Keyword: feedback
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MOAL03 Beam Commissioning of SuperKEKB Rings at Phase 1 operation, detector, injection, damping 6
  • M. Tobiyama, M. Arinaga, J.W. Flanagan, H. Fukuma, H. Ikeda, H. Ishii, K. Mori, E. Mulyani, M. Tejima
    KEK, Ibaraki, Japan
  • G. Bonvicini
    Wayne State University, Detroit, Michigan, USA
  • E. Mulyani
    Sokendai, Ibaraki, Japan
  • G.S. Varner
    University of Hawaii, Honolulu,, USA
  The Phase 1 commissioning of SuperKEKB rings with-out superconducting final focus magnets or Belle-II de-tector began in Feb., 2016. A total of 1010 mA (LER) and 870 mA (HER) stored beam has been achieved close to the design emittance and x-y coupling. Most of the beam diagnostics, including new systems such as gated turn-by-turn monitors and X-ray beam size monitors, have been commissioned with beam and proved to be essential to the success of machine commissioning. The results of the beam commissioning, including the evaluation and diffi-culties of the beam diagnostics are shown.  
slides icon Slides MOAL03 [9.607 MB]  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOAL03  
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MOBL04 LHC Online Chromaticity Measurement - Experience After One Year of Operation injection, operation, controls, hardware 20
  • K. Fuchsberger, G.H. Hemelsoet
    CERN, Geneva, Switzerland
  Hardware and infrastructural requirements to measure chromaticity in the LHC were available since the beginning. However, the calculation of the chromaticity was mostly made offline. This gap was closed in 2015 by the development of a dedicated application for the LHC control room, which takes the measured data and produces estimates for the chromaticity values immediately online and allows to correct chroma and tune accordingly. This tool proved to be essential during commissioning as well as during every injection-phase of the LHC. It became particularly important during the intensity ramp-up with 25ns where good control of the chromaticity became crucial at injection. This paper describes the concepts and algorithms behind this tool, the experience gained as well as further plans for improvements.  
slides icon Slides MOBL04 [7.414 MB]  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOBL04  
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MOPG06 First Beam Tests of the APS MBA Upgrade Orbit Feedback Controller hardware, controls, power-supply, storage-ring 39
  • N. Sereno, N.D. Arnold, A.R. Brill, H. Bui, J. Carwardine, G. Decker, B. Deriy, L. Emery, R.I. Farnsworth, T. Fors, R.T. Keane, F. Lenkszus, R.M. Lill, D.R. Paskvan, A.F. Pietryla, H. Shang, S.E. Shoaf, S. Veseli, J. Wang, S. Xu, B.X. Yang
    ANL, Argonne, Illinois, USA
  Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357
The new orbit feedback system required for the APS multi-bend acromat (MBA) ring must meet challenging beam stability requirements. The AC stability requirement is to correct rms beam motion to 10 \% the rms beam size at the insertion device source points from 0.01 to 1000 Hz. The vertical plane represents the biggest challenge for AC stability which is required to be 400 nm rms for a 4 micron vertical beam size. In addition long term drift over a period of 7 days is required to be 1 micron or less at insertion device BPMs and 2 microns for arc bpms. We present test results of the MBA prototype orbit feedback controller (FBC) in the APS storage ring. In this test, four insertion device BPMs were configured to send data to the FBC for processing into four fast corrector setpoints. The configuration of four bpms and four fast correctors creates a 4-bump and the configuration of fast correctors is similar to what will be implemented in the MBA ring. We report on performance benefits of increasing the sampling rate by a factor of 15 to 22.6 kHz over the existing APS orbit feedback system, limitations due to existing storage ring hardware and MBA orbit feedback design.
poster icon Poster MOPG06 [6.490 MB]  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG06  
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MOPG09 The Orbit Correction Scheme of the New EBS of the ESRF electronics, controls, storage-ring, sextupole 51
  • E. Plouviez, F. Uberto
    ESRF, Grenoble, France
  The ESRF storage ring is going to be upgraded into an Extremely Bright Source(EBS). The orbit correction system of the EBS ring will require 320 BPMs and 288 correctors instead of 224 BPMs and 96 correctors for the present ring. On the new ring, we are planning to reuse 192 Libera Brilliance electronics and 96 fast correctors power supplies and the 8 FPGA controllers of the present system and to add 128 new BPMs electronics and 196 new correctors power supplies. These new BPM electronics and power supplies will not have the fast 10 KHz data broadcast capability of the components of the present system. So we plan to implement an hybrid slow/ fast correction scheme on the SR of the EBS in order to reuse the present fast orbit correction system on a reduced set of the BPMs and correctors and combine this fast orbit correction with an orbit correction performed at a slower rate using the full set of BPMs and correctors. We have made simulations to predict the efficiency of this scheme for the EBS and tested on the present ring a similar orbit correction scheme using only 160 BPMs and 64 correctors for the fast corrections . We present the results of our simulations and experiments.  
