Keyword: klystron
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MOPAB146 Status of the C-Band Engineering Research Facility (CERF-NM) Test Stand Development at LANL cavity, GUI, controls, radiation 509
 
  • D. Gorelov
    Private Address, Los Alamos, USA
  • R.L. Fleming, S.K. Lawrence, J.W. Lewellen, D. Perez, M.E. Schneider, E.I. Simakov, T. Tajima
    LANL, Los Alamos, New Mexico, USA
  • M.E. Middendorf
    ANL, Lemont, Illinois, USA
  
  Funding: LDRD-DR Project 20200057DR
C-Band structures research is of increasing interest to the accelerator community. The RF frequency range of 4-6 GHz gives the opportunity to achieve significant increase in the accelerating gradient, and having the wakefields at the manageable levels, while keeping the geometric dimensions of the structure technologically convenient. Strong team of scientists, including theorists researching properties of metals under stressful thermal conditions and high electromagnetic fields, metallurgists working with copper as well as alloys of interest, and accelerator scientists developing new structure designs, is formed at LANL to develop a CERF-NM facility. A 50 MW, 5.712 GHz Canon klystron, was purchased in 2019, and laid the basis for this facility. As of Jan-21, the construction of the Test Stand has been finished and the high gradient processing of the waveguide components has been started. Future plans include high gradient testing of various accelerating structures, including benchmark C-band accelerating cavity, a proton ß=0.5 cavity, and cavities made from different alloys. An upgrade to the facility is planned to allow for testing accelerator cavities at cryogenic temperatures. 		 
poster icon Poster MOPAB146 [3.778 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB146  
About • paper received ※ 17 May 2021       paper accepted ※ 26 May 2021       issue date ※ 19 August 2021  
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MOPAB341 First C-Band High Gradient Cavity Testing Results at LANL cavity, proton, GUI, operation 1057
 
  • E.I. Simakov, R.L. Fleming, D. Gorelov, T.A. Jankowski, M.F. Kirshner, J.W. Lewellen, J.D. Pizzolatto, M.E. Schneider, T. Tajima
    LANL, Los Alamos, New Mexico, USA
  • X. Lu, E.A. Nanni, S.G. Tantawi
    SLAC, Menlo Park, California, USA
  • M.E. Middendorf
    ANL, Lemont, Illinois, USA
  
  Funding: Los Alamos National Laboratory LDRD Program.
This poster will report the results of high gradient testing of the two proton β=0.5 C-band accelerating cavities. The cavities for proton acceleration were fabricated at SLAC and tested at high gradient C-band accelerator test stand at LANL. One cavity was made of copper, and the second was made of a copper-silver alloy. LANL test stand was constructed around a 50 MW, 5.712 GHz Canon klystron and is capable to provide power for conditioning single cell accelerating cavities for operation at surface electric fields up to 300 MV/m. These β=0.5 C-band cavities were the first two cavities tested on LANL C-band test stand. The presentation will report achieved gradients, breakdown probabilities, and other characteristics measured during the high power operation. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB341  
About • paper received ※ 19 May 2021       paper accepted ※ 25 May 2021       issue date ※ 30 August 2021  
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MOPAB342 Design, Fabrication, and Commissioning of the Mode Launchers for High Gradient C-Band Cavity Testing at LANL GUI, cavity, simulation, MMI 1060
 
  • E.I. Simakov, J.E. Acosta, D. Gorelov, M.F. Kirshner, J.W. Lewellen
    LANL, Los Alamos, New Mexico, USA
  • P. Borchard
    Dymenso LLC, San Francisco, USA
  • M.E. Schneider
    MSU, East Lansing, Michigan, USA
  
  Funding: Los Alamos National Laboratory LDRD Program.
This poster will report on the design, fabrication, and operation status of the new high gradient C-band TM01 mode launchers for the high gradient C-band test stand at LANL. Modern applications require accelerators with optimized cost of construction and operation, naturally calling for high-gradient acceleration. At LANL we commissioned a test stand powered by a 50 MW, 5.712 GHz Canon klystron. The test is capable of conditioning single cell accelerating cavities for operation at surface electric fields up to 300 MV/m. The rf field is coupled into the cavity from a WR187 waveguide through a mode launcher that converts the fundamental mode of the rectangular waveguide into the TM01 mode of the circular waveguide. Several designs for mode launchers were considered and the final design was chosen based on a compromise between the field enhancements, bandwidth, and simplicity and cost of fabrication. Four mode launchers were fabricated and cold-tested. Two mode launchers with the best transmission characteristics were installed and conditioned to high power. The presentation will report achieved gradients, breakdown probabilities, and other characteristics measured during operation. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB342  
About • paper received ※ 19 May 2021       paper accepted ※ 25 May 2021       issue date ※ 19 August 2021  
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MOPAB371 A Coupon Tester for Normal Conducting High-Gradient Materials cavity, coupling, vacuum, RF-structure 1147
 
  • J.W. Lewellen, D. Gorelov, D. Perez, E.I. Simakov
    LANL, Los Alamos, New Mexico, USA
  • M.E. Schneider
    Michigan State University, East Lansing, Michigan, USA
  
