IPAC2019 - Classification: MC6: Beam Instrumentation, Controls, Feedback and Operational Aspects / T05 Beam Feedback Systems

Paper	Title	Page
THPRB004	Hardware and Firmware Development for Enhanced Orbit Diagnostics at the Australian Synchrotron	3802
	S. Chen, R.B. Hogan, A. Michalczyk, A.C. Starritt, Y.E. Tan AS - ANSTO, Clayton, Australia
	The Enhanced Orbit Diagnostic (EOD) features will be an expansion to the existing Fast Orbit Feedback (FOFB) system that is currently in operation. The new system will add the capability of online cor-rector-to-position response matrix calculation; this will significantly reduce the required measurement time. The new features will allow the injection of PRBS noise or sinusoidal signals into correctors, to characterise and monitor the FOFB system’s parameters and performance and track it over time. The system will be built based on a Xilinx ZYNQ Sys-tem-on-Module (SOM) mounted on an in-house designed motherboard to which the existing FOFB daughter board is plugged into.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB004
About •	paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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THPRB005	Orbit Feedback and Beam Stability at the Australian Synchrotron	3805
	A.C. Starritt, A. Pozar, Y.E. Tan AS - ANSTO, Clayton, Australia
	The Australian Synchrotron (AS) is a 3rd generation light source which has been in operation since 2006. Measurement of the storage ring’s beam position is provided by 98 beam position monitors, and corrections can be applied using 42 horizontal and 56 vertical slow corrector magnets, and 42 horizontal and 42 vertical fast corrector magnets. This paper provides a background describing the feedback strategies adopted at the AS leading to the current integrated orbit feedback system, together with a description of the beam position analyse techniques currently in use. It will also highlight some of the issues encountered with the system and how they were overcome. The paper also describes planned improvements, including the enhanced orbit diagnostics functionality we are intending to introduce in the next 12 months.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB005
About •	paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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THPRB023	An MTCA.4 Based Position Feedback Application Using Laserinterferometers	3853
	K.P. Przygoda, Ł. Butkowski, S. Pfeiffer, H. Schlarb, P. Wiljes DESY, Hamburg, Germany
	To perform experiments on the nanometer scale at high brilliant x-ray light sources, it is highly recommended to have the mechanical components of the experiment, like lenses, mirrors and samples, as stable as possible. Since these components need to move from nanometer up to millimeter range they cannot be stabilized by only using rigid structures. For that reason an active stabilization system with fast and precise sensors needs to be developed. Here a Laserinterferometer is used, which provides picometer resolution at several MHz sample rate. In this paper we will present a laboratory setup which consists of a 6-slot Micro Telecommunication Computing Architecture generation 4 (MTCA.4) crate with standard components such MicroTCA carrier hub (MCH), central processing unit (CPU), power supply (PS) and cooling unit (CU). The Interferometer application has been setup with Deutsches Elektronen-Synchrotron (DESY) advanced mezzanine card (DAMC-FMC20) data processing unit, DESY Field Programmable Gate Array (FPGA) mezzanine card (DFMC-UNIO) universal input and output extension and DESY rear transition module (DRTM-PZT4) piezo driver. The encoder signals given by the interferometer controller are processed within the FPGA and then forwarded to the piezo amplifier RTM-board. The signal processing application includes decoding the digital feedback signal, calculating the coordinate transform for specific experimental setups and closed-loop operation based on a proportional integral derivative (PID) controller. The first results of the laboratory setup are demonstrated and briefly discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB023
About •	paper received ※ 12 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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THPRB037	Improved Frequency Characteristics Using Multiple Stripline Kickers	3893
	T. Toyama, A. Kobayashi, H. Kuboki, M. Okada KEK, Tokai, Ibaraki, Japan
	One of the important ingredient in the intra-bunch transverse feedback is a kicker. The frequency characteristics of the kicker suffers from the transit-time factor, sin(kl)/kl. We examine the frequency characteristics of multiple kickers system. Relation between the excitation patterns of the multiple kickers and the frequency characteristics are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB037
About •	paper received ※ 23 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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THPRB054	Design of a Ultrafast Stripline Kicker for Bunch-by-Bunch Feedback	3931
	J. Wang, P. Li, D. Wu, D.X. Xiao, L.G. Yan CAEP/IAE, Mianyang, Sichuan, People’s Republic of China
	Lorentz force detuning and beam loading effect of the rf cavities will induce a slope of the cavity gradient. Combed with the cavity misalignments, transverse position of subsequent bunches will differ from each other. The CAEP THz Free Electron Laser facility(CTFEL) will have a fast transverse bunch-by-bunch feedback system on its test beamline, which is used to correct the beam position differences of individual bunches in the macro-pulses. The time response of the kicker is rigid for the interval of the micro-pulses is 18.5ns and will upgrade to about 2 ns, requiring impedance matching of the kicker with the power source and transmission system in a high bandwidth. Also, the electromagnetic field must reach the requirements of the beam parameters. In this paper, the structure design and the optimization of the geometric parameters of the ultrafast stripline kicker is presented. The characteristic impedance, transmission characteristics, field consistency are analyzed and optimized. And the feedback signal generation scheme for continuous bunch trains was proposed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB054
About •	paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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THPRB062	New Orbit Correction Method Based on SVDC Algorithm for Ring Based Light Sources	3943
	X.Y. Huang, J.S. Cao, Y.Y. Du, Y.H. Lu, H.Z. Ma, Y.F. Ma, Y.F. Sui, S.J. Wei, Y. Wei, Q. Ye, X.E. Zhang, D.C. Zhu IHEP, Beijing, People’s Republic of China
