Keyword: cavity
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MOPOST005 The HL-LHC Project Gets Ready for Its Deployment operation, luminosity, civil-engineering, collimation 50
 
  • M. Zerlauth, O.S. Brüning, B. Di Girolamo, P. Fessia, C. Gaignant, H. Garcia Gavela, E.H. Maclean, M. Modena, Th. Otto, L.J. Tavian, G. Vandoni
    CERN, Meyrin, Switzerland
 
  Following the successful completion of the second long shutdown (LS2), the Large Hadron Collider (LHC) is preparing for its final operational run before the majority of the High Luminosity Upgrade (HL-LHC) will be installed during the third Long Shutdown starting in 2026. The HL-LHC upgrade will enable a further tenfold increase in integrated luminosity delivered to the ATLAS and CMS experiments, starting by an upgrade of the machine protection, collimation and shielding systems in LS2, and followed by the deployment of novel key technologies, including Nb3Sn based insertion region magnets, cold powering by MgB2 superconducting links and integration of Nb crab-cavities to compensate the effects of a larger crossing angle. After a period of intensive R&D and prototyping, the project is now entering the phase of industrialization and series production for all main components. In this contribution, we provide an overview of the project status and plans for deployment and performance ramp-up. Progress on the validation of key technologies, status of prototypes and series production as well as the final integration studies for the HL equipment are summarized. These are accompanied by the imminent completion of major civil engineering work and the start of infrastructure installations. Initial operational experience will be gained at the Inner Triplet (IT) String, presently in assembly at CERN’s Superconducting Magnet Test Facility, which will enable a fully integrated test of the main magnets, powering, and protection systems in the actual HL-LHC insertion configuration.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST005  
About • Received ※ 08 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 18 June 2022
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MOPOST007 Summary of the First Fully Operational Run of LINAC4 at CERN linac, MMI, operation, injection 58
 
  • P.K. Skowroński, G. Bellodi, B. Bielawski, R.B. Borner, G.P. Di Giovanni, E. Gousiou, J.-B. Lallement, A.M. Lombardi, B. Mikulec, J. Parra-Lopez, F. Roncarolo, J.L. Sanchez Alvarez, R. Scrivens, L. Timeo, R. Wegner
    CERN, Meyrin, Switzerland
 
  In December 2020 the newly commissioned LINAC4 started delivering beam for the CERN proton accelerator chain, replacing the old LINAC2. LINAC4 is a 352 MHz normal conducting linac, providing a beam of negative hydrogen ions at 160 MeV that are converted into protons at injection into the PS Booster synchrotron. In this paper we report on the achieved beam performance, availability, reproducibility and other operational aspects of LINAC4 during its first fully operational year. We also present the machine developments performed and the plans for future improvements.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST007  
About • Received ※ 09 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 04 July 2022
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MOPOST009 EIC Crab Cavity Multipole Analysis and Their Effects on Dynamic Aperture multipole, dynamic-aperture, luminosity, collider 66
 
  • Q. Wu, B.P. Xiao
    BNL, Upton, New York, USA
  • S.U. De Silva
    ODU, Norfolk, Virginia, USA
  • Z. Li
    SLAC, Menlo Park, California, USA
  • Y. Luo
    Brookhaven National Laboratory (BNL), Electron-Ion Collider, Upton, New York, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
Crab cavity is essential for retrieving the loss in luminosity due to the large crossing angle in the two colliding beam lines of the Electron Ion Collider (EIC). Due to the asymmetric design of the proton beam crab cavity, the fundamental mode consists of contributions from higher order multipoles. These multipole modes may change during fabrication and installation of the cavities, and therefore affect the local dynamic aperture. Thresholds for each order of the multipoles are applied to ensure dynamic aperture requirements at these crab cavities. In this paper, we analyzed the strength of the multipoles due to fabrication and installation accuracies, and set limitations to each procedure to maintain the dynamic aperture requirement.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST009  
About • Received ※ 06 June 2022 — Revised ※ 17 June 2022 — Accepted ※ 22 June 2022 — Issue date ※ 10 July 2022
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MOPOST010 Deuteron Beam Power Ramp-Up at SPIRAL2 linac, MEBT, MMI, LEBT 70
 
  • A.K. Orduz, M. Di Giacomo, R. Ferdinand, J.-M. Lagniel, G. Normand
    GANIL, Caen, France
  • D.U. Uriot
    CEA-IRFU, Gif-sur-Yvette, France
 
  The SPIRAL2 linac commissioning started on 8 July 2019 after obtaining the authorisation to operate by the French Safety Authority. The tuning of the two Low Energy Beam Transport (LEBT), Radio Frequency Quadrupole (RFQ), Medium Energy Beam Transport (MEBT), Superconducting (SC) linac and High Energy Beam Transport (HEBT) was done with H+, 4He2+ and D+ beams during three periods of six months each in 2019, 2020 and 2021. The results obtained in 2021 with a D+ beam are presented. The strategy for the tuning of the MEBT, including three rebunchers, is described. The comparison between the beam parameter measurements and reference simulations are also presented. The main results of the power ramp-up to 10 kW in the linac with a 5 mA D+ beam are next reported. Finally, the extrapolation from the nominal power (200 kW) to the obtained results is analysed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST010  
About • Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 18 June 2022
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MOPOST011 CEA Contribution to the PIP-II Linear Accelerator cryomodule, SRF, vacuum, linac 74
 
  • N. Bazin, J. Belorgey, S. Berry, J. Drant, O. Napoly, A. Raut, P. Sahuquet, C. Simon
    CEA-DRF-IRFU, France
  • S. Arsenyev, Q. Bertrand, P. Brédy, E. Cenni, C. Cloué, R. Cubizolles, H. Jenhani, S. Ladegaillerie, A. Le Baut, A. Moreau, O. Piquet
    CEA-IRFU, Gif-sur-Yvette, France
  • O. Napoly
    Fermilab, Batavia, Illinois, USA
 
  The Proton Improvement Plan II (PIP-II) that will be installed at Fermilab is the first U.S. accelerator project that will have significant contributions from international partners. CEA joined the international collaboration in 2018, and will deliver 10 low-beta cryomodules as In-Kind Contribution to the PIP-II project, with cavities supplied by LASA-INFN and power couplers and tuning systems supplied by Fermilab. This paper presents the CEA scope of work that includes the design, manufacturing, assembly and tests of the cryomodules and the upgrade of the existing infrastructures to the PIP-II requirements.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST011  
About • Received ※ 13 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 25 June 2022
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MOPOST015 Beam Dynamics Simulations for the Superconducting HELIAC CW Linac at GSI heavy-ion, linac, SRF, cryomodule 86
 
  • M. Schwarz, T. Conrad, H. Podlech
    IAP, Frankfurt am Main, Germany
  • K. Aulenbacher, F.D. Dziuba, S. Lauber, J. List
    IKP, Mainz, Germany
  • K. Aulenbacher, W.A. Barth, M. Basten, C. Burandt, F.D. Dziuba, V. Gettmann, T. Kürzeder, S. Lauber, J. List, M. Miski-Oglu, S. Yaramyshev
    HIM, Mainz, Germany
  • K. Aulenbacher, W.A. Barth, M. Basten, C. Burandt, F.D. Dziuba, V. Gettmann, M. Heilmann, T. Kürzeder, S. Lauber, J. List, M. Miski-Oglu, A. Rubin, S. Yaramyshev
    GSI, Darmstadt, Germany
  • W.A. Barth
    KPH, Mainz, Germany
  • H. Podlech
    HFHF, Frankfurt am Main, Germany
 
  Funding: Work supported by the German Federal Ministry of Education and Research (BMBF, contract no. 05P21RFRB2)
The superconducting (SC) continuous wave (CW) heavy ion linac HELIAC (HElm\-holtz LInear ACcelerator) is a common project of GSI and HIM under key support of IAP Frankfurt. It is intended for future experiments with heavy ions near the Coulomb barrier within super-heavy element (SHE) research and aims at developing a linac with multiple CH cavities as key components downstream the High Charge State Injector (HLI) at GSI. The design is challenging due to the requirement of intense beams in CW mode up to a mass-to-charge ratio of 6, while covering a broad output energy range from 3.5 to 7.3 MeV/u with minimum energy spread. In 2017 the first superconducting cavity of the linac has been successfully commissioned and extensively tested with beam at GSI. In the light of experience gained in this research so far, the beam dynamics layout for the entire linac has been updated and optimized in the meantime. This contribution will provide a brief overview of the recent progress on the project, as well as a potential modification to the linac layout.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST015  
About • Received ※ 08 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 03 July 2022 — Issue date ※ 10 July 2022
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MOPOST016 Proton Linac Design for the High Brilliance Neutron Source HBS rfq, linac, neutron, proton 90
 