  Funding: Los Alamos National Laboratory LDRD Program
A coupon tester is an RF structure used to subject a material sample to very high RF fields, with the fields on the sample, or coupon, being higher than elsewhere in the cavity. To date, most such cavities were originally intended to explore the RF properties of superconducting materials, and can expose the sample to strong magnetic fields, but weak to no electric fields. As part of a program to develop materials and structures for high-gradient (> 100 MV/m), low-breakdown-rate normal-conducting accelerators, we have designed a C-band (5.712 GHz) cavity intended to subject samples to both magnetic and electric fields comparable to those experienced in high-gradient structure designs, using a TM-mode cavity; the electric and magnetic fields along the sample coupon can be directly compared to the fields on the iris of high-gradient structures. This poster will present the design criteria for our coupon tester cavity, nominal operating parameters, and our structure concept. The cavity design will be refined over the next several months, and will be constructed and in service near the start of 2022. 		 
poster icon Poster MOPAB371 [0.764 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB371  
About • paper received ※ 17 May 2021       paper accepted ※ 26 May 2021       issue date ※ 30 August 2021  
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TUPAB074 S-Band Transverse Deflecting Structure Design for CompactLight FEL, cavity, operation, impedance 1540
 
  • X.W. Wu, W. Wuensch
    CERN, Meyrin, Switzerland
  • S. Di Mitri
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  • N. Thompson
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  
  The CompactLight project is currently developing the design of a next generation hard X-ray FEL facility, which is based on high-gradient X-band (12 GHz) structures. However, to carry out pump-and-probe experiments in the project, two-bunch operation with a spacing of 10 X-band rf cycles is proposed. A sub-harmonic transverse deflecting structure working at S-band is proposed to direct the two bunches into two separate FEL lines. The two FEL pulses will have independently tunable wavelengths and can be combined in a single experiment with a temporal delay between pulses of ± 100 fs. The rf design of the transverse deflector is presented in this paper.  
poster icon Poster TUPAB074 [1.557 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB074  
About • paper received ※ 19 May 2021       paper accepted ※ 10 June 2021       issue date ※ 21 August 2021  
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TUPAB076 High-Gradient Breakdown Studies of an X-Band Accelerating Structure Operated in the Reversed Taper Direction linac, accelerating-gradient, linear-collider, collider 1543
 
  • X.W. Wu, N. Catalán Lasheras, A. Grudiev, G. McMonagle, I. Syratchev, W. Wuensch
    CERN, Meyrin, Switzerland
  • M. Boronat
    IFIC, Valencia, Spain
  • A. Castilla, A.V. Edwards, W.L. Millar
    Lancaster University, Lancaster, United Kingdom
  
  The results of high-gradient tests of a tapered X-band traveling-wave accelerator structure powered in reversed direction are presented. Powering the tapered structure from the small aperture, normally output, at the end of the structure provides unique conditions for the study of gradient limits. This allows high fields in the first cell for a comparatively low input power and a field distribution that rapidly falls off along the length of the structure. A maximum gradient of 130 MV/m in the first cell at a pulse length of 100 ns was reached for an input power of 31.9 MW. Details of the conditioning and operation at high-gradient are presented. Various breakdown rate measurements were conducted at different power levels and rf pulse widths. The structure was standard T24 CLIC test structure and was tested in Xbox-3 at CERN.  
poster icon Poster TUPAB076 [1.077 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB076  
About • paper received ※ 19 May 2021       paper accepted ※ 12 July 2021       issue date ※ 12 August 2021  
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TUPAB077 Novel Open Cavity for Rotating Mode SLED-Type RF Pulse Compressors cavity, coupling, GUI, linear-collider 1547
 
  • X.W. Wu, A. Grudiev
    CERN, Meyrin, Switzerland
  
  A new X-band high-power rotating mode SLAC Energy Doubler (SLED)-type rf pulse compressor is proposed. It is based on a novel cavity type, a single open bowl-shape energy storage cavity with high Q0 and compact size, which is coupled to the waveguide using a compact rotating mode launcher. The novel cavity type is applied to the rf pulse compression system of the main linac rf module of the klystron-based option of the Compact Linear Collider (CLIC). Quasi-spherical rotating modes of \rm{TE}1,2,4 and \rm{TE}1,2,13 are proposed for the correction cavity and storage cavity of the rf pulse compression system respectively. The storage cavity working at \rm{TE}1,2,13 has a Q0 of 240000 and a diameter less than 33 cm. The design of the pulse compressor and in particular of the high-Q cavity will be presented in detail.  
poster icon Poster TUPAB077 [1.229 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB077  
About • paper received ※ 19 May 2021       paper accepted ※ 10 June 2021       issue date ※ 27 August 2021  
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TUPAB083 Dual Energies in the LCLS Copper Linac linac, quadrupole, feedback, betatron 1570
 
  • F.-J. Decker, C. Bianchini Mattison, D.K. Bohler, A. Brachmann, W.S. Colocho, S. Condamoor, M.L. Gibbs, K.H. Kim, A.A. Lutman, T.J. Maxwell, J.A. Mock, H.-D. Nuhn, J.C. Sheppard, H. Smith, T.J. Smith, M. Stanek, S. Zelazny, Z. Zhang, C.M. Zimmer
    SLAC, Menlo Park, California, USA
  
