Keyword: LLRF
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MOPOJO19 Programmable SLED System for Single Bunch and Multibunch Linac Operation klystron, linac, cavity, operation 73
 
  • C. Christou, P. Gu, A. Tropp
    DLS, Oxfordshire, United Kingdom
 
  The Diamond Light Source pre-injector linac generates single bunch and multibunch 100 MeV electron beams for top-up and fill of the storage ring. The linac is powered by two high-power 3 GHz klystrons, and both klystrons are required for reliable injection into the booster and storage ring. In order to introduce redundancy, a SLED pulse compression cavity has been installed so that the linac can operate from just one klystron, with the second klystron held as a standby. A simple phase flip can be used to generate a high-power transient RF spike, suitable for single bunch linac operation, and a programmable amplitude and phase drive profile can be specified to generate a constant-power klystron output suitable for multibunch operation. Details are presented of design, installation and high-power operation of the SLED system, and the ability to generate a long pulse, including corrections for klystron nonlinearity and deviations from modulator flat-top, is demonstrated.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOJO19  
About • Received ※ 09 August 2022 — Revised ※ 29 August 2022 — Accepted ※ 02 September 2022 — Issue date ※ 08 September 2022
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MOPOPA03 Beam-Transient-Based LLRF Voltage Signal Calibration for the European XFEL cavity, FEL, linac, operation 80
 
  • N. Walker, V. Ayvazyan, J. Branlard, S. Pfeiffer, Ch. Schmidt
    DESY, Hamburg, Germany
 
  The European XFEL linac consists of 25 superconducting RF (SRF) stations. With the exception of the first station which is part of the injector, each station comprises 32 1.3-GHz SRF TESLA cavities, driven by a single 10-MW klystron. A sophisticated state-of-the-art low-level RF (LLRF) system maintains the complex vector sum of each RF station. Monitoring and maintaining the calibration of the cavity electric field (gradient) probe signals has proven critical in achieving the maximum energy performance and availability of the SRF linac. Since there are no dedicated diagnostics for cross-checking calibration of the LLRF system, a procedure has been implemented based on simultaneously measuring the beam transient in open-loop operation of all cavities. Based on methods originally developed at FLASH, the European XFEL procedure makes use of automation and the XFEL LLRF DAQ system to provide a robust and relatively fast (minutes) way of extracting the transient data, and is now routinely scheduled once per week. In this paper, we will report on the background, implementation, analysis methods, typical results, and their subsequent application for machine operation.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOPA03  
About • Received ※ 13 August 2022 — Revised ※ 23 August 2022 — Accepted ※ 14 September 2022 — Issue date ※ 27 September 2022
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MOPOPA15 Three Years of Operation of the SPIRAL2 SC LINAC- RF Feedback cavity, linac, controls, operation 98
 
  • M. Di Giacomo, M. Aburas, P.-E. Bernaudin, O. Delahaye, A. Dubosq, A. Ghribi, J.-M. Lagniel, J.F. Leyge, G. Normand, A.K. Orduz, F. Pillon, L. Valentin
    GANIL, Caen, France
  • F. Bouly
    LPSC, Grenoble Cedex, France
  • S. Sube
    CEA-DRF-IRFU, France
 
  The superconducting LINAC of SPIRAL2 at the GANIL facility has been in operation since October 2019. The accelerator uses 12 low beta and 14 high beta supercon-ducting quarter wave cavities, cooled at 4°K, working at 88 MHz. The cavities are operated at a nominal gradient of 6.5 MV/m and are independently powered by a LLRF and a solid-state amplifier, protected by a circulator. Pro-ton and deuteron beam currents can reach 5 mA and beam loading perturbation is particularly strong on the first cavities, as they are operated at field levels much lower than the nominal one. This paper presents a feedback after three years of oper-ation, focuses on the RF issues, describing problems and required improvement on the low level, control and pow-er systems  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOPA15  
About • Received ※ 14 August 2022 — Revised ※ 17 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 02 September 2022
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MOPOGE08 Low Level RF System of the Light Proton Therapy Linac linac, controls, cavity, rfq 161
 
  • D. Soriano Guillén, S. Benedetti, M. Cerv, G. De Michele, Ye. Ivanisenko
    AVO-ADAM, Meyrin, Switzerland
 