  • M. Schwarz, M. Droba, K. Kümpel, S. Lamprecht, O. Meusel, N.F. Petry, H. Podlech
    IAP, Frankfurt am Main, Germany
  • J. Baggemann, Th. Brückel, T. Gutberlet, E. Mauerhofer, U. Rücker, A. Schwab, P. Zakalek
    JCNS, Jülich, Germany
  • J. Li
    IEK, Jülich, Germany
  • C. Zhang
    GSI, Darmstadt, Germany
 
  Due to the decommissioning of several reactors, only about half of the neutrons will be available for research in Europe in the next decade despite the commissioning of the ESS. High-Current Accelerator-driven Neutron Sources (HiCANS) could fill this gap. The High Brilliance Neutron Source (HBS) currently under development at Forschungszentrum Jülich is scalable in terms of beam energy and power due to its modular design. The driver linac will accelerate a 100 mA proton beam to 70 MeV. The linac is operated with a beam duty cycle of up to 13.6 % (15.3 % RF duty cycle) and can simultaneously deliver three pulse lengths (208 µs, 833 µs and 2 ms) for three neutron target stations. In order to minimize the development effort and the technological risk, state-of-the-art technology of the MYRRHA injector is used. The HBS linac consists of a front end (ECR source, LEBT, 2.5 MeV double RFQ) and a CH-DTL section with 44 room temperature CH-cavities. All RF structures are operated at 176.1 MHz and are designed for high duty cycle. Solid-state amplifiers up to 500 kW are used as RF drivers. Due to the beam current and the high average beam power of up to 952 kW, particular attention is paid to beam dynamics. In order to minimize beam losses, a quasi-periodic lattice with constant negative phase is used. This paper describes the conceptual design and the challenges of a modern high-power and high-current proton accelerator with high reliability and availability.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST016  
About • Received ※ 08 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 11 July 2022
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MOPOST025 Influences of the Transverse Motions of the Particles to the Recombination Rate of a Co-Propagating Electron-Ion System electron, experiment, alignment, target 112
 
  • G. Wang, D. Kayran, V. Litvinenko, I. Pinayev, P. Thieberger
    BNL, Upton, New York, USA
  • V. Litvinenko
    Stony Brook University, Stony Brook, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
For a system with the ion beam co-propagating with the electron beam, such as a traditional electron cooler or a Coherent electron Cooler (CeC), the recombination rate is an important observable for matching the energy of the electrons with the ions. In this work, we have developed the analytical expressions to investigate how the recombination rate depends on the energy difference of the two beams, with the influences from the transverse motions of the particles being considered. The analytical results are then used to analyze the measured recombination data collected during the CeC experiment in run 21 and run 22.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST025  
About • Received ※ 09 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 27 June 2022
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MOPOST029 Fast Cycling FFA Permanent Magnet Synchrotron proton, synchrotron, permanent-magnet, acceleration 126
 
  • D. Trbojevic, J.S. Berg, M. Blaskiewicz, S.J. Brooks
    BNL, Upton, New York, USA
 
  Funding: Work performed under the Contract Number DE-AC02-98CH10886 with the auspices of US Department of Energy
We present a novel concept of the Fixed-Field-Alternating (FFA) small racetrack proton accelerator 10x6 size, with kinetic energy range between 30-250 MeV made of permanent magnets. The horizontal and vertical tunes are fixed within the energy range, as the magnets The combined function magnets have additional sextupole and octupole multipoles the chromatic corrections, providing very fast cycling with a frequency of 1.3 KHz. The injector is 30 MeV commercially available cyclotron with RF frequency of 65 MHz. The permanent magnet synchrotron RF frequency is 390 MHz and acceleration uses the phase jump scheme.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST029  
About • Received ※ 08 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 04 July 2022
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MOPOST032 A New Approach to Cyclotron Design cyclotron, proton, extraction, ion-source 133
 
  • O. Karamyshev
    JINR, Dubna, Moscow Region, Russia
 
  Cyclotrons are the oldest type of circular accelerators, with many applications, design of the majority of cyclotrons nowadays follow has become a standard for most of developers, and there is a clear trend for switching towards superconducting magnets to increase the magnet field level and descrease the size and weight. A new approach, described in this paper allowed the author to design a lineup of cyclotrons from 15 to 230 MeV as compact and power efficient as superconducting cyclotrons, but using copper coil.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST032  
About • Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 04 July 2022
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MOPOST038 Excitation of the σll = 90° Resonance by the Cavity RF Accelerating Fields resonance, focusing, space-charge, linac 152
 
  • J.-M. Lagniel
    GANIL, Caen, France
 
  In RF linacs the longitudinal focusing is done by nonlinear forces and at high accelerating fields the zero-current longitudinal phase advance per longitudinal focusing period σ0ll can be high. The nonlinear components of the RF field (sextupolar, octupolar and higher order components) can then excite parametric resonances, including the 4th-order resonance (σll = 90°) when σ0ll is higher than 90°, inducing strong longitudinal emittance growths and acceptance reductions. The longitudinal beam dynamics is therefore complex, even when the nonlinear space-charge forces are ignored. The parametric resonance excitation by the RF field is analyzed before discussing the additional effect of the nonlinear space-charge forces, in particular to explain why the zero-current longitudinal phase advance per transverse focusing period σ0lt is not a relevant parameter. Examples are given in the SPIRAL2 linac case.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST038  
About • Received ※ 16 May 2022 — Accepted ※ 17 June 2022 — Issue date ※ 22 June 2022  
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MOPOST046 Enforcing the Convergence of Longitudinal Bunch Density Calculation in the Presence of a Harmonic Cavity Through Anderson Acceleration Method acceleration, synchrotron, storage-ring, superconductivity 180
 
  • I. Carvalho de Almeida
    CNPEM, Campinas, SP, Brazil
  • M. Hoffmann Wallner, A.P.B. Lima
    LNLS, Campinas, Brazil
 
  Sirius is a 4th generation synchrotron light source at the Brazilian Center for Research in Energy and Materials in Campinas, Brazil. A passive superconducting third harmonic cavity is planned to be installed in the storage ring in order to lengthen the bunches and increase beam lifetime by reducing Touschek scattering while keeping its high brightness. This paper presents the results obtained in applying Anderson acceleration method to enforce the convergence of the self-consistent algorithm used for calculation of the equilibrium longitudinal bunch density in the presence of a harmonic cavity.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST046  
About • Received ※ 08 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 18 June 2022  
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MOPOPT009 New Bunch-by-Bunch Filling Pattern Measuring System at ELSA FPGA, electron, synchrotron, controls 244
 
  • A.K. Wald, K. Desch, D. Elsner, D. Proft
    ELSA, Bonn, Germany
 
  The electron accelerator facility ELSA at the University of Bonn, Germany, can accelerate and store electrons with a final energy from 0.8GeV up to 3.2GeV. To routinely determine the filling pattern in the storage ring, a new measuring system has been developed. For hadron physics experiments the filling pattern, which is influenced by the injection from the pre-accelerating synchrotron, should be as homogeneous as possible. The new measurement system should provide a real-time measurement of the filling pattern, so that the injection can be continuously optimized. Moreover, a position measurement for each individual bunch is provided, from which the two transverse and the longitudinal tunes can be deduced. To measure the bunch-by-bunch intensity and position, the signals of the existing button-type BPMs will be digitized by fast 12-bit ADCs synchronized to the 500MHz ELSA radio frequency. The fast pre-processing and intermediate storage of the data is realized with a 500MHz clocked FPGA and transfers the data to a PC for further processing. First results of measurement system developed in-house will be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOPT009  
About • Received ※ 08 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 28 June 2022  
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MOPOPT012 Concept of a Beam Diagnostics System for the Multi-Turn ERL Operation at the S-DALINAC linac, operation, electron, recirculation 254
 
  • M. Dutine, M. Arnold, R. Grewe, L.E. Jürgensen, N. Pietralla, F. Schließmann, M. Steinhorst
    TU Darmstadt, Darmstadt, Germany
 
