Keyword: LLRF
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TUP002 Modeling of Superconducting Spoke Cavity with its Control Loops Systems for the MYRRHA Linac Project cavity, linac, cryomodule, feedback 387
 
  • M. Dominiczak
    ACS, Orsay, France
  • F. Bouly
    LPSC, Grenoble Cedex, France
  • N. Gandolfo, C. Joly
    IPN, Orsay, France
 
  In the construction framework of a future 600 MeV/4 mA CW Superconducting Linac accelerator for the MYRRHA project at SCK’CEN (Mol, Belgium), modeling works under Matlab/Simulink are carried out upstream to understand the behaviour of 352 MHz single Spoke cavity with its environment and its associated feedback control loops (LLRF and cold tuning system). One of the main goal is to assess the feasibility of cavity failure compensation in the Superconducting Linac. Indeed, stringent reliability requirements must be fulfilled to ensure an efficient operation of the MYRRHA Accelerator Driven System: unexpected beam interruptions, due to failures, must be compensated in less than 3 seconds. Our preliminary study focuses on the fast frequency re-tuning of the cavity and the power balances. Our goal is to prepare the R&D tests foreseen at IPN Orsay on a prototype cryomodule including two SC Spoke cavities equipped with couplers, tuners with feedback loop and connected to dedicate LLRF.
Nicolas Gandolfo, IPNO, Orsay (France)
Christophe Joly, IPNO, Orsay (France)
Frédéric Bouly, LPSC, Grenoble (France)
 
poster icon Poster TUP002 [1.335 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP002  
About • paper received ※ 23 June 2019       paper accepted ※ 04 July 2019       issue date ※ 14 August 2019  
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TUP080 Tuner Design and Test for 166.6 MHz SRF Cavity of HEPS cavity, SRF, simulation, high-voltage 642
 
  • Z.H. Mi, Z.Q. Li, H.Y. Lin, W.M. Pan, Q.Y. Wang, P. Zhang, X.Y. Zhang, H.J. Zheng
    IHEP, Beijing, People’s Republic of China
 
  The 166.6 MHz superconducting RF cavities have been proposed for the High Energy Photon Source (HEPS), a 6 GeV kilometer-scale light source. The cavity is of quarter-wave type made of bulk niobium with ’=1. Each cavity will be operated at 4.2 K providing 1.2 MV accelerating. To compensate the frequency change due to manufacturing uncertainty, Lorentz force, beam loading, He pressure and microphonics the plunger tuner and gap tuner are chosen as options. Now the plunger tuner and low temperature gap tuner have been test with cavity, while the warm gap tuner is being designed. Details of the design and summary of the test results of the two type tuners with cavity are presented in this paper.  
poster icon Poster TUP080 [1.141 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP080  
About • paper received ※ 22 June 2019       paper accepted ※ 30 June 2019       issue date ※ 14 August 2019  
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WETEB4 Virtual SRF Cavity: Testing SRF Cavity Support Systems Without the Hassle of Liquid Helium and Klystrons cavity, controls, FPGA, SRF 770
 
  • P. Echevarria, J. Knobloch, A. Neumann, A. Ushakov
    HZB, Berlin, Germany
  • E. Aldekoa, J. Jugo
    University of the Basque Country, Faculty of Science and Technology, Bilbao, Spain
 
  Setting up and debugging SRF support systems, such as LLRF control, quench detection, microphonics and Lorentz-force detuning control, etc., often requires extensive time spent operating the cavities. This results in time consuming and costly operation. Early into the development stages the actual cavity system may not even be available. It is therefore highly desirable to pre-evaluate these systems under realistic conditions prior to final testing with the SRF cavities. We devised an FPGA-based "virtual cavity" that takes a regular low-level RF input and generates the signals for RF-power reflection, transmission and detuning that mimic the response of a real cavity system. As far as the user is concerned, the response is the same as for a real cavity. This "black-box" model includes mechanical modes, Lorentz force detuning, a field depended quality factor, quenches and variable input coupling and is currently being expanded. We present the model and show some applications for operating the quench detection, LLRF and microphonics control for 1.3 GHz BERLinPro cavities. The same system can be used for other cavity types, including normal conducting cavities.  
slides icon Slides WETEB4 [9.784 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-WETEB4  
About • paper received ※ 23 June 2019       paper accepted ※ 02 July 2019       issue date ※ 14 August 2019  
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THP023 RF Commissioning of the CBETA Main Linac Cryomodule cavity, operation, linac, controls 881
 
  • N. Banerjee, J. Dobbins, G.H. Hoffstaetter, R.P.K. Kaplan, M. Liepe, C.W. Miller, P. Quigley, E.N. Smith, V. Veshcherevich
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
 