  For LCLS-II two undulators were installed at SLAC, one for soft and one for hard x-rays. Before the superconducting linac gets turned on the copper linac is providing beams at 120 Hz to these two beam destinations. The 120 Hz can be split in many different ratios between soft and hard via a pulsed magnet. To get an optimized beam for the quite different photon energies the pulsed linac components like modulators and RF can provide many different beam parameters, mainly energies and bunch lengths for the two undulator lines. How this was implemented with timing setups of triggers and finally after the split the necessary matching of the transverse phase space will be discussed.  
poster icon Poster TUPAB083 [0.479 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB083  
About • paper received ※ 19 May 2021       paper accepted ※ 27 May 2021       issue date ※ 21 August 2021  
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TUPAB110 Measurement and Correction of RF Kicks in the LCLS Accelerator to Improve Two-Bunch Operation electron, FEL, cavity, experiment 1644
 
  • R.A. Margraf, F.-J. Decker, Z. Huang, G. Marcus
    SLAC, Menlo Park, California, USA
  • Z. Huang
    Stanford University, Stanford, California, USA
  
  Funding: This work was supported by the Department of Energy, Laboratory Directed Research and Development program at SLAC National Accelerator Laboratory, under contract DE-AC02-76SF00515.
RF kicks, caused by a misalignment of an electron beam and acceleration structure, produce an electron orbit in the accelerator which decreases the final energy of the accelerated electron beam and is detrimental to lasing electron bunches in an X-ray Free Electron Laser (XFEL). RF kicks can depend on the RF waveform of the accelerating structure, so controlling this effect is particularly important when two or more electron bunches are accelerated within an RF fill time. Multibunch modes have been successfully developed for the Linac Coherent Light Source (LCLS) accelerator at SLAC,* and are being continually improved to accommodate new experiments. One such experiment, the Cavity-Based XFEL (CBXFEL)** project will require two electron bunches separated by 218.5 ns which must be identical in energy and orbit. To reduce variation in energy and orbit between the two bunches, we studied the RF kicks produced by each of 75 accelerator segments in the LCLS linac at several RF timings. Here, we discuss these measurements and propose a method to correct RF kicks in the LCLS accelerator using corrector dipoles and quadrupoles.
* F.-J. Decker, et al. Recent Developments and Plans for Two Bunch Operation, Proc. of FEL2017, TUP023.
** Gabriel Marcus et al. CBXFEL Physics Requirements Document. SLAC-I-120-103-121-00. 2020. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB110  
About • paper received ※ 19 May 2021       paper accepted ※ 15 June 2021       issue date ※ 29 August 2021  
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TUPAB199 Progress on the Proton Power Upgrade at the Spallation Neutron Source target, linac, cryomodule, proton 1876
 
  • M.S. Champion, C.N. Barbier, M.S. Connell, J. Galambos, M.P. Howell, S.-H. Kim, J.S. Moss, B.W. Riemer, K.S. White
    ORNL, Oak Ridge, Tennessee, USA
  • E. Daly
    JLab, Newport News, Virginia, USA
  • N.J. Evans, G.D. Johns
    ORNL RAD, Oak Ridge, Tennessee, USA
  
  Funding: ORNL is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. This research was supported by the DOE Office of Science, Basic Energy Science.
The Proton Power Upgrade Project at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory will double the proton power capability from 1.4 to 2.8 MW. This will be accomplished through an energy increase from 1.0 to 1.3 GeV and a beam current increase from 26 to 38 mA. The energy increase will be accomplished through the addition of 7 cryomodules to the linear accelerator (Linac). The beam current increase will be supported by upgrading several radio-frequency systems in the normal-conducting section of the Linac. Upgrades to the accumulator ring injection and extraction regions will accommodate the increase in beam energy. A new 2-MW-capable target and supporting systems will be developed and installed. Conventional facility upgrades include build-out of the existing klystron gallery and construction of a tunnel stub to facilitate future beam transport to the second target station. The project received approval to proceed with construction in October 2020. Procurements are in progress, and some installation activities have already occurred. Most of the installation will take place during three outages in 2022-2023. The project early finish is planned for 2025. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB199  
About • paper received ※ 10 May 2021       paper accepted ※ 28 May 2021       issue date ※ 21 August 2021  
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TUPAB296 LLRF Upgrade at the Argonne Wakefield Accelerator Test Facility LLRF, laser, controls, pick-up 2176
 
  • W. Liu, D.S. Doran, G. Ha, P. Piot, J.G. Power, J.H. Shao, C. Whiteford, E.E. Wisniewski
    ANL, Lemont, Illinois, USA
  • L.R. Doolittle, D. Filippetto, D. Li, S. Paiagua, C. Serrano, V.K. Vytla
    LBNL, Berkeley, California, USA
  
  Funding: US Department of Energy, Office of Science
The Argonne Wakefiled Accelerator (AWA) Test Facility designed and operated a homemade LLRF system for the last 20 years. It is based on NI-PXI products that has now become obsolete. The AWA’s LLRF cannot keep up with the increasing stability demands of AWA’s upgraded facility. An overhaul of the system is strongly desired. With the support from DOE-HEP, the AWA is collaborating with Lawrence Berkeley National Laboratory (LBNL)to upgrade its LLRF system with modern instrumentation to meet the growing stability demands. An overview of AWA’s current LLRF system performance is presented together with the upgrade plan and expectations. 		 
poster icon Poster TUPAB296 [1.943 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB296  
About • paper received ※ 19 May 2021       paper accepted ※ 05 July 2021       issue date ※ 26 August 2021  
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TUPAB349 High Efficiency, Low Cost RF Sources for Accelerators and Colliders cavity, controls, simulation, electron 2322
 