	Funding: Union Foundation of excellent post-doctoral of China Orbit feedback system is essential for realizing the exceeding beam stability in modern ring based light sources. Most advanced light sources adopt the global correction scheme by using singular value decomposition (SVD) algorithm. In this paper, a new SVD with constraints method (SVDC) is proposed to correct the global and local orbit simultaneously. Numerical simulations are presented with the case of High Energy Light Source (HEPS) by comparing classic algorithms. The results show that SVDC is very effective for orbit correction and very easy to implement.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB062
About •	paper received ※ 09 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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THPRB092	Reduction of Beam Induced RF-Heating in the Horizontal Stripline Kicker at the TPS	4035
	P.J. Chou, C.K. Chan, C.-C. Chang, K.T. Hsu, K.H. Hu, C.K. Kuan, I.C. Sheng NSRRC, Hsinchu, Taiwan
	In preparation for 500 mA operation at the Taiwan Pho-ton Source (TPS), we redesigned the horizontal stripline kicker for the beam feedback system to gain a smaller loss factor with higher shunt impedance. We introduced ground fenders (see Fig. 1) to this new design which resulted in the reduction of the loss factor and substantial increase of the kicker shunt impedance. The transverse profile of the kicker electrodes was matched to the race-track beam pipe in the straight sections to minimize broadband impedance. The ground fenders can reduce the leakage of image currents through the gaps between the two strip line electrodes and also help to achieve a better impedance matching for the TEM modes in the transmission lines formed by the stripline electrodes and beam pipe in the kicker. The RF design and analysis of trapped resonant modes in the kicker were simulated by the 3-D electromagnetic code GdfidL [1]. Results of the RF design and analysis of trapped resonant modes will be discussed together with analytical estimates of coupled bunch instabilities at a beam current of 500 mA.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB092
About •	paper received ※ 17 April 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRB096	Real-Time Beam Orbit Stabilisation to 200 Nanometres in Single-Pass Mode Using a High-Precision Dual-Phase Feedback System	4049
	D.R. Bett, P. Burrows, G.B. Christian, C. Perry, R.L. Ramjiawan JAI, Oxford, United Kingdom
	A high-resolution, low-latency, stripline beam position monitor (BPM) system has been developed for use at particle accelerators and beamlines that operate with trains of particle bunches with bunch separations as low as several tens of nanoseconds, such as future linear electron-positron colliders and free-electron lasers. The system consists of fast analogue stripline BPM signal processors input to a custom FPGA-based digital feedback board which drives a pair of kickers local to the BPMs and nominally orthogonal in phase in closed-loop feedback mode, thus achieving both beam position and angle stabilisation. The feedback system was tested with the electron beam in the extraction line of the Accelerator Test Facility at the High Energy Accelerator Research Organization (KEK) in Japan. Recent upgrades to the BPMs have increased the single-shot, real-time position resolution of the system to ~150 nm for a beam charge of 1.3 nC. We report the latest results which demonstrate the feedback system operating at this resolution limit and a beam stabilisation performance of 200 nm.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB096
About •	paper received ※ 13 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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THPRB104	Improvements in Long-Term Orbit Stability at NSLS-II	4070
	Y. Hidaka, A. Caracappa, Y. Hu, B. Podobedov, R.M. Smith, Y. Tian, G.M. Wang BNL, Upton, Long Island, New York, USA
	Funding: The study is supported by U.S. DOE under Contract No. DE-SC0012704. We report our latest efforts to further improve long-term orbit stability at NSLS-II, on top of what is already provided by fast orbit feedback (FOFB) system. A DC local bump generation program, only utilizing RF beam position monitors (BPM) and compatible with FOFB, was first implemented and deployed in operation successfully, allowing on-demand fine adjustments of beamline source positions and angles. Then we introduced a simple feedback version that performs these bump corrections automatically as needed to maintain the sources within in 1 um/urad for select beamlines. In addition, an RF frequency feedback was also implemented to improve stability for 3-pole wigglers and bending magnet users. As a parallel effort, X-ray BPMs were included in a local feedback system to stabilize photon beam motion for several ID beamlines. However, this feedback scheme is not transparent to FOFB, and suspected to be the source of occasional saturation of fast corrector strength. As an alternative solution, the local bump program and its feedback version has been recently upgraded to include bumps with X-ray BPMs and in operation since April 2019.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB104
About •	paper received ※ 19 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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THPRB112	Commission of the Transverse Bunch-by-Bunch Feedback at SPEAR3	4081
	K. Tian, W.J. Corbett, X. Huang, N. Kurita, D.J. Martin, J.A. Safranek, J.J. Sebek SLAC, Menlo Park, California, USA D. Teytelman Dimtel, San Jose, USA
	Funding: Work supported by US Department of Energy Contract DE-AC03-76SF00515. Driven by the demand of suppressing transverse beam instabilities and developing novel short pulse operation modes in SPEAR3 storage ring, a wide-band transverse bunch-by-bunch feedback system has been recently commissioned for SPEAR3 storage ring. The system was demonstrated to be sufficient to suppress the transverse coupled bunch instabilities caused by trapped RF modes in one of the in vacuum insertion devices. A new function of beam instability interlock has been developed and is part of machine protection system for the in vacuum insertion device. In addition, the bunch-by-bunch feedback system serves as a indispensable diagnostic tool that enables us to measure machine parameters, beam impedance, and characteristics of the beam instability modes. In this paper, we describe the scheme and performance of the bunch-by-bunch feedback system at SPEAR3.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB112
About •	paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Hardware and Firmware Development for Enhanced Orbit Diagnostics at the Australian Synchrotron

