Keyword: feedback
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MO2I02 Fast Orbit Feedback for Diamond-II controls, storage-ring, simulation, electron 1
  • I. Kempf, M.G. Abbott, L. Bobb, G.B. Christian
    DLS, Harwell, United Kingdom
  • S. Duncan
    University of Oxford, Oxford, United Kingdom
  • G. Rehm
    HZB, Berlin, Germany
  Funding: Diamond Light Source and Engineering and Physical Sciences Research Council
The electron beam stability is critical for 4th generation light sources. As opposed to 10% of beam size up to 140 Hz at Diamond, advances in detector speed and resolution at Diamond-II increase the stability requirements to 3% up to 1 kHz. This paper presents a novel control methodology for the fast orbit feedback at Diamond-II, which will stabilise the beam using two arrays of 252 slow and 144 fast correctors and 252 beam position monitors at 100 kHz. In contrast to existing approaches that separate slow and fast feedback loops, our approach is based on a two-matrix factorisation called the generalised singular value decomposition (GSVD), which decouples the system into 144 two-input modes controlled by slow and fast magnets and 108 modes controlled by slow magnets only. The GSVD-based controller is implemented in the existing Diamond storage ring using a centralised communication architecture, such as planned for Diamond-II. We present results from the Diamond storage ring and simulation, which confirm that the proposed approach meets the target specification for Diamond-II.
slides icon Slides MO2I02 [3.686 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-IBIC2023-MO2I02  
About • Received ※ 06 September 2023 — Revised ※ 07 September 2023 — Accepted ※ 11 September 2023 — Issue date ※ 18 September 2023
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MO2C03 Coupled Bunch Mode Zero Correction within the Orbit Feedback Bandwidth operation, synchrotron, controls, lattice 7
  • P.S. Kallakuri, A.R. Brill, J. Carwardine, L. Emery, N. Sereno
    ANL, Lemont, Illinois, USA
  Funding: Work supported by U. S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357.
The fast orbit feedback (FOFB) bandwidth for Advanced photon source upgrade (APS-U) will be DC-1 kHz and the synchrotron frequency will be between 100-560 Hz. This frequency overlap places coupled bunch mode 0 (CBM0) induced horizontal orbit motion inside the orbit feedback bandwidth, potentially affecting our ability to achieve beam stability goals. Longitudinal feedback kicker is not strong enough to damp CBM0 oscillations. We developed new beam-based feedback method to suppress CBM0 oscillations with low level RF phase as actuator. It uses existent FOFB framework with no changes to the feedback algorithm. Effectiveness of this method is verified using present APS operations lattice where synchrotron frequency is outside orbit feedback bandwidth*. In the present work, low alpha lattice is created to emulate APS-U setting where synchrotron frequency is inside the orbit feedback bandwidth. Experiments with this lattice successfully demonstrated CBM0 correction within FOFB bandwidth. Combined operation of orbit feedback and CBM0 correction is stable, and CBM0 oscillations are damped. We achieved better orbit motion suppression and corrector drive efforts are reduced as well.
* P. Kallakuri et al., ’Coupled bunch mode zero correction using orbit measurements and RF system phase feedback’, doi:10.1103/PhysRevAccelBeams.25.082801
slides icon Slides MO2C03 [1.326 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-IBIC2023-MO2C03  
About • Received ※ 14 July 2023 — Revised ※ 07 September 2023 — Accepted ※ 13 September 2023 — Issue date ※ 25 September 2023
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MO2C04 SOLEIL New Platform for Fast Orbit Feedback controls, FPGA, electron, electronics 11
  • R. Bronès, A. Bence, J. Bisou, N. Hubert, D. Pédeau, G. Pichon
    SOLEIL, Gif-sur-Yvette, France
  SOLEIL is upgrading its Fast Orbit Feedback platform to withstand coming obsolescence of electronic BPM and future evolutions of the machine. This new platform has to be compatible with current boundary devices such as BPM electronics or corrector power supplies, but it also shall evolve to interface future versions of these systems. A MTCA based platform was designed and installed. It is integrated in the control system by mean of a OPCUA server, and care has been taken to seamlessly toggle the closing of the feedback loop on the former or new FOFB platform. This paper will present the first tests and results conducted to commission this new system.  