  • R.L. Ives, T. Bui, G. Collins, H. Freund, T.W. Habermann, D. Marsden, M.E. Read
    CCR, San Mateo, California, USA
  • B.E. Chase, J. Reid
    Fermilab, Batavia, Illinois, USA
  • N. Chaudhary, J.R. Conant, T. Cox, R. Ho, C. McVey, C.M. Walker
    CPI, Palo Alto, California, USA
  • J.C. Frisch, L. Ma
    SLAC, Menlo Park, California, USA
  • A. Jensen
    Leidos Corp, Billerica, MA, USA
  • J.M. Potter
    JP Accelerator Works, Los Alamos, New Mexico, USA
  • W. Sessions
    Georgia Tech Research Institute, Smyrna, Georgia, USA
  
  Funding: U.S. Department of Energy
Calabazas Creek Research, Inc. (CCR) and its collaborators are developing high efficiency, low cost RF sources. Phase and Amplitude Controlled Magnetrons: CCR, Fermilab, and Communications & Power Industries, LLC (CPI) recently developed a 100 kW, 1.3 GHz magnetron system with amplitude and phase control. The system operated at more than 80% efficiency and demonstrated rapid control of amplitude and phase. Multiple Beam Triodes: CCR, in collaboration with CPI and JP Accelerator Works, Inc., is developing 200 kW, pulsed and CW RF sources from 350 to 700 MHz with projected efficiencies exceeding 80% and cost of $0.50/Watt. Prototype tubes are scheduled for tests in spring 2021. High Efficiency Klystrons:CCR, CPI, and Leidos, Inc. are building a 1.3 GHz, 100 kW klystron operating at 80% efficiency. High power testing is scheduled for summer 2021. Multiple Beam IOTs: CCR and Georgia Tech Research Institute are developing MBIOTs with simplified input coupling and high efficiency. Simulations indicate that 3rd harmonic drive power can increase the efficiency 8-10 %. The program is developing a prototype tube to produce 200 kW peak, 100 kW average power at 704 MHz. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB349  
About • paper received ※ 18 May 2021       paper accepted ※ 01 June 2021       issue date ※ 27 August 2021  
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TUPAB354 352-MHz Solid State RF System Development at the Advanced Photon Source cavity, GUI, controls, PLC 2335
 
  • D. Horan, D.J. Bromberek, N.P. DiMonte, A. Goel, T.J. Madden, A. Nassiri, G. Trento, G.J. Waldschmidt
    ANL, Lemont, Illinois, USA
  
  Development effort is underway on a 352MHz, 200kW solid state rf system intended as the base design to replace the existing klystron-based rf systems presently in use at the Advanced Photon Source (APS). A sixteen-input, 200kW final combining cavity was designed, built, and successfully tested to 29kW CW in combiner mode, and to 200kW CW in back-feed mode, where an external klystron was used to transmit power into the combining cavity. A four-port waveguide combiner was also tested in both backfeed and combiner mode to 193kW and 26kW respectively. Slow and fast interlock systems were designed and implemented to support the testing process. An EPICS and Programmable Logic Controller (PLC)-based system was developed to control, communicate with, and monitor the rf amplifiers used in the combiner-mode test, and to monitor and log system performance parameters relating to the combining cavity. Low-level rf control of the cavity in 29kW combiner-mode operation was achieved using the existing APS analog low-level rf hardware. Test data and design details are presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB354  
About • paper received ※ 18 May 2021       paper accepted ※ 31 May 2021       issue date ※ 19 August 2021  
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TUPAB356 Electron Beam Driven Cavities electron, cavity, simulation, linac 2342
 
  • M. Schuett, U. Ratzinger
    IAP, Frankfurt am Main, Germany
  
  State of the art high power feeder for RF cavities used as accelerators generally require RF amplifiers consisting of a vacuum tube, such as a klystron or Grid Tubes. In addition, a number of cost intensive RF auxiliary devices are needed: Modulator, waveguides, circulator, power dump and couplers. The equipment requires significant floor space within the linac building. Alternatively, we propose a direct driven system. Aμbunched electron beam is injected directly into the cavity. A high perveance bunched electron beam can be generated by a standard electron gun combined with a deflecting beam chopper*, an off-the-shelf IOT or klystron, respectively. The pulse rate is determined by the resonance frequency of the cavity. The resonator hereby acts like the output cavity of a klystron: Within its propagation through the cavity the beam is decelerated increasing the stored energy of the accelerator. We present 3D particle PIC simulations evaluating the geometry and beam properties in order to optimize the coupling efficiency and cavity excitation of state-of-art CH particle accelerator structures.
* S. Setzer, T. Weiland and U. Ratzinger, A Chopped Electron Beam Driver for H-Type Cavities, 20th ‘International Linac Conference, Monterey, California, August 21-25, 2000, pp. 1001-1003 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB356  
About • paper received ※ 19 May 2021       paper accepted ※ 21 June 2021       issue date ※ 11 August 2021  
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WEPAB038 Commissioning of a New X-Band, Low-Noise LLRF System LLRF, cavity, MMI, linac 2683
 