3802

S. Chen, R.B. Hogan, A. Michalczyk, A.C. Starritt, Y.E. Tan
AS - ANSTO, Clayton, Australia

The Enhanced Orbit Diagnostic (EOD) features will be an expansion to the existing Fast Orbit Feedback (FOFB) system that is currently in operation. The new system will add the capability of online cor-rector-to-position response matrix calculation; this will significantly reduce the required measurement time. The new features will allow the injection of PRBS noise or sinusoidal signals into correctors, to characterise and monitor the FOFB system’s parameters and performance and track it over time. The system will be built based on a Xilinx ZYNQ Sys-tem-on-Module (SOM) mounted on an in-house designed motherboard to which the existing FOFB daughter board is plugged into.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB004

About •

paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRB005

Orbit Feedback and Beam Stability at the Australian Synchrotron

3805

A.C. Starritt, A. Pozar, Y.E. Tan
AS - ANSTO, Clayton, Australia

The Australian Synchrotron (AS) is a 3rd generation light source which has been in operation since 2006. Measurement of the storage ring’s beam position is provided by 98 beam position monitors, and corrections can be applied using 42 horizontal and 56 vertical slow corrector magnets, and 42 horizontal and 42 vertical fast corrector magnets. This paper provides a background describing the feedback strategies adopted at the AS leading to the current integrated orbit feedback system, together with a description of the beam position analyse techniques currently in use. It will also highlight some of the issues encountered with the system and how they were overcome. The paper also describes planned improvements, including the enhanced orbit diagnostics functionality we are intending to introduce in the next 12 months.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB005

About •

paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRB023

An MTCA.4 Based Position Feedback Application Using Laserinterferometers

3853

K.P. Przygoda, Ł. Butkowski, S. Pfeiffer, H. Schlarb, P. Wiljes
DESY, Hamburg, Germany