slides icon Slides MO2C04 [30.176 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-IBIC2023-MO2C04  
About • Received ※ 06 September 2023 — Revised ※ 09 September 2023 — Accepted ※ 26 September 2023 — Issue date ※ 01 October 2023
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MOP030 Developments of 4GSR BPM Electronics electronics, electron, storage-ring, controls 87
  • S.W. Jang, G. Hahn, J.Y. Huang, C. Kim, D. Kim, G. Kim, B.K. Shin, D.C. Shin, D. Song
    PAL, Pohang, Republic of Korea
  • W.J. Song
    POSTECH, Pohang, Republic of Korea
  The emittance of the 4th-generation storage ring (4GSR) to be constructed in Cheongju-Ochang, Korea, is expected to be approximately 100 times smaller than the existing 3rd-generation storage ring. With the decrease in emittance, more precise beam stabilization is required. To meet this requirement, the resolution of the beam position monitor (BPM) system also needs to be further improved. We have conducted research and development on the electronics of the BPM system for the 4GSR storage ring. In order to perform fast orbit feedback in the 4GSR storage ring, we need to acquire turn-by-turn beam position data, with a desired beam position resolution of 1 ¿m. Additionally, prototypes of the bunch-by-bunch monitoring system are being developed for the transverse feedback system and longitudinal feedback system. The internally developed electronics are intended to be modified for future use as monitors for multi-bunch beam energy measurements at the end of the linear accelerator, by adjusting the logic accordingly. In this presentation, we will describe more details of the current status of the development of the beam position monitor electronics for the 4GSR in Korea.  
poster icon Poster MOP030 [24.607 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-IBIC2023-MOP030  
About • Received ※ 05 September 2023 — Revised ※ 11 September 2023 — Accepted ※ 14 September 2023 — Issue date ※ 19 September 2023
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MOP037 Tune Feedback at the Canadian Light Source quadrupole, injection, operation, storage-ring 106
  • W.A. Wurtz, C.K. Baribeau, A.M. Duffy
    CLS, Saskatoon, Saskatchewan, Canada
  In order to maintain good injection efficiency for top-up operation at the Canadian Light Source, we must keep the betatron tunes constant even as changes in insertion device fields cause the tunes to vary. To meet this requirement, we implemented a tune feedback system. We measure the tunes at a rate of 1 Hz using Dimtel bunch-by-bunch systems. The transverse feedback function of the bunch-by-bunch systems provides tune measurements without disturbing the electron beam. We adjust two quadrupole families at a rate of 0.25 Hz to control the horizontal and vertical tunes. In this article we describe the tune feedback system, its development and its performance. The system has proven to be very robust, enabling reliable top-up operation.  
poster icon Poster MOP037 [1.284 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-IBIC2023-MOP037  
About • Received ※ 24 August 2023 — Revised ※ 07 September 2023 — Accepted ※ 14 September 2023 — Issue date ※ 21 September 2023
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MOP041 Modified Fast Orbit Feedback Controller for Disturbance Attenuation in Long Straights for Diamond-II controls, simulation, target, electron 119
  • S. Banerjee, M.G. Abbott, L. Bobb, I. Kempf
    DLS, Harwell, United Kingdom
  • I. Kempf
    University of Oxford, Oxford, United Kingdom
  At Diamond Light Source, the fast orbit feedback (FOFB) uses one array of correctors and the controller is designed using the internal model control (IMC) structure. The Diamond-II upgrade will introduce an additional array of fast correctors and a new controller that is designed using the generalised modal decomposition, increasing the overall closed-loop bandwidth from 140 Hz to 1 kHz. Although simulation results have shown that the resulting beam displacement is within specification in all straights, they have also shown that the performance on long straights is limited, particularly in the vertical plane. In this paper, the controller is tuned in order to increase the FOFB performance in long straights by introducing a mode-by-mode regularisation parameter. The performance of the controller beyond 1 kHz is assessed using new disturbance data and a new measurement noise model, showing that the Diamond-II performance criteria are met, even in the presence of measurement noise.  