  Funding: Work supported by DFG (GRK 2128), BMBF (05H21RDRB1), the State of Hesse within the Research Cluster ELEMENTS (Project ID 500/10.006) and the LOEWE Research Group Nuclear Photonics.
The S-DALINAC is a thrice-recirculating electron accelerator operating in cw-mode at a frequency of 3 GHz. Due to the implementation of a path-length adjustment system capable of a 360° phase shift, it is possible to operate the accelerator as an Energy-Recovery LINAC. The multi-turn ERL operation has been demonstrated in 2021. While operating the accelerator in this mode, there are two sets of bunches, the still-to-be accelerated and the already decelerated beam, with largely different absolute longitudinal coordinates in the same beamline acting effectively as a 6 GHz beam. For this mode, a non-destructive, sensitive beam diagnostics system is necessary in order to measure the position of both beams simultaneously. The status of a 6 GHz resonant cavity beam position monitor (BPM) will be given together with the results of a wire scanner measurement of the multi-turn ERL beam.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOPT012  
About • Received ※ 02 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 28 June 2022
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MOPOPT028 Beam Diagnostics and Instrumentation for MESA experiment, operation, diagnostics, instrumentation 307
 
  • M. Dehn, K. Aulenbacher, J. Diefenbach, F. Fichtner, P. Heil, R.G. Heine, R.F.K. Kempf, C. Matejcek
    IKP, Mainz, Germany
  • C.L. Lorey
    KPH, Mainz, Germany
 
  Funding: Work supported by PRISMA and the German federal state of Rheinland-Pfalz
For the new Mainz Energy recovering Superconducting Accelerator (MESA) a wide range of beam currents is going to be used during machine optimization and for the physics experiments. To be able to monitor beam parameters like beam current, phases and beam positions several different kinds of beam instrumentation is foreseen. Some components have already been tested at the Mainz Microtron (MAMI) and others have been used at the MELBA test accelerator. In this paper we will present the current status of the instrumentation.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOPT028  
About • Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 02 July 2022
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MOPOPT058 Machine Learning Training for HOM Reduction in a TESLA-Type Cryomodule at FAST HOM, electron, emittance, experiment 400
 
  • J.A. Diaz Cruz
    UNM-ECE, Albuquerque, USA
  • J.A. Diaz Cruz, A.L. Edelen, B.T. Jacobson, J.P. Sikora
    SLAC, Menlo Park, California, USA
  • D.R. Edstrom, A.H. Lumpkin, R.M. Thurman-Keup
    Fermilab, Batavia, Illinois, USA
 
  Low emittance electron beams are of high importance at facilities like the Linac Coherent Light Source II (LCLS-II) at SLAC. Emittance dilution effects due to off-axis beam transport for a TESLA-type cryomodule (CM) have been shown at the Fermilab Accelerator Science and Technology (FAST) facility. The results showed the correlation between the electron beam-induced cavity high-order modes (HOMs) and the Beam Position Monitor (BPM) measurements downstream the CM. Mitigation of emittance dilution can be achieved by reducing the HOM signals. Here, we present a couple of Neural Networks (NN) for bunch-by-bunch mean prediction and standard deviation prediction for BPMs located downstream the CM.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOPT058  
About • Received ※ 15 June 2022 — Revised ※ 18 June 2022 — Accepted ※ 24 June 2022 — Issue date ※ 26 June 2022
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MOPOTK012 Concept of a Polarized Positron Source for CEBAF positron, electron, target, experiment 457
 
  • S.H. Habet, R.M. Bodenstein, S.A. Bogacz, J.M. Grames, A.S. Hofler, R. Kazimi, F. Lin, M. Poelker, Y. Roblin, A. Seryi, R. Suleiman, A.V. Sy, D.L. Turner
    JLab, Newport News, Virginia, USA
  • A. Ushakov
    Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
  • C.A. Valerio-Lizárraga
    ECFM-UAS, Culiacan, Sinaloa, Mexico
  • E.J-M. Voutier
    LPSC, Grenoble Cedex, France
 
  Funding: Laboratoire de Physique des 2 Infinis Irène Joliot-Curie Université Paris-Saclay -> Eric Voutier : eric.voutier@ijclab.in2p3.fr.
Positron beams would provide new and meaningful probes for the experimental program at the Thomas Jefferson National Accelerator Facility (JLab), including but not limited to future hadronic physics and dark matter experiments. Critical requirements involve generating positron beams with a high degree of spin polarization, sufficient intensity and a continuous-wave (CW) bunch train compatible with acceleration to 12 GeV at the Continuous Electron Beam Accelerator Facility (CEBAF). To address these requirements, a polarized positron injector based upon the bremsstrahlung of an intense CW spin polarized electron beam is considered*. First a polarized electron beam line provides >1 mA of polarized electrons at ~120 MeV to a high-power target for positron production. Next, a second beam line collects, shapes and aligns the spin of positrons for users. Finally, the positron beam is matched into the CEBAF acceptance for acceleration and transport to the end stations with energies up to 12 GeV. An optimized layout to provide positrons beams with intensity >100 nA (polarized) or intensity >3 µA (unpolarized) will be discussed in this poster.
* D. Abbott et al., "Production of Highly Polarized Positrons Using Polarized Electrons at MeV Energies", Phys. Rev. Lett., 116, 214801 (2016)
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK012  
About • Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 06 July 2022
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MOPOTK022 A Design Study of Injector System for Synchrotron Light Source linac, electron, gun, simulation 485
 
  • C. Kim, E.-S. Kim, C.S. Park
    KUS, Sejong, Republic of Korea
 
  This work presents a design study of a 200 MeV electron linear accelerator consisting of an electron gun, bunchers, and accelerator structures. We aimed to design the linac with low emittance and low energy spread. A coasting beam from a thermionic electron gun is bunched using a series of buncher cavities: sub-harmonic buncher (SHB), a pre-buncher (PB), and a Buncher. The bunched beam is then accelerated up to 200 MeV with 4 cascaded accelerating structures. The SHB was designed with one-cell standing wave structure for improving the bunching efficiency. The two types of the 500 MHz SHB were considered: elliptical and coupled-cavity linac types. We also investigated constant-gradient and constant-impedance types of 3 GHz multi-cell traveling wave resonators for following buncher cavities and accelerating structures. Depending on the type, geometries of each traveling wave structure (TWS) cavity were determined, and then the electromagnetic fields were calculated. RF powers and phases of each cavity along this linac system were optimized using beam dynamics simulation. Furthermore, the beam distributions in the transverse direction are adjusted using solenoid magnets in the lowenergy section as well as quad triplets in the high-energy section.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK022  
About • Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 10 June 2022 — Issue date ※ 17 June 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
MOPOTK023 Beam Dynamics Studies on the 50 MeV Electron Linear Accelerator for Ultra-High Dose Rates electron, gun, acceleration, cathode 489
 
  • Y. Lee, C. Kim, E.-S. Kim, C.S. Park
    KUS, Sejong, Republic of Korea
  • H.-S. Lee, H.S. Shin
    VITZRONEXTECH, Ansan-si, Gyeonggi-do, Republic of Korea
 
  Electron beams with ultra-high dose rates (>40 Gy/s), which enable effective radiotherapy to act on deep-seated tumors in less than a second, can be generated by linear accelerators. To successfully achieve FLASH radiotherapy, we have performed the 50 MeV linear accelerator design studies. The designed electron accelerator consists of a thermionic electron gun, sub-harmonic buncher, buncher and 2.856 GHz traveling wave structure. In this report the design layout and particle tracking simulation results of the 50 MeV electron linac with high beam current are presented in detail.
FLASH radiotherapy
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK023  
About • Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 15 June 2022
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MOPOTK043 Wakefield Effects Evaluation on Nanometer Small Beam at KEK-ATF wakefield, simulation, vacuum, alignment 556
 
  • Y. Abe, K. Kubo, T. Okugi, N. Terunuma
    Sokendai, Ibaraki, Japan
  • K. Kubo, T. Okugi, N. Terunuma
    KEK, Ibaraki, Japan
 