To perform experiments on the nanometer scale at high brilliant x-ray light sources, it is highly recommended to have the mechanical components of the experiment, like lenses, mirrors and samples, as stable as possible. Since these components need to move from nanometer up to millimeter range they cannot be stabilized by only using rigid structures. For that reason an active stabilization system with fast and precise sensors needs to be developed. Here a Laserinterferometer is used, which provides picometer resolution at several MHz sample rate. In this paper we will present a laboratory setup which consists of a 6-slot Micro Telecommunication Computing Architecture generation 4 (MTCA.4) crate with standard components such MicroTCA carrier hub (MCH), central processing unit (CPU), power supply (PS) and cooling unit (CU). The Interferometer application has been setup with Deutsches Elektronen-Synchrotron (DESY) advanced mezzanine card (DAMC-FMC20) data processing unit, DESY Field Programmable Gate Array (FPGA) mezzanine card (DFMC-UNIO) universal input and output extension and DESY rear transition module (DRTM-PZT4) piezo driver. The encoder signals given by the interferometer controller are processed within the FPGA and then forwarded to the piezo amplifier RTM-board. The signal processing application includes decoding the digital feedback signal, calculating the coordinate transform for specific experimental setups and closed-loop operation based on a proportional integral derivative (PID) controller. The first results of the laboratory setup are demonstrated and briefly discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB023

About •

paper received ※ 12 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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THPRB037

Improved Frequency Characteristics Using Multiple Stripline Kickers

3893

T. Toyama, A. Kobayashi, H. Kuboki, M. Okada
KEK, Tokai, Ibaraki, Japan

One of the important ingredient in the intra-bunch transverse feedback is a kicker. The frequency characteristics of the kicker suffers from the transit-time factor, sin(kl)/kl. We examine the frequency characteristics of multiple kickers system. Relation between the excitation patterns of the multiple kickers and the frequency characteristics are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB037

About •

paper received ※ 23 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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THPRB054

Design of a Ultrafast Stripline Kicker for Bunch-by-Bunch Feedback

3931

J. Wang, P. Li, D. Wu, D.X. Xiao, L.G. Yan
CAEP/IAE, Mianyang, Sichuan, People’s Republic of China

Lorentz force detuning and beam loading effect of the rf cavities will induce a slope of the cavity gradient. Combed with the cavity misalignments, transverse position of subsequent bunches will differ from each other. The CAEP THz Free Electron Laser facility(CTFEL) will have a fast transverse bunch-by-bunch feedback system on its test beamline, which is used to correct the beam position differences of individual bunches in the macro-pulses. The time response of the kicker is rigid for the interval of the micro-pulses is 18.5ns and will upgrade to about 2 ns, requiring impedance matching of the kicker with the power source and transmission system in a high bandwidth. Also, the electromagnetic field must reach the requirements of the beam parameters. In this paper, the structure design and the optimization of the geometric parameters of the ultrafast stripline kicker is presented. The characteristic impedance, transmission characteristics, field consistency are analyzed and optimized. And the feedback signal generation scheme for continuous bunch trains was proposed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB054

About •

paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRB062

New Orbit Correction Method Based on SVDC Algorithm for Ring Based Light Sources

3943

X.Y. Huang, J.S. Cao, Y.Y. Du, Y.H. Lu, H.Z. Ma, Y.F. Ma, Y.F. Sui, S.J. Wei, Y. Wei, Q. Ye, X.E. Zhang, D.C. Zhu
IHEP, Beijing, People’s Republic of China

Funding: Union Foundation of excellent post-doctoral of China
Orbit feedback system is essential for realizing the exceeding beam stability in modern ring based light sources. Most advanced light sources adopt the global correction scheme by using singular value decomposition (SVD) algorithm. In this paper, a new SVD with constraints method (SVDC) is proposed to correct the global and local orbit simultaneously. Numerical simulations are presented with the case of High Energy Light Source (HEPS) by comparing classic algorithms. The results show that SVDC is very effective for orbit correction and very easy to implement.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB062

About •

paper received ※ 09 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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THPRB092

Reduction of Beam Induced RF-Heating in the Horizontal Stripline Kicker at the TPS

4035

P.J. Chou, C.K. Chan, C.-C. Chang, K.T. Hsu, K.H. Hu, C.K. Kuan, I.C. Sheng
NSRRC, Hsinchu, Taiwan