  The LIGHT (Linac for Image-Guided Hadron Therapy) project was initiated to develop a modular proton accelerator delivering beam with energies up to 230 MeV for cancer therapy. The machine consists of three different kinds of accelerating structures: RFQ (Radio-Frequency Quadrupole), SCDTL (Side Coupled Drift Tube Linac) and CCL (Coupled Cavity Linac). These accelerating structures operate at 750 MHz (RFQ) and 3 GHz (SCDTL, CCL). The accelerator RF signals are generated, distributed, and controlled by a Low-Level RF (LLRF) system. The LIGHT LLRF system is based on a commercially available solution from Instrumentation Technologies with project specific customization. This LLRF system features high amplitude and phase stability, monitoring of the RF signals from the RF network and the accelerating structures at 200 Hz, RF pulse shaping over real-time interface integrated, RF breakdown detection, and thermal resonance frequency correction feedback. The LLRF system control is integrated in a Front-End Controller (FEC) which connects it to the LIGHT control system. In this contribution we present the main features of the AVO LLRF system, its operation and performance.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOGE08  
About • Received ※ 16 August 2022 — Revised ※ 25 August 2022 — Accepted ※ 28 August 2022 — Issue date ※ 05 September 2022
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TUPORI20 The Impact of Beam Loading Transients on the RF System and Beam Breakup Instabilities in Energy Recovery Linacs cavity, beam-loading, simulation, linac 593
 
  • S. Setiniyaz
    Lancaster University, Lancaster, United Kingdom
  • R. Apsimon, M.J.W. Southerby
    Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
  • P.H. Williams
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
 
  In multi-turn Energy Recovery Linacs (ERLs), the filling pattern describes the order that which bunches are injected into the ERL ring. The filling patterns and recombination schemes together can create various beam loading patterns/transients, which can have a big impact on the RF system, namely the cavity fundamental mode voltage, required RF power, and beam breakup instability. In this work, we demonstrate one can lower the cavity voltage fluctuation and rf power consumption by carefully choosing the right transient by using an analytical model and simulation.  
poster icon Poster TUPORI20 [0.659 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPORI20  
About • Received ※ 19 August 2022 — Revised ※ 28 August 2022 — Accepted ※ 29 August 2022 — Issue date ※ 31 August 2022
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TH1AA06 Low Level RF Control Algorithms for the CERN Proton LINAC4 cavity, linac, klystron, beam-loading 673
 
  • P. Baudrenghien, B. Bielawski, R.B. Borner
    CERN, Meyrin, Switzerland
 
  The CERN Linac4 Low Level RF (LLRF) uses a Linear Gaussian Regulator and an Adaptive Feed Forward to regulate the accelerating field in the cavities in the presence of strong beam loading. A Klystron Polar Loop is also implemented to compensate the RF perturbations caused by the ripples and droop in the klystron High Voltage supply. The talk presents the important parts of the regulation, shows results as the system has evolved from first prototype (2013) to operational beams (2020), and mentions some important issues encountered during the commissioning and the first years of operation, with their mitigations.  
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TH1AA06  
About • Received ※ 24 August 2022 — Revised ※ 31 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 06 September 2022
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THPOPA12 Development and Integration of a New Low-Level RF System for MedAustron cavity, controls, synchrotron, hardware 764
 
  • M. Wolf, M. Cerv, C. Kurfürst, G. Muyan, S. Myalski, M. Repovž, C. Schmitzer
    EBG MedAustron, Wr. Neustadt, Austria
  • A. Bardorfer, B. Baričevič, P. Paglovec, M. Škabar
    I-Tech, Solkan, Slovenia
 
  The MedAustron Ion Therapy Centre is a synchrotron-based particle therapy facility, which delivers proton and carbon beams for clinical treatments. Currently, the facility treats 40 patients per day and is improving its systems and workflows to further increase this number. Although MedAustron is a young and modern center, the life-cycle of certain crucial control electronics is near end-of-life and needs to be addressed. This paper presents the 216MHz injector Low-Level Radio Frequency (iLLRF) system with option of use for the synchrotron Low-Level Radio Frequency (sLLRF - 0.4-10MHz). The developed system will unify the cavity regulation for both LLRFs and will also be used for beam diagnostics (injector/synchrotron) and RF knock-out slow extraction. The new LLRF system is based on a µTCA platform which is controlled by the MedAustron Control System based on NI-PXIe. Currently, it supports fiberoptics links (SFP+), but other links (e.g. EPICS, DOOCS) can be established. The modular implementation of this LLRF allows connections to other components, such as motors, amplifiers, or interlock systems, and will increase the robustness and maintainability of the accelerator.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOPA12  
About • Received ※ 24 August 2022 — Revised ※ 25 August 2022 — Accepted ※ 31 August 2022 — Issue date ※ 01 September 2022
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THPOPA13 Superconducting Cavity and RF Control Loop Model for the SPIRAL2 Linac cavity, controls, linac, feedback 767
 
  • F. Bouly
    LPSC, Grenoble Cedex, France
  • M. Di Giacomo, J.F. Leyge, M. Tontayeva
    GANIL, Caen, France
 
