tests of the Top-up Gating at Synchrotron SOLEIL

injection, SOLEIL, synchrotron, storage-ring

775

J.P. Ricaud, L. Cassinari, P. Dumas, P. Lebasque, A. Nadji
SOLEIL, Gif-sur-Yvette, France

Since 2006, Synchrotron SOLEIL is delivering photons to its beamlines. Until 2012, thanks to the excellent performances of the injection system of the storage ring, the perturbation on the position of the stored beam was small enough to be accepted by the users. For some specific experiments, few beamlines expressed their wish to be able to stop their data acquisition during the injection. To fulfill this need, the diagnostics group of Synchrotron SOLEIL has designed the “TimEX3” board which was integrated into the timing system allowing the gating of the Top-up injection. This design was released as open hardware. Towards this aim, we decided to design it with the open source and free EDA software “KiCad”, and to make it available under the CERN’s Open Hardware Repository.

Poster WEPC39 [0.521 MB]