In preparation for 500 mA operation at the Taiwan Pho-ton Source (TPS), we redesigned the horizontal stripline kicker for the beam feedback system to gain a smaller loss factor with higher shunt impedance. We introduced ground fenders (see Fig. 1) to this new design which resulted in the reduction of the loss factor and substantial increase of the kicker shunt impedance. The transverse profile of the kicker electrodes was matched to the race-track beam pipe in the straight sections to minimize broadband impedance. The ground fenders can reduce the leakage of image currents through the gaps between the two strip line electrodes and also help to achieve a better impedance matching for the TEM modes in the transmission lines formed by the stripline electrodes and beam pipe in the kicker. The RF design and analysis of trapped resonant modes in the kicker were simulated by the 3-D electromagnetic code GdfidL [1]. Results of the RF design and analysis of trapped resonant modes will be discussed together with analytical estimates of coupled bunch instabilities at a beam current of 500 mA.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB092

About •

paper received ※ 17 April 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019

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reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRB096

Real-Time Beam Orbit Stabilisation to 200 Nanometres in Single-Pass Mode Using a High-Precision Dual-Phase Feedback System

4049

D.R. Bett, P. Burrows, G.B. Christian, C. Perry, R.L. Ramjiawan
JAI, Oxford, United Kingdom

A high-resolution, low-latency, stripline beam position monitor (BPM) system has been developed for use at particle accelerators and beamlines that operate with trains of particle bunches with bunch separations as low as several tens of nanoseconds, such as future linear electron-positron colliders and free-electron lasers. The system consists of fast analogue stripline BPM signal processors input to a custom FPGA-based digital feedback board which drives a pair of kickers local to the BPMs and nominally orthogonal in phase in closed-loop feedback mode, thus achieving both beam position and angle stabilisation. The feedback system was tested with the electron beam in the extraction line of the Accelerator Test Facility at the High Energy Accelerator Research Organization (KEK) in Japan. Recent upgrades to the BPMs have increased the single-shot, real-time position resolution of the system to ~150 nm for a beam charge of 1.3 nC. We report the latest results which demonstrate the feedback system operating at this resolution limit and a beam stabilisation performance of 200 nm.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB096

About •

paper received ※ 13 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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THPRB104

Improvements in Long-Term Orbit Stability at NSLS-II

4070

Y. Hidaka, A. Caracappa, Y. Hu, B. Podobedov, R.M. Smith, Y. Tian, G.M. Wang
BNL, Upton, Long Island, New York, USA

Funding: The study is supported by U.S. DOE under Contract No. DE-SC0012704.
We report our latest efforts to further improve long-term orbit stability at NSLS-II, on top of what is already provided by fast orbit feedback (FOFB) system. A DC local bump generation program, only utilizing RF beam position monitors (BPM) and compatible with FOFB, was first implemented and deployed in operation successfully, allowing on-demand fine adjustments of beamline source positions and angles. Then we introduced a simple feedback version that performs these bump corrections automatically as needed to maintain the sources within in 1 um/urad for select beamlines. In addition, an RF frequency feedback was also implemented to improve stability for 3-pole wigglers and bending magnet users. As a parallel effort, X-ray BPMs were included in a local feedback system to stabilize photon beam motion for several ID beamlines. However, this feedback scheme is not transparent to FOFB, and suspected to be the source of occasional saturation of fast corrector strength. As an alternative solution, the local bump program and its feedback version has been recently upgraded to include bumps with X-ray BPMs and in operation since April 2019.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB104

About •

paper received ※ 19 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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THPRB112

Commission of the Transverse Bunch-by-Bunch Feedback at SPEAR3

4081

K. Tian, W.J. Corbett, X. Huang, N. Kurita, D.J. Martin, J.A. Safranek, J.J. Sebek
SLAC, Menlo Park, California, USA
D. Teytelman
Dimtel, San Jose, USA

Funding: Work supported by US Department of Energy Contract DE-AC03-76SF00515.
Driven by the demand of suppressing transverse beam instabilities and developing novel short pulse operation modes in SPEAR3 storage ring, a wide-band transverse bunch-by-bunch feedback system has been recently commissioned for SPEAR3 storage ring. The system was demonstrated to be sufficient to suppress the transverse coupled bunch instabilities caused by trapped RF modes in one of the in vacuum insertion devices. A new function of beam instability interlock has been developed and is part of machine protection system for the in vacuum insertion device. In addition, the bunch-by-bunch feedback system serves as a indispensable diagnostic tool that enables us to measure machine parameters, beam impedance, and characteristics of the beam instability modes. In this paper, we describe the scheme and performance of the bunch-by-bunch feedback system at SPEAR3.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB112

About •

paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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