  Funding: This work was performed through the support of New York State Energy Research and Development Agency (NYSERDA).
The Cornell BNL ERL Test Accelerator (CBETA) employs a superconducting Main Linac Cryomodule in order to perform multi-turn energy recovery operation. Optimizing the field stability of the low bandwidth SRF cavities in the presence of microphonics with limited available RF power is a challenging task. Despite of this, the Main Linac Cryomodule has been successfully used in CBETA to impart a maximum energy gain of 54 MeV, well above the energy gain requirement of CBETA. In this paper, we present an overview of our RF commissioning procedure including automatic coarse tuning, measurement of DAC and phase offsets. We further detail our microphonics measurements from our most recent run period.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP023  
About • paper received ※ 23 June 2019       paper accepted ※ 29 June 2019       issue date ※ 14 August 2019  
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THP049 Commissioning the JLab LERF Cryomodule Test Facility cryomodule, controls, cavity, MMI 973
 
  • C. Hovater, R. Bachimanchi, E. Daly, M.A. Drury, L.E. Farrish, J. Gubeli, N.A. Huque, K. Jordan, M.E. Joyce, L.K. King, M. Marchlik, W. Moore, T.E. Plawski, A.D. Solopova, C.M. Wilson
    JLab, Newport News, Virginia, USA
  • A.L. Benwell, C. Bianchini, D. Gonnella, S.L. Hoobler, K.J. Mattison, J. Nelson, A. Ratti, B.H. Ripman, S. Saraf, L.M. Zacarias
    SLAC, Menlo Park, California, USA
  • L.R. Doolittle, S. Paiagua, C. Serrano
    LBNL, Berkeley, California, USA
 
  The JLab Low Energy Recirculating Facility, LERF, has been modified to support concurrent testing of two LCLS-II cryomodules. The cryomodules are installed in a similar fashion as they would be in the L1 section of the LCLS-II linac, including the floor slope and using all of the LCLS-II hardware and controls for cryomodule cryogenics, vacuum, and RF (SSA and LLRF). From the start, it was intended to use LCLS-II electronics and EPICS software controls for cryomodule testing. In affect the LERF test facility becomes the first opportunity to commission and operate the LCLS-II LINAC hardware and software controls. Support for specific cryomodule high level test applications like Q0 and HOMs measurements, are being developed from the basic cryomodule control suite. To support the testing, 2 K He is supplied from the CEBAF south linac cryogenic system, where care must be taken when using the LERF test facility to not upset the CEBAF cryogenics plant. This paper discusses the commissioning of the hardware and software development for testing the first two LCLS-II cryomodules.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP049  
About • paper received ※ 22 June 2019       paper accepted ※ 02 July 2019       issue date ※ 14 August 2019  
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THP075 Development of a 166.6 MHz Digital LLRF System for HEPS-TF Project cavity, controls, low-level-rf, superconducting-cavity 1073
 
  • Q.Y. Wang, J.P. Dai, T.M. Huang, D.B. Li, H.Y. Lin, Z.H. Mi, P. Zhang
    IHEP, Beijing, People’s Republic of China
 
  A 166.6 MHz superconducting RF system has been proposed for the High Energy Photon Source (HEPS), a 6 GeV kilometer-scale light source. A 166.6MHz digital low-level RF system for HEPS-TF project has been developed firstly. And the digital low-level RF system has been successfully applied to the horizontal high power test of 166.6MHz superconducting cavity. The cavity field stability has been successfully achieved about ±0.03% (pk-pk) in amplitude and ±0.02 degree (pk-pk) in phase while the cavity field voltage is up to 1.2MV. It can meet the field stability requirements towards ±0.1% in ampli-tude and ±0.1 degree in phase of HEPS project. Further study and optimization of the system is under way.  
poster icon Poster THP075 [1.612 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP075  
About • paper received ※ 29 June 2019       paper accepted ※ 30 June 2019       issue date ※ 14 August 2019  
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THP078 CERN’s SRF Test Stand for Cavity Performance Measurements cavity, controls, operation, interface 1082
 
  • N. Stapley, J. Bastard, M.R. Coly, A.E. Ivanov, A. Macpherson, N.C. Shipman, K. Turaj
    CERN, Geneva, Switzerland
  • I. Ben-Zvi
    BNL, Upton, New York, USA
  • A. Castilla
    Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
  • K. Hernandez-Chahin
    Universidad de Guanajuato, División de Ciencias e Ingenierías, León, Mexico
  • M. Wartak, A. Zwozniak
    IFJ-PAN, Kraków, Poland
 
  Recent deployment of a digital LLRF system within the cavity testing framework of CERN’s vertical test cryostats has permitted a full revamp of cavity performance validation. With both full continuous and pulse mode operation, steady state a transient RF behaviour can be effectively probed. Due to direct and integrated control and monitoring of environmental test conditions, standard and novel RF measurement procedures have been developed and integrated into the testing infrastructure, along with a coherent data flow of high granularity measurement data. We present an overview of this cavity measurement system and address the underlying architectural structure, data handling and integration of user interfaces. In addition we highlight the benefits of variety of RF cavity measurements that can now be accommodated in our large 2 K cryostats.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP078  
About • paper received ※ 23 June 2019       paper accepted ※ 30 June 2019       issue date ※ 14 August 2019  
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