  • A.V. Edwards, M. Boronat Arevalo, N. Catalán Lasheras, G. McMonagle
    CERN, Meyrin, Switzerland
  • A.C. Dexter
    Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
  
  To increase beam energy in the CLEAR facility at CERN and study the CLIC accelerating structure prototype in operating conditions, the first X-band test facility at CERN was upgraded in 2020. Both, the acquisition and software systems at X-band test stand 1 (Xbox1) were upgraded to exhibit low phase noise which is relevant to klystron based CLIC and to the use of crab cavities in the beam delivery system. The new LLRF uses down-conversion which necessitates a local oscillator which can be produced by two different methods. The first is a PLL, a commonly used technique which has been previously employed at the other X-band facilities at CERN. The second is a novel application of a single sideband up-convertor. The up-convertor system has demonstrated reduced phase noise when compared with the PLL. The commissioning of the new system began in late 2020 with the conditioning of a 50 MW Klystron. Measurements of the quality of the new LLRF will be shown. These will compare the PLL and up-convertor with particular attention on the quality of the phase measurements. Also, a preliminary study of phase shifts in the waveguide network due to temperature changes will be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB038  
About • paper received ※ 13 May 2021       paper accepted ※ 05 July 2021       issue date ※ 20 August 2021  
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WEPAB042 Linac-200: A New Electron Test Beam Facility at JINR electron, controls, linac, gun 2697
 
  • M.A. Nozdrin, M. Gostkin, V. Kobets, Y.A. Samofalova, G. Shirkov, A. Trifonov, K. Yunenko, A. Zhemchugov
    JINR, Dubna, Moscow Region, Russia
  
  Commissioning of a new electron test beam facility Linac-200 comes to the end at JINR (Dubna, Russia). The core of the facility is a refurbished MEA accelerator from NIKHEF. The key accelerator subsystems including controls, vacuum, precise temperature regulation were redesigned or deeply upgraded. The facility provides electron beams with energy up to 200 MeV while the beam current varying smoothly from 40 mA down to almost zero (single electrons in a bunch). The main goal of the facility is providing test beams for particle detector R&D, studies of novel approaches to the beam diagnostics, and education and training of graduate and postgraduate students. The current status and operation parameters of the facility will be reported.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB042  
About • paper received ※ 18 May 2021       paper accepted ※ 23 June 2021       issue date ※ 23 August 2021  
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WEPAB045 European XFEL High-Power RF System - the First 4 Years of Operation operation, FEL, GUI, electron 2708
 
  • M. Bousonville, S. Choroba, T. Grevsmühl, S. Göller, A. Hauberg, V.V. Katalev, K. Machau, V. Vogel, B. Yildirim
    DESY, Hamburg, Germany
  
  In 2016, the installation of the European XFEL was completed and its 26 RF stations started operation in 2017. Each RF station consists of a 10 MW-1.3 GHz-multibeam klystron, a HV pulse modulator and a waveguide system to supply the superconducting cavities and the normal-conducting electron gun with RF power. During commissioning and subsequent operation, the RF stations were closely monitored and causes of failures were investigated. For the optimisation of the RF systems, the various RF station failures were evaluated according to their impact on accelerator operation and the measures to eliminate them were prioritised accordingly. This report describes the operation experience and improvements of the high-power RF stations during the first 4 years of operation.  
poster icon Poster WEPAB045 [6.887 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB045  
About • paper received ※ 19 May 2021       paper accepted ※ 07 June 2021       issue date ※ 21 August 2021  
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WEPAB073 An Overview of the Radio-Frequency System for an Inverse Compton X-Ray Source Based on CLIC Technology LLRF, controls, network, laser 2759
 
  • T.G. Lucas, O.J. Luiten, P.H.A. Mutsaers, X.F.D. Stragier, H.A. Van Doorn, F.M. van Setten, H.J.M. van den Heuvel, M.L.M.C. van der Sluis
    TUE, Eindhoven, The Netherlands
  
  Funding: This project is financed by the "Interreg V programme Flanders-Netherlands" with financial support of the European Fund for Regional Development.
Compact inverse Compton scattering X-ray sources are gaining in popularity as the future of lab-based x-ray sources. Smart*Light is one such facility, under commissioning at Eindhoven University of Technology (TU/e), which is based on high gradient X-band technology originally designed for the Compact Linear Collider (CLIC) and its test stands located at CERN. Critical to the beam quality is the RF system which aims to deliver 10-24 MW RF pulses at repetition rates up to 1 kHz with a high amplitude and phase stability of <0.5\% and <0.65~° allowing it to adhere to strict synchronicity conditions at the interaction point. This work overviews the design of the high power and low level RF systems for Smart*Light. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB073  
About • paper received ※ 19 May 2021       paper accepted ※ 23 June 2021       issue date ※ 29 August 2021  
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WEPAB150 Monotron Beam Break Up Instability Analysis HOM, cavity, dipole, resonance 2968
 