poster icon Poster MOPG09 [4.054 MB]  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG09  
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MOPG11 Beam Commissioning of TPS Fast Orbit Feedback System power-supply, interface, booster, EPICS 59
  • P.C. Chiu, Y.-S. Cheng, K.T. Hsu, K.H. Hu, C.H. Huang
    NSRRC, Hsinchu, Taiwan
  Submicron orbit stability for a low emittance synchrotron light source are essential. Besides locating and removing the existing perturbations, active orbit feedback is applied to improve the orbit stability below sub-micron range from DC to a few hundreds of Hertz. Efforts to investigate orbit stability and stabilization at TPS will be addressed in this report.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG11  
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MOPG13 MicroTCA.4 Based Optical Frontend Readout Electronics and its Applications laser, electronics, operation, electron 67
  • K.P. Przygoda, L. Butkowski, M.K. Czwalinna, H. Dinter, C. Gerth, E. Janas, F. Ludwig, S. Pfeiffer, H. Schlarb, Ch. Schmidt, M. Viti
    DESY, Hamburg, Germany
  • R. Rybaniec
    Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
  In the paper the MicroTCA.4 based optical frontend readout (OFR) electronics and its applications for beam arrival time monitor (BAM) and fast beam based feed-back (BBF) is presented. The idea is to have a possibility to monitor the modulation density of the optical laser pulses by the electron bunches and apply this information for the BBF. The OFR composed of double width fast mezzanine card (FMC) and advanced mezzanine card (AMC) based FMC carrier. The FMC module consists of three optical channel inputs (data and clock), two optical channel outputs (beam arrival time), 250 MSPS ADCs, clock generator module (CGM) with integrated 2.8 GHz voltage control oscillator (VCO). The optical signals are detected with 800 MHz InGaAs photodiodes, conditioned using 2 GHz current-feedback amplifiers, filtered by 3.3 GHz differential amplifiers and next direct sampled with 16-bit 900 MHz of analog bandwidth ADCs. The CGM is used to provide clock outputs for the ADCs and for the FMC carrier with additive output jitter of less than 300 fs rms. The BAM application has been implemented using Virtex 5 FPGA and measured with its performance at Free Electron LASer in Hamburg (FLASH) facility.  
poster icon Poster MOPG13 [3.991 MB]  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG13  
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TUCL02 Novel Accelerator Physics Measurements Enabled by NSLS-II RF BPM Receivers impedance, vacuum, closed-orbit, factory 294
  • B. Podobedov, W.X. Cheng, Y. Hidaka
    BNL, Upton, Long Island, New York, USA
  • D. Teytelman
    Dimtel, San Jose, USA
  NSLS-II light source has state of the art RF BPM receivers that were designed and built in-house incorporating the latest technology available in the RF, digital, and software domains. The recently added capability to resolve the orbits of multiple bunches within a turn as well as further improvement in transverse positional resolution for single- and few-bunch fills [*] allowed us to perform a number of novel beam dynamics measurements. These include measuring small impedances of vacuum chamber components, and of extremely small (~10-5) current-dependent tune shifts (transverse and synchrotron), as well as obtaining an amplitude-dependent tune shift curve from a single kicker pulse. We are also effectively utilizing our BPMs to decipher the lifetimes of individual bunches and to visualize single bunch instability dynamics. In this paper we review the unique capabilities of NSLS-II BPMs and present examples of beam physics measurements that greatly benefit from them.