  Funding: This work was supported by JST, the establishment of university fellowships towards the creation of science technology innovation, Grant Number JPMJFS2136. This work was also supported by JST SPRING, Grant Number SDP221102.
Accelerator Test Facility (ATF) is R&D facility to evaluate final focus technology for small beam required by ILC. The final focus beamline(ATF2) sets the goal to achieve 37 nm vertical beam size and 41 nm beam size had been demonstrated. Moreover, a significant intensity dependence on a nanometer beam size was observed and several studies of the wakefield had been conducted [*,**,***]. ATF2 is a proper beamline for wakefield studies with low emittance beam and nanometer resolution cavity BPMs and a nanometer beam size monitor. The simulation results were qualitatively cross-checked with experimental results and showed that the effects of some vacuum components and BPMs were significant. Further analysis of the wakefield will be done for flexible components (e.g. bellows). An upgrade of the ATF2 beamline is proposed by including minimization of the wakefield sources, to establish technologies for stable nanometer beam.
*J.Snuverink et al., PHYS. REV.ACCEL. BEAMS19, 091002.
**T.Okugi et al., PASJ16, FRPI023, 2019.
***P.Korysko et al., PHYS. REV.ACCEL. BEAMS23, 121004.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK043  
About • Received ※ 20 May 2022 — Revised ※ 16 June 2022 — Accepted ※ 01 July 2022 — Issue date ※ 05 July 2022
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MOPOTK047 Cooling Performance in a Dual Energy Storage Ring Cooler electron, proton, storage-ring, damping 568
 
  • B. Dhital, G.A. Krafft
    ODU, Norfolk, Virginia, USA
  • Y.S. Derbenev, D. Douglas, G.A. Krafft, H. Zhang, Y. Zhang
    JLab, Newport News, Virginia, USA
  • F. Lin, V.S. Morozov
    ORNL RAD, Oak Ridge, Tennessee, USA
 
  Funding: EIC fellowship at Jefferson Lab
The longitudinal and transverse emittance growth in hadron beams due to intra-beam scattering (IBS) and other heating sources deteriorate the luminosity in a collider. Hence, a strong hadron beam cooling is required to reduce and preserve the emittance. The cooling of high energy hadron beam is challenging. We propose a dual energy storage ring-based electron cooler that uses an electron beam to extract heat away from hadron beam in the cooler ring while the electron beam is cooled by synchrotron radiation damping in the high energy damping ring. In this paper, we present a design of a dual energy storage ring-based electron cooler. Finally, the cooling performance is simulated using Jefferson Lab Simulation Package for Electron Cooling (JSPEC) for proton beams at the top energy of 275 GeV for Electron-Ion Collider.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK047  
About • Received ※ 06 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 26 June 2022
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MOPOTK051 Modeling a Nb3Sn Cryounit in GPT at UITF SRF, simulation, gun, electron 576
 
  • S. Pokharel, G.A. Krafft
    ODU, Norfolk, Virginia, USA
  • A.S. Hofler, G.A. Krafft
    JLab, Newport News, Virginia, USA
 
  Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177.
Nb3Sn is a prospective material for future superconducting RF (SRF) accelerator cavities. The material can achieve higher quality factors, higher temperature operation and potentially higher accelerating gradients (Eacc 96 MV/m) compared to conventional niobium. In this work, we performed modeling of the Upgraded Injector Test Facility (UITF) at Jefferson Lab utilizing newly constructed Nb3Sn cavities. We studied the effects of the buncher cavity and varied the gun voltages from 200-500 keV. We have calibrated and optimized the SRF cavity gradients and phases for the Nb3Sn five-cell cavities energy gains with the framework of General Particle Tracer (GPT). Our calculations show the beam goes cleanly through the unit. There is full energy gain out of the second SRF cavity but not from the first SRF cavity due to non-relativistic phase shifts.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK051  
About • Received ※ 20 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 19 June 2022
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MOPOTK053 RLAs with FFA Arcs for Protons and Electrons linac, SRF, hadron, optics 584
 
  • V.S. Morozov
    ORNL RAD, Oak Ridge, Tennessee, USA
  • J.F. Benesch, R.M. Bodenstein, S.A. Bogacz, A. Coxe, K.E. Deitrick, D. Douglas, B.R. Gamage, G.A. Krafft, K.E.Price. Price, Y. Roblin, A. Seryi
    JLab, Newport News, Virginia, USA
  • J.S. Berg, S.J. Brooks, F. Méot, D. Trbojevic
    BNL, Upton, New York, USA
  • D. Douglas
    Douglas Consulting, York, Virginia, USA
  • G.H. Hoffstaetter
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
 
  Funding: Authored in part by UT-Battelle, LLC, Jefferson Science Associates, LLC, and Brookhaven Science Associates, LLC under Contracts DE-AC05-00OR22725, DE-AC05-06OR23177, and DE-SC0012704 with the US DOE.
Recirculating Linear Accelerators (RLAs) provide an efficient way of producing high-power, high-quality, continuous-wave hadron and lepton beams. However, their attractiveness had been limited by the cumbersomeness of multiple recirculating arcs and by the complexity of the spreader and recombiner regions. The latter problem sets one of the practical limitations on the maximum number of recirculations. We present an RLA design concept where the problem of multiple arcs is solved using the Fixed-Field Alternating gradient (FFA) design as in CBETA. The spreader/recombiner design is greatly simplified using an adiabatic matching approach. It allows for the spreader/recombiner function to be accomplished by a single beam line. The concept is applied to the designs of a high-power hadron accelerator being considered at ORNL and a CEBAF electron energy doubling project, FFA@CEBAF, being developed at Jefferson lab.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK053  
About • Received ※ 10 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 21 June 2022
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MOPOTK062 Numerical Calibration of the Bead-Pull Setup for Beam Coupling Impedance Evaluation impedance, simulation, coupling, experiment 607
 
  • D.M.F. El Dali, E. Métral, C. Zannini
    CERN, Meyrin, Switzerland
  • G. De Michele, S. Fanella
    AVO-ADAM, Meyrin, Switzerland
 
  The bead-pull method is a commonly used electromagnetic field measurement technique exploited to tune a radiofrequency cavity to achieve design specifications. The frequency of a resonant cavity is perturbed by inserting a metallic or dielectric bead. For a given electromagnetic field, the amplitude of the perturbation depends only on the geometry of the perturbing object. Therefore, the calibration of the bead can be done in different resonant structures without loss of generality. In this paper, a method to perform an accurate calibration of the bead with electromagnetic simulations is proposed. Compared to the common practice of measuring a reference cavity, the flexibility given by the simulation method to study different bead shapes and sizes could be advantageous to optimize the measurement setup. A calibrated bead-pull setup allows to quantify the electric field and, therefore, the shunt impedance of the resonant modes of the cavity. As experimental benchmark, the beam coupling impedance measured with the calibrated bead-pull setup is compared with electromagnetic simulations.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK062  
About • Received ※ 07 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 20 June 2022 — Issue date ※ 20 June 2022
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MOPOTK065 Minimising Transverse Multipoles in Accelerating RF Cavities via Azimuthally Modulated Designs multipole, simulation, GUI, coupling 610
 
  • L.M. Wroe
    JAI, Oxford, United Kingdom
  • R. Apsimon
    Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
  • M. Dosanjh
    CERN, Meyrin, Switzerland
  • S.L. Sheehy
    The University of Melbourne, Melbourne, Victoria, Australia
 
  In this paper, we build upon previous work of designing RF structures that support modes with tailored multipolar fields by applying the concept to negate the transverse multipoles in accelerating RF cavities caused by the incorporation of waveguide slots and tuning deformations. We outline a systematic method for designing structures that minimise these transverse multipoles and present analysis of simulations of two different minimisation designs.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK065  
About • Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 06 July 2022
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MOPOTK066 Damping-Ring-Free Injector Design for Linear Colliders emittance, electron, SRF, laser 614
 
  • T. Xu, P. Piot
    Northern Illinois University, DeKalb, Illinois, USA
  • S.Y. Kim, P. Piot, J.G. Power
    ANL, Lemont, Illinois, USA
  • M. Kuriki
    HU/AdSM, Higashi-Hiroshima, Japan
 
  Funding: This work was supported by the US DOE contracts # DE-SC0018656 and # DE-SC0018234 (U.S.-Japan Science & Technology Cooperation Program in HEP) with NIU and No.DE-AC02-06CH11357 with ANL.
The current designs of future electron-positron linear colliders incorporate large and complex damping rings to produce asymmetric beams for beamstrahlung mitigation at the interaction point. This paper presents the design of an damping-ring-free electron injector capable of delivering flat electron beams with phase-space partition comparable to the electron-beam parameters produced downstream of the damping ring in the proposed international linear collider (ILC) design. The performance of the proposed configuration, its sensitivity to jitter along with its impact on spin-polarization is discussed.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK066  
About • Received ※ 07 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 13 June 2022
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MOPOMS022 Studies of a Ka-Band High Power Klystron Amplifier at INFN-LNF klystron, electron, gun, focusing 683
 