  • V. Volkov, V.M. Petrov
    BINP SB RAS, Novosibirsk, Russia
  
  New features of monotron beam break up (BBU) instability such as the typing of high order monopole modes (HOMs)in each cavity by two classes one of them are stable and other ones are unstable, HOM effective quality factor depending on average beam current, and normalized invariable threshold current individually characterizes each HOM are investigated in this article in detail.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB150  
About • paper received ※ 19 May 2021       paper accepted ※ 09 June 2021       issue date ※ 31 August 2021  
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WEPAB296 A Klystron Phase Lock Loop for RF System at TPS Booster Ring controls, cathode, LLRF, injection 3354
 
  • F.Y. Chang, M.H. Chang, S.W. Chang, L.J. Chen, F.-T. Chung, Y.D. Li, M.-C. Lin, Z.K. Liu, C.H. Lo, Ch. Wang, M.-S. Yeh, T.-C. Yu
    NSRRC, Hsinchu, Taiwan
  
  In TPS booster ring, the DLLRF is used to controlled the ramping gap voltage and also the energy saving module is applied to save power while the ring does not inject beam. But we occurred to have a problem of PI saturation due to a large phase change when the energy saving module working. The energy saving module switches the anode voltage of the klystron from high to low level to decrease the cathode current while the ring does not inject and do the opposite while the ring injects. This action causes a large phase change of the transmitter and leads the PI controller to work in the wrong direction. We add a klystron phase loop to solve this situation.  
poster icon Poster WEPAB296 [0.792 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB296  
About • paper received ※ 19 May 2021       paper accepted ※ 01 July 2021       issue date ※ 30 August 2021  
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WEPAB301 Design of an X-Band LLRF System for TEX Test Facility at LNF-INFN LLRF, cavity, insertion, GUI 3371
 
  • L. Piersanti, D. Alesini, M. Bellaveglia, S. Bini, B. Buonomo, F. Cardelli, C. Di Giulio, M. Diomede, A. Falone, G. Franzini, A. Gallo, A. Liedl, S. Pioli, S. Quaglia, L. Sabbatini, M. Scampati, G. Scarselletta, A. Stella
    INFN/LNF, Frascati, Italy
  
  Funding: Latino is a project co-funded by Regione Lazio within POR-FESR 2014-2020 program
In the framework of LATINO project (Laboratory in Advanced Technologies for INnOvation) funded by Lazio regional government, a TEst stand for X-band (TEX) is being commissioned at Frascati National Laboratories (LNF) of INFN. TEX is born as a collaboration with CERN, aimed at carrying out high power tests of X-band accelerating structure prototypes and waveguide components, and it is of paramount importance in view of the construction of EuPRAXIA@SPARC_LAB facility at LNF. In order to generate, manipulate and measure the RF pulses needed to feed the RF power unit (solid state ScandiNova K400 modulator, CPI 50 MW 50 Hz klystron) an X-band low level RF system has been developed, making use of a commercial S-band (2.856 GHz) Libera digital LLRF (manufactured by Instrumentation Technologies) with a newly designed up/down conversion stage and a reference generation/distribution system, which is able to produce coherent reference frequencies for the American S-band (2.856 GHz) and European X-band (11.994 GHz). In this paper the main features of such systems will be reviewed together with preliminary laboratory measurement results. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB301  
About • paper received ※ 19 May 2021       paper accepted ※ 12 July 2021       issue date ※ 27 August 2021  
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WEPAB314 TEX - an X-Band Test Facility at INFN-LNF controls, GUI, LLRF, framework 3406
 
  • S. Pioli, D. Alesini, F.A. Anelli, M. Bellaveglia, S. Bini, B. Buonomo, S. Cantarella, F. Cardelli, G. Catuscelli, R. Ceccarelli, A. Cecchinelli, F. Chiarelli, P. Ciuffetti, R. Clementi, C. Di Giulio, E. Di Pasquale, G. Di Raddo, M. Diomede, A. Esposito, L. Faillace, A. Falone, G. Franzini, A. Gallo, S. Incremona, A. Liedl, D. Pellegrini, G. Piermarini, L. Piersanti, S. Quaglia, R. Ricci, L. Sabbatini, M. Scampati, G. Scarselletta, A. Stella, R. Zarlenga
    INFN/LNF, Frascati, Italy
  
  Funding: The LATINO project is co-funded by the Regione Lazio within POR-FESR 2014-2020 European activities (public call "Open Research Infrastructures").
We report the status of the development of an High Power RF Laboratory in X-Band called TEX (TEst-stand for X-Band). TEX is part of the LATINO (Laboratory in Advanced Technologies for INnOvation) initiative that is ongoing at the Frascati National Laboratories (LNF) of the Italian Institute for Nuclear Physics (INFN) that covers many different areas focused on particle accelerator technologies. TEX is a RF test facility based on solid-state K400 modulator from ScandiNova with a 50MW class X-band (11.996 GHz) klystron tube model vkx 8311a operating at 50 Hz. This RF source will operate as resource for test and research programs such as the RF breakdown on RF waveguide components as well as high power testing of accelerating structures for future high gradient linear accelerator such as EuPRAXIA and CLIC. The high power testing will be performed in a dedicated brand-new bunker that has been recently built. RF system, vacuum controls and safety equipments are currently being installed. The first accelerating structure testing is scheduled by beginning 2022. In this document design and tests for all the sub-systems of the facility will be presented and discussed. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB314  
About • paper received ※ 19 May 2021       paper accepted ※ 28 July 2021       issue date ※ 19 August 2021  
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WEPAB374 The Southern Hemisphere’s First X-Band Radio-Frequency Test Facility at the University of Melbourne electron, gun, network, GUI 3588
 