  The SPIRAL2 superconducting linac has been successfully commissioned with protons in 2020. During the commissioning, a model of the cavity and its LLRF control loop has been developed. The model enables to have better understanding of the system and was used to guide the tuning of the PI(D) correctors for beam loading compensation. Here we review the development of such a tool, computed with MATLAB Simulink and using the frequency domain (Laplace transfer function) to model the cavity RF and mechanical behaviours (Lorentz detuning), as well as all elements that compose the RF control loop (digital LLRF, amplifier, transmission lines, etc.). The benchmarking of the model with measurement carried out with the proton beam is also discussed in this contribution.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOPA13  
About • Received ※ 24 August 2022 — Revised ※ 01 September 2022 — Accepted ※ 03 September 2022 — Issue date ※ 15 September 2022
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THPOPA14 MTCA.4-Based LLRF System Prototype Status for MYRRHA cavity, operation, cryomodule, EPICS 771
 
  • C. Joly, S. Berthelot, N. Gandolfo, J. Rozé, J.-F. Yaniche
    Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
  • J-L. Bolli, I. Garcia, C. Gaudin
    IOXOS Technologies, Gland, Switzerland
  • O. Bourrion, D. Tourres
    LPSC, Grenoble Cedex, France
  • S. Boussa, W. De Cock, P. Della Faille, F. Pompon, E. Verhagen
    SCK•CEN, Mol, Belgium
 
  Within the framework of MINERVA, the first Phase of MYRRHA (Multi-purpose hYbrid Research Reactor for High-tech Applications) project, IN2P3 labs are in charge of the development of several accelerator elements. Among those, a fully equipped Spoke cryomodule prototype was constructed. It integrates two superconducting single spoke cavities operating at 2K, the RF power couplers and the associated cold tuning systems. On the control side, a MTCA.4-based Low Level RadioFrequency (LLRF) system prototype has been implemented by IJCLab including FPGA specific firmware, a new µRTM frequency downconverter module from the company IOxOS Technologies and EPICS developments in collaboration with the SCK•CEN. The status of the LLRF system will be shown as well as its preliminary tests results.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOPA14  
About • Received ※ 23 August 2022 — Revised ※ 26 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 01 September 2022
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THPOPA18 Development of a Tuner Control System for Low-Energy Superconducting Linac at RAON controls, cavity, EPICS, cryomodule 778
 
  • H. Kim, M.O. Hyun, H. Jang, M.S. Kim, Y. Kim
    IBS, Daejeon, Republic of Korea
 
  Funding: This research was supported by the RISP of ibs funded by the Ministry of Science and the National Research Foundation (NRF) of the Republic of Korea under Contract 2013M7A1A1075764.
We propose a tuner control system for low-energy superconducting linac at RAON. The frequency error of the superconducting cavities must be smaller than a few of Hz to operate in beam acceleration mode. To minimize the freuqency error as much as possible, the error is calculated in the low-level RF(LLRF), and the proposed tuner control system changes the superconducting cavity frequency by using a mechanical tuner and a motor attached to the cavity directly. This control system deals with not only the initial frequency error of the cavity but also the frequency drift of the cavity induced by external disturbance such as the slow fluctuation helium pressure automatically. In addition, an automatic proportional gain calibration technique is also proposed. In this paper, the detailed operation and techniques will be described.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOPA18  
About • Received ※ 13 August 2022 — Revised ※ 23 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 11 September 2022
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THPOPA19 Initial High Power RF Driving Test Using Digital LLRF for RF Conditioning of 1 MeV/n RFQ at KOMAC rfq, controls, cavity, experiment 781
 
  • H.S. Jeong, W.-H. Jung, D.-H. Kim, H.S. Kim, J.H. Kim, K.H. Kim, S.G. Kim, H.-J. Kwon, P. Lee, Y.G. Song
    KOMAC, KAERI, Gyeongju, Republic of Korea
 
  Funding: This work was supported through the KOMAC operation fund by the Ministry of Science and ICT of Korean government.
As a part of R&D toward the RFQ based heavy ion irradiation system, the 1 MeV/n RFQ was designed, brazed, installed and commissioned by staff researchers and engineers at KOMAC of KAERI. This 1 MeV/n RFQ system includes the microwave ion source, EBIS, RFQ, quadrupole magnets, switching magnet and the target systems. The digital based Low-Level RF was developed to provide the stable accelerating field to the RFQ. This Low-Level RF has features such as direct RF detection/generation without mixer, non-IQ sampling, PI feedback control, iterative learning based feed-forward control, and the digital RF interlock. In this paper, the characteristics of Low-Level RF are described, as well as the processes and results of an initial RF driving test for the RFQ’s RF conditioning.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOPA19  
About • Received ※ 22 August 2022 — Revised ※ 28 August 2022 — Accepted ※ 29 August 2022 — Issue date ※ 15 September 2022
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THPOPA22 C-Band Low Level RF System Using COTS Components controls, timing, laser, low-level-rf 789
 