  • M. Behtouei, L. Faillace, A. Mostacci, B. Spataro
    LNF-INFN, Frascati, Italy
  • F. Bosco, M. Carillo, M. Migliorati, A. Mostacci, L. Palumbo
    Sapienza University of Rome, Rome, Italy
  • F. Di Paolo, S. Fantauzzi, A. Leggieri, F. Marrese, L. Valletti
    Università degli Studi di Roma "Tor Vergata", Roma, Italy
  • G. Torrisi
    INFN/LNS, Catania, Italy
 
  In the framework of the Compact Light XLS project, a Ka-band linearizer with electric field ranging from 100 to 150 MV/m is requested. In order to feed this structure, a proper Ka-band high power klystron amplifier with a high efficiency is needed. This paper reports a possible solution for a klystron amplifier operating on the TM010 mode at 36 GHz, the third harmonic of the 12 GHz linac frequency, with an efficiency of 44% and 10.6 MW radiofrequency output power. We discuss also here the high-power DC gun with the related magnetic focusing system, the RF beam dynamics and finally the multiphysics analysis of a high- power microwave window for a Ka-band klystron providing 16MW of peak power.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS022  
About • Received ※ 18 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 18 June 2022 — Issue date ※ 10 July 2022
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MOPOMS029 HPC Modeling of a High-Gradient C-Band Linac for Hard X-Ray Free-Electron Lasers simulation, electron, FEL, linac 703
 
  • T.B. Bolin, S. Biedron
    UNM-ECE, Albuquerque, USA
  • S. Sosa
    ODU, Norfolk, Virginia, USA
 
  The production of soft to hard x-rays (up to 25 keV) at XFEL (x-ray free-electron laser) facilities has enabled new developments in a broad range of disciplines. Great potential exists for new scientific discovery at higher energies (42+ keV) such as envisioned at MaRIE (Matter-Radiation Interactions in Extremes) at Los Alamos National Laboratory. These instruments can require a large amount of real estate, which quickly escalates costs: The driver of the FEL is typically an electron beam linear accelerator (LINAC) and the need for higher beam energies capable of generating these X-rays can dictate that the linac becomes longer. State of art accelerating technology is required to reduce the linac length by reducing the size of the cavities, providing for compact, high-frequency, high acceleration gradients. Here, we describe using the Argonne Leadership Computing Facility (ALCF) to facilitate our investigations into design concepts for future XFEL high-gradient LINAC’s in the C-band (~4-8 GHz). We investigate two different traveling wave (TW) geometries optimized for high-gradient operation as modeled at the ALCF using VSim software.*
* https://www.txcorp.com
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS029  
About • Received ※ 03 July 2022 — Accepted ※ 04 July 2022 — Issue date ※ 08 July 2022  
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TUOXSP2 Analysis of Low RRR SRF Cavities SRF, niobium, accelerating-gradient, radio-frequency 783
 
  • K. Howard, Y.K. Kim
    University of Chicago, Chicago, Illinois, USA
  • D. Bafia, A. Grassellino
    Fermilab, Batavia, Illinois, USA
 
  Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics. This work was supported by the University of Chicago.
Recent findings in the superconducting radio-frequency (SRF) community have shown that introducing certain impurities into high-purity niobium can improve quality factors and accelerating gradients. Success has been found in nitrogen-doping, diffusion of the native oxide into the niobium surface, and thin films of alternate superconductors atop a niobium bulk cavity. We question why some impurities improve RF performance while others hinder it. The purpose of this study is to characterize the impurity profile of niobium with a low residual resistance ratio (RRR) and correlate these impurities with the RF performance of low RRR cavities so that the mechanism of recent impurity-based improvements can be better understood and improved upon. Additionally, we perform a low temperature bake on the low RRR cavity to evaluate how the intentional addition of oxygen to the RF layer affects performance. We have found that low RRR cavities experience low temperature-dependent BCS resistance behavior more prominently than their high RRR counterparts. The results of this study have the potential to unlock a new understanding on SRF materials.
 
slides icon Slides TUOXSP2 [1.495 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUOXSP2  
About • Received ※ 08 June 2022 — Accepted ※ 11 June 2022 — Issue date ※ 25 June 2022  
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TUIZSP1 Status of the e+e Collider Projects in Asia and Europe: CEPC and FCC-ee collider, booster, positron, operation 815
 
  • X.C. Lou
    IHEP, Beijing, People’s Republic of China
  • M. Boscolo
    LNF-INFN, Frascati, Italy
  • F. Zimmermann
    CERN, Meyrin, Switzerland
 
  Since the Higgs boson discovery at CERN, precision measurement of its properties has become the first priority in the field of High Energy Physics. Two laboratories, CERN from Europe and IHEP from China, have proposed large scale circular electron-positron colliders, namely FCC-ee and CEPC. Record luminosities are expected in the center of mass energy range from 90 to about 365 GeV. In this talk the statuses of both projects are reviewed: Following the publication of the first CDR FCC-ee and CEPC entering the phase of consolidation and feasibility study. Special focus will be put on R&D plans, prototyping and key technologies.  
slides icon Slides TUIZSP1 [6.718 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUIZSP1  
About • Received ※ 07 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 25 June 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUIZSP2 The Muon Collider collider, target, emittance, solenoid 821
 
  • D. Schulte
    CERN, Meyrin, Switzerland
 
  Muon colliders are considered nowadays in the landscape of future lepton colliders. Since the MAP project in USA, an important effort is being made in Europe to identify the neccesary R&D to advance towards a Conceptual Design Report in the next years. The talk will review the status of the technologies and accelerator designs and will present the R&D plans.  
slides icon Slides TUIZSP2 [15.641 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUIZSP2  
About • Received ※ 07 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 21 June 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPOST005 RF Voltage Calibration Using Phase Space Tomography in the CERN SPS synchrotron, simulation, alignment, collective-effects 841
 
  • D. Quartullo, S.C.P. Albright, H. Damerau, A. Lasheen, G. Papotti, C. Zisou
    CERN, Meyrin, Switzerland
 
  Voltage calibration using longitudinal phase-space tomography is a purely beam-based technique to determine the effective RF voltage experienced by a bunch. It was applied in the SPS, separately to each of its six accelerating travelling wave structures. A low spread in voltage errors was obtained by carefully optimizing the number of acquired bunch profiles. The technique moreover provided the relative phases of the cavities, which allowed their alignment to be checked. Pairs of cavities were measured as well to validate the consistency of the single-cavity voltages. The beam measurements were repeated after several months to confirm the reproducibility of the results. Longitudinal beam dynamics simulations, including the full SPS impedance model, were performed as a benchmark. The aim was to verify that the effect of the cable transfer-function on the bunch profiles can be neglected, as well as collective effects and small errors in the accelerator parameters.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST005  
About • Received ※ 30 May 2022 — Revised ※ 13 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 25 June 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPOST006 Frequency-Dependent RF Voltage Calibration Using Longitudinal Tomography in the CERN PSB synchrotron, extraction, flattop, injection 845
 
  • D. Quartullo, S.C.P. Albright, H. Damerau
    CERN, Meyrin, Switzerland
 
  Longitudinal phase-space tomography reconstructs the phase-space distribution from a set of bunch profiles and the accelerator parameters, which includes the RF voltage. The quality of the reconstruction depends on the accuracy to which these parameters are known. Therefore, it can be used for beam-based RF voltage calibration by analysing oscillations of a mismatched bunch. The actual RF voltage may be different from the programmed one due to uncertainties of the electrical gap voltage measurements and intensity effects. Tomography-based RF voltage calibration was systematically performed with low-intensity bunches in all four rings of the PS Booster (PSB) at injection and extraction energy. For each of the three RF cavities present in a given ring, the calibration was performed separately to extract the voltage errors while avoiding any influence of phase misalignments. The number of synchrotron oscillation periods available for the voltage calibration was constrained by the short duration of the PSB flat-bottom and top. Longitudinal beam dynamics simulations using the full PSB impedance model were performed to benchmark the results provided by the calibrations.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST006  
About • Received ※ 30 May 2022 — Revised ※ 13 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 14 June 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPOST008 Digital Low-Level RF System for the CERN Linac3 Accelerator linac, controls, LLRF, operation 853
 