  • M. Volpi, R.P. Rassool, S.L. Sheehy, G. Taylor, S.D. Williams
    The University of Melbourne, Melbourne, Victoria, Australia
  • M.J. Boland
    CLS, Saskatoon, Saskatchewan, Canada
  • M.J. Boland
    University of Saskatchewan, Saskatoon, Canada
  • N. Catalán Lasheras, S. Gonzalez Anton, G. McMonagle, S. Stapnes, W. Wuensch
    CERN, Meyrin, Switzerland
  • R.T. Dowd, K. Zingre
    AS - ANSTO, Clayton, Australia
  
  The first Southern Hemisphere X-band Laboratory for Accelerators and Beams (X-LAB) is under construction at the University of Melbourne, and it will operate CERN X-band test stand containing two 12GHz 6MW klystron amplifiers. By power combination through hybrid couplers and the use of pulse compressors, up to 50 MW of peak power can be sent to any of 2 test slots at pulse repetition rates up to 400 Hz. The test stand is dedicated to RF conditioning and testing CLIC’s high gradient accelerating structures beyond 100 MV/m. It will also form the basis for developing a compact accelerator for medical applications, such as radiotherapy and compact light sources. Australian researchers working as part of a collaboration between the University of Melbourne, international universities, national industries, the Australian Synchrotron -ANSTO, Canadian Light Source and the CERN believe that creating a laboratory for novel accelerator research in Australia could drive technological and medical innovation.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB374  
About • paper received ※ 18 May 2021       paper accepted ※ 06 July 2021       issue date ※ 30 August 2021  
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THXC07 Adaptive Control of Klystron Operation Parameters for Energy Saving at Storage Ring of TPS operation, controls, cathode, storage-ring 3748
 
  • T.-C. Yu, F.Y. Chang, M.H. Chang, S.W. Chang, L.J. Chen, F.-T. Chung, Y.D. Li, M.-C. Lin, Z.K. Liu, C.H. Lo, Ch. Wang, M.-S. Yeh
    NSRRC, Hsinchu, Taiwan
  
  To satisfy maximum beam current operation in the storage ring of TPS, the operation parameters of both RF transmitters are set to be able to generate its maxi-mum RF power in daily usage. Under such condition, the klystrons can deliver any power below 300kW at constant AC power consumption which is about 520-530 kW. Hence, the AC power usage is independent of the required RF output power. To best utilize the avail-able AC power based on the required RF power, an adaptive control methodology is proposed here to change the operation parameters of the klystron, cath-ode voltage and anode voltage, according to the pre-sent RF power. The corresponding operation parame-ters are applied by the prior tested table which maps the operation parameters with the different saturation RF power. The test results show that the saved energy can be 32% to 11% from 30mA to 450mA for both RF plants as comparing to constant operation parameters of 1047 kW AC power.  
slides icon Slides THXC07 [1.241 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THXC07  
About • paper received ※ 19 May 2021       paper accepted ※ 06 July 2021       issue date ※ 11 August 2021  
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THPAB113 The Extended Operative Range of the LNF LINAC and BTF Facilities linac, experiment, positron, target 3987
 
  • L.G. Foggetta, M. Belli, B. Buonomo, F. Cardelli, R. Ceccarelli, A. Cecchinelli, R. Clementi, D. Di Giovenale, C. Di Giulio, G. Piermarini, L.A. Rossi, S. Strabioli, R. Zarlenga
    INFN/LNF, Frascati, Italy
  
  Funding: These activities has been partially supported by AIDA-2020 Grant Agreement 654168 and ERAD projects.
In 2020 the INFN-LNF LINAC and BTF have performed long-term runs for test beams and fixed-target experiments. The scientific needs of these items have been leading our groups to continuous improvements of the LINAC operative range both in pulse time at maximum energy and on the minimum transported energy, until the reset to DAΦNE injections at the beginning of 2021. We will also show the BTF recent developments in the transported beams and the second line installation. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB113  
About • paper received ※ 19 May 2021       paper accepted ※ 27 July 2021       issue date ※ 27 August 2021  
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THPAB252 Machine Learning for Improved Availability of the SNS Klystron High Voltage Converter Modulators operation, controls, real-time, high-voltage 4303
 
  • G.C. Pappas
    ORNL RAD, Oak Ridge, Tennessee, USA
  • D. Lu
    ORNL, Oak Ridge, Tennessee, USA
  • M. Schram
    JLab, Newport News, Virginia, USA
  • D.L. Vrabie
    PNNL, Richland, Washington, USA
  