* B. Podobedov, W. Cheng, K. Ha, Y. Hidaka, J. Mead, O. Singh, K. Vetter "Single Micron Single-Bunch Turn-by-Turn BPM Resolution Achieved at NSLS-II", in Proc. IPAC'16, Busan, Korea, May 2016, WEOBB01
slides icon Slides TUCL02 [5.788 MB]  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUCL02  
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TUCL03 Measurements of Longitudinal Coupled Bunch Instabilities and Status of New Feedback System FPGA, damping, interface, kicker 298
  • G. Rehm, M.G. Abbott, A.F.D. Morgan
    DLS, Oxfordshire, United Kingdom
  We have modified the vertical bunch-by-bunch feedback to also provide a longitudinal kick on a separate input. Using our existing drive/damp system and a modulator/amplifier to the required 1.5 GHz we are thus able to characterise the damping rates of all coupled bunch instabilities, while not able to provide feedback. At the same time, we have started the development of a completely new longitudinal feedback system based on commercially available components, providing 500MS/s, 14 bit conversion in and out, powerful Virtex 7 field programmable gate array for digital signal processing and 32GB of on board buffer for recording data. We report on the status of the development and our plans to bring the new system into use.  
slides icon Slides TUCL03 [2.897 MB]  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUCL03  
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TUPG08 Design of the Transverse Feedback Kicker for ThomX impedance, kicker, simulation, dipole 329
  • M. El Ajjouri, N. Hubert, A. Loulergue, R. Sreedharan
    SOLEIL, Gif-sur-Yvette, France
  • D. Douillet, A.R. Gamelin, D. Le Guidec
    LAL, Orsay, France
  ThomX is a Compton source project in the range of the hard X rays to be installed in 2017. The machine is composed of an injector Linac and a storage ring where an electron bunch collides with a laser pulse accumulated in a FabryPerot resonator. The final goal is to provide an X-rays average flux of 1011÷1013 ph/s. To achieve this target, it is required to install a transverse feedback system to suppress instabilities generated by injection position jitter sources, resistive wall impedance or collective effects. This paper describes the design and simulation studies of the stripline kicker that will be used for the transverse feedback system.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG08  
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TUPG13 A New Stripline Kicker for PF-AR Transverse Feedback Damper kicker, impedance, damping, operation 344
  • R. Takai, T. Honda, T. Nogami, T. Obina, Y. Tanimoto, M. Tobiyama
    KEK, Ibaraki, Japan
  A feedback damper equipped with a long stripline kicker was used to damp transverse beam oscillation at the Photon Factory Advanced Ring (PF-AR), which is a 6.5-GeV synchrotron radiation source of KEK. Recently, the stripline kicker was renewed to one having shorter electrodes and a smaller loss factor because its insulating support was broken by the beam-induced thermal stress and caused frequent electric discharges inducing dust trapping phenomena. In this paper, we present details of the new stripline kicker, from design to installation, as well as demonstrate results of beam oscillation damping obtained with the new kicker.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG13  
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TUPG15 Intra-Train Position and Angle Stabilisation at ATF Based on Sub-Micron Resolution Stripline Beam Position Monitors extraction, kicker, monitoring, operation 348
  • N. Blaskovic Kraljevic, T. Bromwich, P. Burrows, G.B. Christian, C. Perry, R.L. Ramjiawan
    JAI, Oxford, United Kingdom
  • D.R. Bett
    CERN, Geneva, Switzerland
  A low-latency, sub-micron resolution stripline beam position monitoring (BPM) system has been developed and tested with beam at the KEK Accelerator Test Facility (ATF2), where it has been used to drive a beam stabilisation system. The fast analogue front-end signal processor is based on a single-stage radio-frequency down-mixer, with a measured latency of 16 ns and a demonstrated single-pass beam position resolution of below 300 nm using a beam with a bunch charge of approximately 1 nC. The BPM position data are digitised on a digital feedback board which is used to drive 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. We report the reduction in jitter as measured at a witness stripline BPM located 30 metres downstream of the feedback system and its propagation to the ATF interaction point.  
poster icon Poster TUPG15 [1.393 MB]  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG15  
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TUPG16 Performance of Nanometre-Level Resolution Cavity Beam Position Monitors and Their Application in an Intra-Train Beam Position Feedback System cavity, kicker, factory, electron 352
  • N. Blaskovic Kraljevic, T. Bromwich, P. Burrows, G.B. Christian, C. Perry, R.L. Ramjiawan
    JAI, Oxford, United Kingdom
  • P. Bambade
    LAL, Orsay, France
  • D.R. Bett
    CERN, Geneva, Switzerland
  • S.W. Jang
    Korea University Sejong Campus, Sejong, Republic of Korea
  • T. Tauchi, N. Terunuma
    KEK, Ibaraki, Japan
  A system of three low-Q cavity beam position monitors (BPMs), installed in the interaction point (IP) region of the Accelerator Test Facility (ATF2) at KEK, has been designed and optimised for nanometre-level beam position resolution. The BPMs have been used to provide an input to a low-latency, intra-train beam position feedback system consisting of a digital feedback board and a custom stripline kicker with power amplifier. The feedback system has been deployed in single-pass, multi-bunch mode with the aim of demonstrating intra-train beam stabilisation on electron bunches of charge ~1 nC separated in time by c. 220 ns. The BPMs have a demonstrated resolution of below 50 nm on using the raw measured vertical positions at the three BPMs, and has been used to stabilise the beam to below the 75 nm level. Further studies have shown that the BPM resolution can be improved to around 10 nm on making use of quadrature-phase signals and the results of the latest beam tests will be presented.  