  • J.P. Edelen
    RadiaSoft LLC, Boulder, Colorado, USA
  • R.D. Berry, A. Diego, D.I. Gavryushkin, A.Yu. Smirnov
    RadiaBeam, Santa Monica, California, USA
  • J. Krasna
    COSYLAB, Control System Laboratory, Ljubljana, Slovenia
 
  Low Level RF systems have historically fallen into two categories. Custom systems developed at national laboratories or industrial systems using custom hardware specifically designed for LLRF. Recently however advances in RF technology accompanied by demand from applications like quantum computing have led to commercially available systems that are viable for building a modular low-level RF system. Here we present an overview of a Keysight based digital LLRF system. Our system employs analog upconversion and downconversion with an intermediate frequency of 100MHz. We discuss our phase-reference system and provide initial results on the system performance.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOPA22  
About • Received ※ 25 August 2022 — Revised ※ 01 September 2022 — Accepted ※ 02 September 2022 — Issue date ※ 03 September 2022
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THPOPA23 Digital LLRF System Development and Implementation at the APS Linac linac, klystron, operation, controls 792
 
  • Y. Yang, J.M. Byrd, G.I. Fystro, D.A. Meyer, A. Nassiri, A.F. Pietryla, T.L. Smith, Y. Sun
    ANL, Lemont, Illinois, USA
  • B. Baričevič
    I-Tech, Solkan, Slovenia
 
  The current analog LLRF systems which have supported the APS linac operation for over 25 years, will be replaced with digital LLRF systems utilizing the latest commercially available electronics technology. A customized LLRF system has been developed as the next-generation APS linac controller. Two systems have been manufactured and delivered to the APS. On-site tests demonstrated they met the APS linac operation requirements with the first system expected to be integrated into APS linac operation this year.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOPA23  
About • Received ※ 22 August 2022 — Revised ※ 29 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 15 September 2022
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THPOPA24 First SELAP Algorithm Operational Experience of the New LLRF 3.0 RF Control System cavity, controls, operation, FPGA 795
 
  • T.E. Plawski, R. Bachimanchi, S. Higgins, C. Hovater, J. Latshaw, C.I. Mounts
    JLab, Newport News, Virgina, USA
 
  The JLAB LLRF 3.0 system has been developed and is replacing the 30-year-old LLRF systems in the CEBAF accelerator. The LLRF system builds upon 25 years of design and operational RF control experience (digital and analog), and our recent collaboration in the design of the LCLSII LLRF system. The new system also incorporates a cavity control algorithm using a fully functional phase and amplitude locked Self Exciting Loop (SELAP). The first system (controlling 8 cavities) was installed and commissioned in August of 2021. Since then the new LLRF system has been operating with cavity gradients up to 20 MV/m, and electron beam currents up to 350 uA. This paper discusses the operational experience of the LLRF 3.0 SELAP algorithm along with other software and firmware tools like cavity and klystron characterization and quench detection.
T. E. Plawski et al., ’JLAB LLRF 3.0 Development and Tests’, in Proc. 12th Int. Particle Accelerator Conf. (IPAC’21), Campinas, Brazil, May 2021, pp
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOPA24  
About • Received ※ 10 August 2022 — Revised ※ 01 September 2022 — Accepted ※ 07 September 2022 — Issue date ※ 12 October 2022
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FR1AA03 Status and Challenges at TRIUMF ISAC Facility cavity, ISAC, linac, operation 866
 
  • Z.Y. Yao, Z.T. Ang, T. Au, K. Fong, X.L. Fu, J.J. Keir, P. Kolb, D. Lang, R.E. Laxdal, R. Leewe, Y. Ma, B. Matheson, R.S. Sekhon, B.S. Waraich, Q. Zheng, V. Zvyagintsev
    TRIUMF, Vancouver, Canada
 
  The ISAC facility uses the ISOL technique to produce radioactive ions for experiments. The post-accelerator consists of a room temperature linac (ISAC-I) and a su-perconducting linac (ISAC-II). After more than two dec-ades of beam delivery in ISAC, the RF systems have met various challenges regarding increased operation require-ments, system stability issues and performance improve-ments. This paper discusses the detailed challenges in recent years in both ISAC-I and ISAC-II. The upgrade plan or mitigation solution to address each challenge is reported respectively. A hint of the long-term vision at ISAC is also briefly described at the end of the paper.  
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-FR1AA03  
About • Received ※ 13 August 2022 — Revised ※ 21 August 2022 — Accepted ※ 29 August 2022 — Issue date ※ 01 September 2022
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