  • D. Valuch, R. Alemany-Fernández, Y. Brischetto, S.J. Faeroe, G. Piccinini, M.E. Soderen
    CERN, Meyrin, Switzerland
 
  A major consolidation of the aging RF system of the CERN Linac3, the ion source for the whole CERN accelerator chain, started during the Long Shutdown II. The main changes were an upgrade of the analogue Low-Level RF system (LLRF) and replacement of the 350 kW tube amplifiers by a solid-state equivalent. The state-of-the-art digital LLRF system enabled new sophisticated features in field manipulations, significantly increased the operational flexibility and improved operational reliability and availability. The paper presents the new architecture, a low noise master clock generator, digital signal processing with direct sampling of the RF signals, pulse parameter measurement or cavity resonance control.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST008  
About • Received ※ 27 May 2022 — Revised ※ 13 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 15 June 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPOST012 Sirius Storage Ring RF Plant Identification LLRF, controls, storage-ring, low-level-rf 865
 
  • D. Daminelli, F.K.G. Hoshino, A.P.B. Lima
    LNLS, Campinas, Brazil
  • M. Souza
    UNICAMP, Campinas, São Paulo, Brazil
 
  The design configuration of the Sirius Light Source RF System is based on two superconducting RF cavities and eight 65 kW solid-state amplifiers operating at 500 MHz. The current configuration, based on a 7-cell normal conducting PETRA cavity, was initially planned for commissioning and initial tests of the beamlines. A digital low-level RF (DLLRF) system based on ALBA topology has been operating since 2019. Sirius is currently operating in decay mode for beamline tests with 100 mA stored current. During the commissioning, several studies were carried out to increase the stored current with stable beam. This paper presents a study using parametric data-driven models to identify the Storage Ring RF plant, aiming to optimize the DLLRF PI control parameters.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST012  
About • Received ※ 08 June 2022 — Accepted ※ 23 June 2022 — Issue date ※ 01 July 2022  
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPOST013 Concept and Development of 65 kW Solid-State RF Amplifiers for Sirius operation, storage-ring, synchrotron, controls 868
 
  • M. Hoffmann Wallner, A.P.B. Lima
    LNLS, Campinas, Brazil
  • R.H.A. Farias
    CNPEM, Campinas, SP, Brazil
 
  Sirius is a 4th generation synchrotron light source currently operating with 100 mA stored beam and one room temperature RF cavity driven by two 65 kW solid-state amplifiers (SSAs). After installation of the cryogenic plant, two superconducting (SC) RF cavities are planned to replace the room temperature cavity. Each SC cavity is going to be driven by a 250 kW RF signal at 500 MHz, resulting from the combination of four 65 kW RF SSAs. Due to the recent development of 900 W solid-state power amplifier modules, a new topology is proposed for the four amplifiers that still need to be constructed. For the amplifier’s combining stage, a cavity combiner with 80 input ports was simulated. For the dividing stage, 8-way and 10-way power splitters were designed. The general scheme of the amplifier is presented, as well as simulation and measurement results.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST013  
About • Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 12 June 2022 — Issue date ※ 03 July 2022
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TUPOST014 Sirius Storage Ring RF System Status Update LLRF, operation, storage-ring, cryogenics 872
 
  • A.P.B. Lima, D. Daminelli, M. Hoffmann Wallner, F.K.G. Hoshino
    LNLS, Campinas, Brazil
  • I. Carvalho de Almeida, R.H.A. Farias
    CNPEM, Campinas, SP, Brazil
 
  Sirius’s nominal operation phase consists of two 500 MHz CESR-B type superconducting cavities, each being driven by four 65 kW solid-state amplifiers, and a passive superconducting third harmonic cavity. Currently a normal conducting 7-cell PETRA cavity is being used along with two 65 kW RF amplifiers and was recently able to achieve 100 mA stored current. The performance of the storage ring RF system and the updated installation plans update are presented and discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST014  
About • Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 23 June 2022
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TUPOST016 Status of LLRF and Resonance Control Dedicated Algorithms Extension for PolFEL controls, resonance, operation, FEL 880
 
  • W. Jalmuzna, W. Cichalewski, A. Napieralski, P.S. Sekalski
    TUL-DMCS, Łódź, Poland
 
  PolFEL (POLish Free Electron Laser) is the new super-conducting based facility, which is under construction in Poland. It will provide a continuous electron beam with energy up to 160 MeV, which will be converted to light pulses with wavelengths as short as 150 nm. CW (Continuous Wave) operation of the superconducting linear accelerator with narrow bandwidth and high electromagnetic field gradient (presumably above 30 MV/m for single structure) creates new challenges while dealing with RF field stability, the influence of mechanical de-tuning of resonating structures and must take into account all limits induced by power amplifiers and cryo-system. The real-time control algorithm responsible for RF field, motor tuners, and piezo control must strictly interact with each other to provide the satisfactory performance of the whole facility. In addition, constant monitoring of such parameters as detuning, bandwidth, power margins of the amplifier, state of cavities must be done. The paper presents the current status of implementation of PolFEL’s LLRF Controller (extending GDR to other modes of operation as SEL, PLL) and Piezo Controller (both hardware and firmware layers).  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST016  
About • Received ※ 08 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 03 July 2022
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TUPOST017 PEG Contribution to the LLRF System for Superconducting Elliptical Cavities of ESS Accelerator Linac LLRF, controls, hardware, electron 884
 
  • W. Cichalewski, G.W. Jabłoński, K. Klys, D.R. Makowski, A. Mielczarek, A. Napieralski, P. Perek, P. Plewinski
    TUL-DMCS, Łódź, Poland
  • A. Abramowicz, K. Czuba, M.G. Grzegrzółka, K. Oliwa, I. Rutkowski, W. Wierba
    Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
  • P.R. Bartoszek, K. Chmielewski, K. Kostrzewa, T. Kowalski, D. Rybka, M. Sitek, J. Szewiński, Z. Wojciechowski
    NCBJ, Świerk/Otwock, Poland
  • M. Jensen
    ESS, Lund, Sweden
  • A.J. Johansson, A.M. Svensson
    Lund University, Lund, Sweden
 
  The LLRF (Low-Level Radio Frequency) system optimizes energy transfer from the superconducting resonator to the accelerating beam. At ESS, one LLRF system regulates a single cavity. This digital system’s HW platform is the MTCA.4 standard. The system has been co-designed by ESS, Lund University, and the PEG (Polish Electronic Group) consortium. The PEG is also responsible for the system components design, evaluation, and production (like Local Oscillator Rear transition module, piezo tuner driver RTM, RTM carrier board, and others). The PEG delivers a HW/SW cavity simulator, an LLRF system test-stand, and provides necessary integration and installation services required for complete system preparation for the linac commissioning and operation phase. The paper summarizes the PEG work on the development and preparation of the LLRF systems for the ESS elliptical structures. The efforts concerning hardware and software components prototyping and evaluation are discussed. Moreover, we present the current status of the project, including components mass production, integration, and installation work.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST017  
About • Received ※ 08 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 19 June 2022 — Issue date ※ 20 June 2022
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TUPOST018 Long Pulse Operation of the E-XFEL Cryomodule operation, controls, LLRF, FEL 888
 
  • W. Cichalewski
    TUL-DMCS, Łódź, Poland
  • J.K. Sekutowicz
    DESY, Hamburg, Germany
 
  The CW operation becomes more attractive mode of beam and RF operation, even for infrastructures initially developed as pulsed experiments. Compared to the short (single ms) pulse the CW or long pulse (LP) operation allows for a more relaxed bunch scheme and enables higher bunch quantities during the experiment run. The Long Pulse operation scenario is one of the possible EXFEL modes of work in the future. LLRF systems that work in CW (and LP) are in operation worldwide. Most of them are dedicated to single cavity control. The XFEL dedicated system is capable of multicavity cryomodules vector-sum operation. In such a configuration switching from short-pulse operation into long-pulse with the existing limitations from the allowed cryo heat load level, average input power per coupler (and others) can be extremely challenging. For this setup the support from the dynamic resonance control system is essential. This paper summarizes efforts towards the successful vector-sum operation of the X-FEL type cryomodule in the LP operation mode. Modifications to the original LLRF setup together with challenges of narrow bandwidth operation in moderate and high gradients are discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST018  
About • Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 21 June 2022 — Issue date ※ 23 June 2022
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TUPOST021 The CERN SPS Low Level RF: The Beam-Control controls, LLRF, proton, hardware 895
 