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DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG16  
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TUPG32 Blip Scanning System Power Supply Control target, impedance, controls, software 406
  • Z. Altinbas, R.F. Lambiase, C. Theisen
    BNL, Upton, Long Island, New York, USA
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Dept. of Energy.
In the Brookhaven LINAC Isotope Producer (BLIP) facility, a fixed target is bombarded by proton beam to produce isotopes for medical research and cancer treatment. This bombardment process causes spot heating on the target and reduces its lifetime. To mitigate this problem, an upgrade to the beamline has been made by spreading the beam on the target in a circular pattern, which allows the target to heat more uniformly. The beam is steered in a circular pattern by a magnet with orthogonal (X and Y) windings. Each of these two windings is independently powered as part of a resonant circuit driven by a power amplifier. This paper describes the hardware platform used as well as the software implementation of the resonant circuit design and its feedback loops.
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DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG32  
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TUPG44 Diagnoses and Controls of Single e-Pulse Extraction at LCLS-I for the ESTB Program extraction, kicker, operation, controls 445
  • J.C. Sheppard, T.G. Beukers, W.S. Colocho, F.-J. Decker, A.A. Lutman, B.D. McKee, T.J. Smith, M.K. Sullivan
    SLAC, Menlo Park, California, USA
  A pulsed magnet is used to kick single electron bunches into the SLAC A-line from the 120 Hz LCLS-1 bunch train. These single bunches are transported to the End Station Test Beam facility. It is mandated that extraction from the LCLS beam does not disturb the non-kicked pulses. An 8 mrad kick is required to extract a bunch; without compensation the following bunch experiences a 2 urad kick; with compensation this kick is reduced to about 0.1 urad which is well within the jitter level of about 0.3 urad. Electron and photon diagnostics were used to identify problems arising from eddy currents, beam feedback errors, and inadequate monitoring and control protocol. This paper discusses the efforts to diagnose, remedy, and control the pulse snatching.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG44  
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TUPG50 Status of Beam Current Transformer Developments for FAIR ion, extraction, operation, synchrotron 461
  • M. Schwickert, F. Kurian, H. Reeg, T. Sieber
    GSI, Darmstadt, Germany
  • K. Hofmann
    TU Darmstadt, Darmstadt, Germany
  • F. Kurian
    HIJ, Jena, Germany
  • R. Neubert, P. Seidel
    FSU Jena, Jena, Germany
  • E. Soliman
    German University in Cairo, New Cairo City, Egypt
  In view of the upcoming FAIR project (Facility for Antiproton and Ion Research) several long-term development projects had been initiated with regard to diagnostic devices for beam current measurement. The main accelerator of FAIR will be the fast ramped superconducting synchrotron SIS100. Design parameters of SIS100 are acceleration of 2.5·1013 protons/cycle to 29 GeV for the production of antiprotons, as well as acceleration and slow extraction of p to U ions at 109 ions/s in the energy range of 0.4-2.7 GeV/u and extraction times of up to 10 s. For high-intensity operation non-intercepting devices are mandatory, thus the developments presented in this contribution focus on purpose-built beam current transformers. First prototype measurements of a dc current transformer based on a Tunneling Magneto Resistance sensor are presented, as well as recent achievements with a SQUID-based Cryogenic Current Comparator.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG50  
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TUPG61 Stable Transmission of RF Signals and Timing Events With Accuracy at Femtoseconds laser, timing, electron, controls 491
  • M. Liu, X.L. Dai, C.X. Yin
    SINAP, Shanghai, People's Republic of China
  Funding: Supported by the National Natural Science Foundation of China (No. 11305246) and the Youth Innovation Promotion Association CAS (No. 2016238).
We present a new design of femtosecond timing system. In the system, RF signal and timing events are transmitted synchronously in one single optical fiber with very high accuracy. Based on the theory of Michelson's interferometer, phase drift is detected with accuracy at femtoseconds. And phase compensation is accomplished in transmitter with two approaches afterwards. Moreover, the traditional event timing system is integrated into the new system to further reduce the jitter of timing triggers. The system could be applied in synchrotron light sources, free electron lasers and colliders, where distribution of highly stable timing information is required. The physics design, simulation analysis and preliminary results are demonstrated in the paper.