  Funding: SNS/ORNL is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy
Beam availability has increased at the SNS, however, the targeted availability is greater than 95 %, while the SNS has failed to meet lower targets in the past. The HVCM used to power the linac klystrons have been one source of lost beam time and was chosen to explore using AI/ML techniques to improve reliability. Among the possibilities being explored are automating the tuning of HVCMs and predicting component failures such as capacitor aging, rectifier assemblies containing hundreds of diodes, and insulating oil degradation. The methodology pursued includes data cleaning, de-noising, post-analysis data labeling, and machine learning model development. We explore using Long Short-Term Memory and autoencoders for anomaly detection and prognostication used to schedule maintenance. We evaluate the use of model regularizers and constraints to improve the performance of the model and investigate methods to estimate the uncertainty of the models to provide a robust prediction with statistical interoperability. This paper describes the operational experience and known failures of the HVCMs and the proposed ML methodology and the preliminary results of training the AI/ML algorithms.
* G. Dodson, Approach to Reliable Operations, 26-DodsonApproach to Reliable Operation-r1.pdf, Feb., 2010. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB252  
About • paper received ※ 18 May 2021       paper accepted ※ 14 July 2021       issue date ※ 29 August 2021  
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THPAB296 The Spallation Neutron Source Normal Conducting Linac RF System Design for the Proton Power Upgrade Project DTL, cavity, GUI, linac 4383
 
  • J.S. Moss, M.T. Crofford, S.W. Lee, G.D. Toby
    ORNL, Oak Ridge, Tennessee, USA
  • M.E. Middendorf
    ORNL RAD, Oak Ridge, Tennessee, USA
  
  Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract number DE-AC05-00OR22725.
The Proton Power Upgrade (PPU) project at the Spallation Neutron Source will double the available proton beam power from 1.4 to 2.8 MW by increasing the beam energy from 1.0 to 1.3 GeV and the beam current from 26 to 38 mA. The increase in beam current resulted in the need to redesign the existing normal conducting linac (NCL) RF Systems. High-power testing of the existing NCL RF Systems configured to accelerate PPU-level beam provided the data used to make the final design decisions. This paper describes the development and execution of those in-situ tests and the subsequent results. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB296  
About • paper received ※ 17 May 2021       paper accepted ※ 22 July 2021       issue date ※ 20 August 2021  
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THPAB310 Automatic Correction System for the TLS Booster Linac Klystron Modulator electron, booster, acceleration, linac 4396
 
  • S.J. Huang, Y.K. Lin
    NSRRC, Hsinchu, Taiwan
  
  The aim of this article is to analyse the performance output of the klystron modulator, which is based on the observation of the output voltage and current performance of the linear-accelerator klystron modulator; we modify the operating-point parameters based on those results or assess whether the klystron needs to be replaced. For this purpose, we collect the observation data of the klystron performance; we then develop a program to adjust automatically the high-voltage setting of the klystron to ensure that the storage current maintains beam current 360 mA in the top-up mode operation.  
poster icon Poster THPAB310 [0.785 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB310  
About • paper received ※ 16 May 2021       paper accepted ※ 02 July 2021       issue date ※ 13 August 2021  
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THPAB369 Research and Design of an X-Band 100-MeV Compact Electron Accelerator for Very High Energy Electron Therapy in Tsinghua University cavity, electron, gun, linac 4502
 
  • X. Lin, H.B. Chen, J. Shi, C.-X. Tang, H. Zha, L.Y. Zhou
    TUB, Beijing, People’s Republic of China
  
  A 100-MeV Compact Electron Accelerator scheme based on the Tsinghua X-band (11.424 GHz) High Power Test stand (TPot-X) was proposed for Very High Energy Electron (VHEE) radiotherapy. A pulse compressor with correction cavity chain was designed to compress the 50 MW, 1500 ns microwave pulse from the X-band klystron to 120 MW, 300 ns. The acceleration system consists of 3 parts, a buncher which bunches and boosts the electron from a thermionic cathode gun to 8 MeV, and two accelerating structure which further boost the electron energy to 100MeV. The detailed design and consideration are presented in this article.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB369  
About • paper received ※ 19 May 2021       paper accepted ※ 01 July 2021       issue date ※ 14 August 2021  
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FRXB02 Development of 36 GHz RF Systems for RF Linearisers cavity, HOM, linac, impedance 4518
 
  • A. Castilla, G. Burt
    Lancaster University, Lancaster, United Kingdom
  • M. Behtouei, B. Spataro
    INFN/LNF, Frascati, Italy
  • G. Burt
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • J.C. Cai, A. Castilla, A. Latina, X. Liu, I. Syratchev, X.W. Wu, W. Wuensch
    CERN, Geneva, Switzerland
  • J.C. Cai, A. Castilla
    Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
  • A.W. Cross, L. Zhang
    USTRAT/SUPA, Glasgow, United Kingdom
  • L.J.R. Nix
    University of Strathclyde, Glasgow, United Kingdom
  
  Funding: This project has received funding from the European Union’s Horizon2020 research and innovation programme under grant agreement No 777431.
As part of the deign studies, the CompactLight project plans to use an injector in the C-band. Which constitutes a particular complication for the harmonic system in charge of linearising the beam’s phase space, since it means its operation frequency could be higher than the standard X-band RF technologies. In the present work, we investigated a 36 GHz (Ka-band) as the ideal frequency for the harmonic system. A set of structure designs are presented as candidates for the lineariser, based on different powering schemes and pulse compressor technologies. The comparison is made both in terms of beam dynamics and RF performance. Given the phase stability requirements for the MW class RF sources needed for this system, we performed careful studies of a Gyro-Klystron and a multi-beam klystron as potential RF sources, with both showing up to 3 MW available power using moderate modulator voltages. Alternatives for pulse compression at Ka-band are also discussed in this work. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-FRXB02  
About • paper received ※ 17 May 2021       paper accepted ※ 19 July 2021       issue date ※ 25 August 2021  
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