  • A. Spierer, P. Baudrenghien, J. Egli, G. Hagmann, P. Kuzmanović, I. Stachon, M. Sumiński, T. Włostowski
    CERN, Meyrin, Switzerland
 
  The Super Proton Synchrotron (SPS) Low Level RF (LLRF) has been completely upgraded during the CERN long shutdown (LS2, 2019-2020). The old NIM and VME based, mainly analog system has been replaced with modern digital electronics implemented on a MicroTCA platform. The architecture has also been reviewed, with synchronization between RF stations now resting on the White Rabbit (WR) deterministic link. This paper is the first of a series of three on the SPS LLRF upgrade. It covers the Beam-Control part, that is responsible for the generation of the RF reference frequency from a measurement of the magnetic field, and beam phase and radial position. It broadcasts this frequency word to the RF stations, via a White Rabbit network. The paper presents the architecture, gives details on the signal processing, firmware, hardware and software. Finally, results from the first year of beam commissioning are presented (2021).  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST021  
About • Received ※ 07 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 05 July 2022  
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TUPOST022 The CERN SPS Low Level RF: Lead Ions Acceleration acceleration, injection, LLRF, controls 899
 
  • P. Baudrenghien, J. Egli, G. Hagmann, A. Spierer, T. Włostowski
    CERN, Meyrin, Switzerland
 
  This paper is the third of a series of three on the Super Proton Synchrotron (SPS) Low Level RF (LLRF). Its focus is the upgrade concerned with the acceleration of Lead ions for injection into the LHC. Lead ions are far from relativistic at injection into the SPS. Therefore, the classic acceleration scheme at constant harmonic number (h=4620) does not work as the RF frequency swing does not fit within the cavity bandwidth. Fixed Frequency Acceleration (FFA) is therefore used. The upgraded LLRF uses a completely new implementation of the FFA, based on a Numerically Controlled Oscillator (NCO) implemented as an FPGA IP in the Controller of each cavity. In addition, the 2022 scheme for LHC ions filling calls for slip stacking of two families of bunches, 100 ns spacing, to generate a 50 ns spacing after interleaving. The paper presents the key components for FFA and ions slip stacking as implemented in the new system, together with successful first tests performed in Autumn 2021.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST022  
About • Received ※ 08 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 24 June 2022  
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TUPOST023 The CERN SPS Low level RF: The Cavity-Controller controls, LLRF, feedback, proton 903
 
  • G. Hagmann, P. Baudrenghien, J. Egli, A. Spierer, M. Sumiński, T. Włostowski
    CERN, Meyrin, Switzerland
 
  This paper is the second of a series of three on the Super Proton Synchrotron (SPS) Low Level RF (LLRF) upgrade. It covers the 200MHz Cavity-Controller part, that is responsible for the regulation of the accelerating field in a single SPS cavity. When the SPS is used as Large Hadron Collider (LHC) proton injector, the issue is the high beam loading that must be compensated to guarantee longitudinal stability and constant parameters over the bunch train. That calls for strong One-Turn Delay Feedback (OTFB) and Feed-Forward (FFWD). The SPS is also accelerating Lead ions (Pb). There the issue is Frequency-Modulation (FM) and Amplitude-Modulation (AM) over the turn (so called Fixed Frequency Acceleration - FFA) plus RF gymnastics for the new ions slip-stacking. The paper reviews the functional requirements, presents the block diagram, then gives details on the signal processing, firmware and hardware. Finally results from the first year of beam commissioning are presented (2021).  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST023  
About • Received ※ 07 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 19 June 2022
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TUPOST024 A New Beam Loading Compensation and Blowup Control System Using Multi-Harmonic Digital Feedback Loops in the CERN Proton Synchrotron Booster controls, feedback, LLRF, operation 907
 
  • D. Barrientos, S.C.P. Albright, M.E. Angoletta, A. Findlay, M. Jaussi, J.C. Molendijk
    CERN, Meyrin, Switzerland
 
  As part of the LHC Injectors Upgrade, the CERN Proton Synchrotron Booster (PSB) has been upgraded with new wide-band Finemet cavities and a renovated Low-Level Radio Frequency system with digital cavity controllers implemented in FPGAs. Each controller synchronously receives the computed revolution frequency, used to generate 16 harmonic references. These are then used to IQ demodulate the voltage gap and modulate the 16 RF drive signals each controlled through a Cartesian feedback loop (with individual voltage and phase control). The sum of these digital drive signals is then sent to the cavities. In addition, a configurable blow-up system providing a sinusoidal or custom noise pattern can be used to excite the beam. An embedded network analyzer allows studying the stability of the feedback loops of the individual harmonics. The 16 harmonic feedback loops have been successfully operated during 2021, allowing to reduce the beam induced voltage and control the longitudinal emittance of the beam. In this paper we present the system architecture as well as the performance of the complete cavity controller during operation in the PSB.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST024  
About • Received ※ 23 May 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 28 June 2022
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TUPOST027 Machine Learning-Based Tuning of Control Parameters for LLRF System of Superconducting Cavities controls, LLRF, simulation, SRF 915
 
  • J.A. Diaz Cruz, S. Biedron
    UNM-ECE, Albuquerque, USA
  • J.A. Diaz Cruz
    SLAC, Menlo Park, California, USA
  • R. Pirayesh
    UNM-ME, Albuquerque, New Mexico, USA
  • S. Sosa
    ODU, Norfolk, Virginia, USA
 
  The multiple systems involved in the operation of particle accelerators use diverse control systems to reach the desired operating point for the machine. Each system needs to tune several control parameters to achieve the required performance. Traditional Low-Level RF (LLRF) systems are implemented as proportional-integral feedback loops, whose gains need to be optimized. In this paper, we explore Machine Learning (ML) as a tool to improve a traditional LLRF controller by tuning its gains using a Neural Network (NN). We present the data production scheme and a control parameter optimization using a NN. The NN training is performed using the THETA supercomputer.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST027  
About • Received ※ 14 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 20 June 2022
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TUPOST041 Experience with Computer-Aided Optimizations in LINAC4 and PSB at CERN linac, MMI, extraction, beam-losses 945
 
  • P.K. Skowroński, M.A. Fraser, I. Vojskovic
    CERN, Meyrin, Switzerland
 
  Accelerator optimization is routinely performed with the help of computer algorithms that fully automate these tasks. However, their efficiency, speed, and time to implement varies greatly depending on the algorithms used. In LINAC4 some of the automatic optimization routines were programmed using different algorithms to find the most suitable. We present the problems for which the computer algorithms were used and the results of our comparative study.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST041  
About • Received ※ 09 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 22 June 2022 — Issue date ※ 08 July 2022
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TUPOPT011 Start To End Simulation Study For Oscillator-Amplifier Free-Electron Laser electron, radiation, simulation, FEL 1022
 
  • H. Sun, Z.H. Zhu
    SINAP, Shanghai, People’s Republic of China
  • C. Feng, B. Liu
    SARI-CAS, Pudong, Shanghai, People’s Republic of China
  • Z.H. Zhu
    DESY, Hamburg, Germany
 
  External seeding techniques like high-gain harmonic generation (HGHG) and echo-enabled harmonic generation (EEHG) have been proposed and proven to be able to generate fully coherent radiation in the EUV and X-ray range. A big challenge is to combine the advantages of seeding schemes with high repetition rates. Recently, for seeding at a high repetition rate, an optical resonator scheme has been introduced to recirculate the radiation in the modulator to seed the high repetition rate electron bunches. Earlier studies have shown that a resonator-like modulator combined with an amplifier in high gain harmonic generation (HGHG) configuration can be used to generate radiation whose wavelength can reach the water window region. This scheme overcomes the limitation of requiring high repetition rate seed laser systems. In this contribution, we present start-to-end simulation results of a seeded oscillator-amplifier FEL scheme.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT011  
About • Received ※ 07 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 11 June 2022 — Issue date ※ 16 June 2022
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TUPOPT030 Design and Simulation of the MIR-FEL Generation System at Chiang Mai University FEL, electron, undulator, simulation 1074
 
  • S. Sukara, K. Kongmali, S. Rimjaem
    Chiang Mai University, Chiang Mai, Thailand
  • H. Ohgaki
    Kyoto University, Kyoto, Japan
 