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG61  
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WEPG02 Commissioning of the Bunch-by-Bunch Transverse Feedback System for the TPS Storage Ring kicker, insertion-device, insertion, vacuum 612
  • Y.-S. Cheng, K.T. Hsu, K.H. Hu, C.H. Huang, C.Y. Liao
    NSRRC, Hsinchu, Taiwan
  TPS finish its Phase II commissioning in December of 2015 after installation of two superconducting RF cavities and ten sets of insertion devices in mid-2015. Storage beam current up to 520 mA was achieved. Intensive insertion devices commissioning were performed in March 2016 and delivery beam for beam-line commissioning and perform pilot experiments. One horizontal stripline kicker and two vertical stripline kickers were installed in May 2015. Bunch-by-bunch feedback system were commissioning in late 2015. Commercial available feedback processor was selected for the feedback system integration. Beam property and performance of the feedback system were measured. Results will summary in this report.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG02  
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WEPG06 Orbit Feedforward and Feedback Applications in the Taiwan Light Source power-supply, operation, controls, insertion 623
  • C.H. Kuo, P.C. Chiu, K.T. Hsu, K.H. Hu
    NSRRC, Hsinchu, Taiwan
  Taiwan Light Source (TLS) is a 1.5 GeV third-generation light source with circumference 120 meters. TLS is operated at 360 mA top-up injection mode. The storage ring is 6-fold symmetry with 6-meter straight sections for injection, RF cavity, and insertion devices. There are three undulators were installed in three straight sections to delivery VUV and soft X-ray for users. Beside there undulators, a conventional wiggler (W200 installed at straight sections to provide hard X-ray to serve user. Working parameters of hard X-ray sources are fixed without cause problem on operation. However, undulators should be changing its working parameters during user experiments performed. These undulator during its gap/phase changing will create orbit perturbation due to its field errors. Orbit feedback is main tool to keep orbit without change. However, some correctors setting of the orbit feedback system are easy to saturation due to large perturbation come from U90. To keep functionality of the orbit feedback system working in good condition, combines with orbit feedback and feed-forward is proposed and reported in this conference.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG06  
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WEPG08 Fast Orbit Feedback with Linux PREEMPT_RT controls, insertion-device, cavity, insertion 630
  • Y.E. Tan
    SLSA, Clayton, Australia
  • D.J. Peake
    The University of Melbourne, Melbourne, Victoria, Australia
  • D.O. Tavares
    LNLS, Campinas, Brazil
  The fast orbit feedback system in development at the Australian Synchrotron aims to improve the stability of the electron beam by reducing the impact of insertion devices and targeting orbit perturbations at the line frequency (50 Hz, 100 Hz and 300 Hz). The system is designed to have a unity gain at a frequency greater than 300 Hz with a simple PI controller with harmonic suppressors in parallel (as was done at Elettra). With most of the system in place (position aggregation, power supplies and corrector coils) we decided to implement a PC based feedback system to test what has been installed as well as the effectiveness of the proposed control algorithms while the firmware for the FPGA based feedback processor is being developed. This paper will report on effectiveness of a feedback system built using a Linux Operating System with the PREEMPT patch running on an Intel CPU.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG08  
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WEPG43 A Procedure for the Characterization of Corrector Magnets storage-ring, electron, controls, vacuum 728
  • S. Gayadeen, M.J. Furseman, G. Rehm
    DLS, Oxfordshire, United Kingdom
  At Diamond Light source, the main assumption for the Fast Orbit Feedback (FOFB) controller design is that the corrector magnets all have the same dynamic response. In this paper, a procedure to measure the frequency responses of the corrector magnets on the Diamond Storage Ring is presented and the magnet responses are measured and compared in order to assess whether this assumption is valid. The measurements are made by exciting a single corrector magnet with a sinusoidal input and measuring the resulting sinusoidal movement on the electron beam using electron Beam Position Monitors (eBPMs). The input excitation is varied from 10 Hz to 5 kHz using a 10 mA sine wave. The amplitude ratio and the phase difference between the input excitation and the beam position excitation are determined for each input frequency and the procedure is repeated for several magnets. Variations in both gain and phase across magnets are discussed in this paper and the effect of such variations on the performance of the FOFB controller performance is determined.  
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DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG43  
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