DOI • reference for this paper ※ doi:10.18429/JACoW-IBIC2023-MOP041  
About • Received ※ 07 September 2023 — Revised ※ 09 September 2023 — Accepted ※ 13 September 2023 — Issue date ※ 16 September 2023
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MOP043 Using Lag Compensator in Orbit Feedback power-supply, vacuum, operation, simulation 123
  • I. Pinayev
    BNL, Upton, New York, USA
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy
Growing demand on the beam orbit stability requires higher loop gain within the operational bandwidth. Increasing the gain leads to the increase of the unity gain frequency and creates problems with systems stability due to the additional phase shifts caused by the trims (power supplies, eddy currents in vacuum chambers, etc.) and filtering of beam position data. Conventionally employed systems have 20 dB/decade slope near the unity gain providing 90 degrees phase shift which is sufficient for stability. Utilizing one or more lag compensators allows to increase the gain at low frequencies while keeping phase margin acceptable. The paper provides more details on the proposed solution as well as simulations of how the transients will be modified.
poster icon Poster MOP043 [0.230 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-IBIC2023-MOP043  
About • Received ※ 25 August 2023 — Revised ※ 08 September 2023 — Accepted ※ 13 September 2023 — Issue date ※ 23 September 2023
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TU1I01 Beam Instrumentation Challenges for High-Energy and Low-Emittance Beam at SuperKEKB detector, luminosity, radiation, electron 131
  • G. Mitsuka
    KEK, Ibaraki, Japan
  The SuperKEKB electron-positron collider, which started the commissioning in February 2016, is a luminosity frontier machine for the search for new physics. In this presentation, we review the main challenges we face for the high-energy and low-emittance beam at SuperKEKB, fast and low-noise beam-orbit feedback system, X-ray beam-profile monitors for measurements for the beam size of ¿10 um, novel diamond mirrors with extremely high thermal conductivity for extracting synchrotron radiation, and various type’s beam loss diagnostics for the identification or possibly early detection of sudden beam losses. This presentation includes future directions of the R&D–-X-ray interferometry for micron-level beam size measurements and fast optics measurements with the gated turn-by-turn BPMs–-towards next-generation light source facilities and high-energy colliders.  
slides icon Slides TU1I01 [5.927 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-IBIC2023-TU1I01  
About • Received ※ 06 September 2023 — Revised ※ 13 September 2023 — Accepted ※ 14 September 2023 — Issue date ※ 27 September 2023
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TUP002 Development of Bunch Position Monitors to Observe Sudden Beam Loss of SuperKEKB Rings luminosity, detector, operation, vacuum 179
  • M. Tobiyama, H. Ikeda, G. Mitsuka
    KEK, Ibaraki, Japan
  In the SuperKEKB rings, we have encountered extremely-fast beam losses occurring primarily within one to two turns in some parts of the bunch train. Such ¿sudden beam loss¿ induced severe failure in the vertical collimator heads, quenches on the superconducting final quadrupoles, and damage on the Belle II detector in some cases. Thus it is essential to investigate the cause and take countermeasures. This paper presents the phenomena clarified by the bunch current and position monitor of the bunch feedback system. The upgrade plan for the existing monitor, and recently developed simple monitors installed in the suspected area is also introduced.  
poster icon Poster TUP002 [0.727 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-IBIC2023-TUP002  
About • Received ※ 06 September 2023 — Revised ※ 08 September 2023 — Accepted ※ 13 September 2023 — Issue date ※ 27 September 2023
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TUP046 Status of the RFSoC-based Signal Processing for Multi-bunch and Filling Pattern Feedbacks in the SLS 2.0 controls, storage-ring, software, real-time 297
  • P.H. Baeta Neves Diniz Santos
    PSI, Villigen PSI, Switzerland
  Having effectively evaluated the RF System-On-Chip (RFSoC) as a suitable technology for the SLS2.0 Filling Pattern Feedback (FPFB) and Multi-bunch Feedback (MBFB) [1], our current focus lies in realizing and expanding the required real-time Digital Signal Processing (DSP) algorithms on an RFSoC evaluation board. This contribution outlines the present status of our feedback systems, including recent outcomes derived from testing prototypes both in the laboratory and with beam signals at the storage ring.
[1] P. Baeta et al., "RF System-on-Chip for Multi-Bunch and Filling-Pattern Feedbacks," Proc. IBIC’22
poster icon Poster TUP046 [1.201 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-IBIC2023-TUP046  
About • Received ※ 30 August 2023 — Revised ※ 09 September 2023 — Accepted ※ 12 September 2023 — Issue date ※ 29 September 2023
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WE2C02 Software Defined Radio Based Feedback System for Transverse Beam Excitation controls, extraction, software, detector 306
  • P.J. Niedermayer, R.N. Geißler, R. Singh
    GSI, Darmstadt, Germany
  Funding: This project has received funding from the European Union¿s Horizon 2020 Research and Innovation programme under GA No 101004730.
Controlling stored beams in particle accelerators requires specially designed RF signals, such as needed for spill control via transverse excitation. The software-defined radio (SDR) technology is adopted as a low cost, yet highly flexible setup to generate such signals in the kHz to MHz regime. A feedback system is build using a combination of digital signal processing with GNU Radio and RF Network-on-Chip (RFNoC) on a Universal Software Radio Peripheral (USRP). The system enables digitization of signals from particle detectors and direct tuning of the produced RF waveforms via a feedback controller – implemented on a single device. To allow for triggered operation and to reduce the loop delay to a few ms, custom OOT and RFNoC blocks have been implemented. This contribution reports on the implementation and first test results with beam of the developed spill control system.
slides icon Slides WE2C02 [2.683 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-IBIC2023-WE2C02  
About • Received ※ 05 September 2023 — Revised ※ 12 September 2023 — Accepted ※ 15 September 2023 — Issue date ※ 30 September 2023
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WEP042 Implementation of Transimpedance Analog Front-End Card for Los Alamos Neutron Science Center Accelerator Wire Scanners impedance, diagnostics, beam-diagnostic, electron 442
  • D. Rai, S.A. Baily, A.J. Braido, J.I. Duran, L.S. Kennel, H.L. Leffler, D. Martinez, L.S. Montoya, D.D. Zimmermann
    LANL, Los Alamos, New Mexico, USA
  Funding: Work supported by the U.S. Department of Energy, contract no. 89233218CNA000001. LA-UR-23-25123
The Los Alamos Neutron Science Center’s (LANSCE) Accelerator Operations and Technology division group executed a project that implemented a new analog front-end card (AFE) for their wire scanner’s Data Acquisition (DAQ) system. The AFE accommodates the signal amplification and noise reduction needed to acquire essential measurement data for beam diagnostics for the LANSCE accelerator. Wire Scanners are electro-mechanical beam interceptive devices that provide cross-sectional beam profile measurement data fitted to a Gaussian distribution that provides beam shape and position information. The beam operators use the beam shape and position information to adjust parameters such as acceleration, steering and focus on delivering an optimized beam to all targets. The project implemented software and hardware that eliminated the dependency on legacy systems and consolidated various AFE designs for diagnostics systems into a single design with 11 gain settings ranging from 100 nA to 40 mA at 10 V full scale to accommodate future applications on other diagnostic systems.
poster icon Poster WEP042 [2.193 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-IBIC2023-WEP042  
About • Received ※ 07 September 2023 — Revised ※ 10 September 2023 — Accepted ※ 13 September 2023 — Issue date ※ 27 September 2023
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