  At the PBP-CMU Electron Linac Laboratory, the system to generate MIR-FEL using the electron linac has been developed. In this contribution, the design and simulation results of the MIR-FEL generation system are presented. The system is designed as the oscillator-FEL type consisting of two mirrors and a 1.6-m permanent planar undulator. The middle of the undulator is determined as the laser beam waist position. Both two mirrors are the concave gold-coated copper mirrors placing upstream and downstream the optical cavity, which has a total length of 5.41 m. The FEL is designed to coupling out at a hole with diameter of 2 mm on the upstream mirror. The optical cavity is optimized to obtain high FEL gain and high FEL power using GENESIS 1.3 simulation code. The electron beam with energy of 25 MeV is used in the consideration. As a result, the MIR-FEL with central wavelength of 13.01 ’m is obtained. The optimum upstream and downstream mirror curvatures are 3.091 m and 2.612 m, respectively, which give the Rayleigh length of 0.631 m. This optical cavity yields the power coupling ratio of 1:1000 and the FEL gain of up to 40%. The extracted MIR-FEL peak power in 100 kW scale is obtained at the coupling hole. The construction of the practical MIR-FEL system is conducted based on the results from this study.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT030  
About • Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 01 July 2022
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TUPOPT039 Characterization of Diamond with Buried Boron-Doped Layer Developed for Q-Switching an X-Ray Optical Cavity FEL, laser, lattice, ECR 1097
 
  • R.A. Margraf, A. Halavanau, Z. Huang, J. Krzywiński, J.P. MacArthur, G. Marcus, M.L. Ng, A.R. Robert, R. Robles, T. Sato, D. Zhu
    SLAC, Menlo Park, California, USA
  • Z. Huang, F. Ke, R. Robles, Y. Zhong
    Stanford University, Stanford, California, USA
  • S.-K. Mo, Y. Zhong
    LBNL, Berkeley, California, USA
  • P. Pradhan
    ANL, Lemont, Illinois, USA
  • A.R. Robert
    MAX IV Laboratory, Lund University, Lund, Sweden
  • M.D. Ynsa
    UAM, Madrid, Spain
 
  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.
X-ray Free-Electron Laser Oscillators (XFELOs) and X-ray Regenerative Amplifier FELs (XRAFELs) are currently in development to improve longitudinal coherence and spectral brightness of XFELs. These schemes lase an electron beam in an undulator within an optical cavity to produce X-rays. X-rays circulate in the cavity and interact with fresh electron bunches to seed the FEL process over multiple passes, producing progressively brighter and more spectrally pure X-rays. Typically, the optical cavities used are composed of Bragg-reflecting mirrors to provide high reflectivity and spectral filtering. This high reflectivity necessitates special techniques to out-couple X-rays from the cavity to deliver them to users. One method involves "Q-switching" the cavity by actively modifying the reflectivity of one Bragg-reflecting crystal. To control the crystal lattice constant and thus reflectivity, we use an infrared laser to heat a buried boron layer in a diamond crystal. Here, we build on earlier work in Krzywinski et al.* and present the current status of our Q-switching diamond, including implantation with 9 MeV boron ions, annealing, characterization and early tests.
*Krzywinski et al., "Q-switching of X-Ray Optical Cavities by using Boron Doped Buried Layer under a Surface of a Diamond Crystal," Proceedings of FEL2019, Hamburg, Germany, TUP033, 2019.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT039  
About • Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 08 July 2022
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TUPOPT047 Progress Report on Population Inversion X-Ray Laser Oscillator at LCLS laser, target, experiment, FEL 1107
 
  • A. Halavanau, R. Alonso-Mori, A. Aquila, U. Bergmann, F.-J. Decker, F. Fuller, M. Liang, A.A. Lutman, R.A. Margraf, R.H. Paul, C. Pellegrini
    SLAC, Menlo Park, California, USA
  • R. Ash, N.B. Welke
    UW-Madison/PD, Madison, Wisconsin, USA
  • A.I. Benediktovitch
    DESY, Hamburg, Germany
  • S.C. Krusic
    JSI, Ljubljana, Slovenia
  • N. Majernik, P. Manwani, J.B. Rosenzweig
    UCLA, Los Angeles, California, USA
  • R. Robles
    Stanford University, Stanford, California, USA
  • N. Rohringer
    Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
 
  We report the progress in the design and construction of a population inversion x-ray laser oscillator (XLO) using LCLS as an x-ray laser pump, being developed by a SLAC, CFEL, University of Hamburg (Germany), University of Wisconsin, Josef Stefan Institute (Slovenia) and UCLA collaboration. In this proceeding, we will present the latest XLO design and numerical simulations substantiated by our first experimental results. In our next experimental step XLO will be tested on the Coherent X-ray Imaging (CXI) end-station at LCLS as a two pass Regenerative Amplifier operating at the Copper Kα1 photon energy of 8048 eV. When built, XLO will generate fully coherent transform limited pulses with about 50 meV FWHM bandwidth. We expect the XLO will pave the way for new user experiments, e.g. in inelastic x-ray scattering, parametric down conversion, quantum science, x-ray interferometry, and external hard x-ray XFEL seeding.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT047  
About • Received ※ 12 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 24 June 2022
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TUPOPT048 bERLinPro Becomes SEALab: Status and Perspective of the Energy Recovery Linac at HZB linac, SRF, electron, experiment 1110
 
  • A. Neumann, B. Alberdi-Esuain, T. Birke, P. Echevarria, D. Eichel, F. Falkenstern, R. Fleischhauer, A. Frahm, F. Göbel, A. Heugel, F. Hoffmann, H. Huck, T. Kamps, S. Klauke, G. Klemz, J. Kolbe, J. Kühn, B.C. Kuske, J. Kuszynski, S. Mistry, N. Ohm, H. Ploetz, S. Rotterdam, O. Schappeit, G. Schindhelm, C. Schröder, M. Schuster, H. Stein, E. Suljoti, Y. Tamashevich, M. Tannert, J. Ullrich, A. Ushakov, J. Völker, C. Wang
    HZB, Berlin, Germany
  • T. Kamps
    HU Berlin, Berlin, Germany
 
  Funding: Work supported by German Bundesministerium für Bildung und Forschung, Land Berlin, and grants of Helmholtz Association
Since end of the year 2020 the energy recovery linac (ERL) project bERLinPro of Helmholtz-Zentrum Berlin has been officially completed. But what is the status of this facility, the next scientific goals in the framework of accelerator physics at HZB, what are the perspectives? To reflect the continuation of this endeavor and the broadening of applications of this machine from high current SRF based energy recovery concept up to an ultrafast electron diffraction (UED) facility producing shortest electron pulses, the facility is now named Sealab, Superconducting RF Electron Accelerator Laboratory. In this contribution, an overview of lessons learned so far, the status of the machine, the coming set up and commissioning steps with an outlook to midterm and future applications will be given. In summary, Sealab will expand, including the ERL application, and become a general accelerator physics and technology test machine to employ UED as a first study case and will also be an ideal testbed to investigate new control schemes based on digital twins or machine learning methods.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT048  
About • Received ※ 06 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 03 July 2022
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TUPOPT051 Reconstruction and Beam-Transport Study of the cERL Dump Line for High-Power IR-FEL Operation FEL, operation, beam-transport, electron 1117
 
  • N. Nakamura, K. Harada, N. Higashi, R. Kato, S. Nagahashi, K.N. Nigorikawa, T. Nogami, T. Obina, H. Sagehashi, H. Sakai, M. Shimada, R. Takai, O.A. Tanaka, Y. Tanimoto, T. Uchiyama, A. Ueda
    KEK, Ibaraki, Japan
 
  Funding: This work is supported by a NEDO project "Development of advanced laser processing with intelligence based on high-brightness and high-efficiency laser technologies."
A significant FEL pulse energy was successfully generated at the cERL IR-FEL in Burst mode where a macro pulse of about 1 microsecond or less is repeated at the maximum frequency of 5 Hz. In the next step, high-power FEL operation in CW mode should be carried out with energy recovery by increasing electron bunches drastically. However, momentum spread of the electron beam increases due to the FEL-light emission and the space charge effects and may cause serious beam loss by exceeding the momentum acceptance of the cERL downstream of the FEL. Therefore, we reconstructed the dump line in Autumn 2020 in order to greatly increase the momentum acceptance with improvement of the beam-tuning flexibility. Then we performed the beam-transport study of the reconstructed dump line in March 2021 by injecting the beam directly from the injector without passing the recirculation loop. In this paper, we present the reconstructed dump line and the beam-transport study.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT051  
About • Received ※ 16 May 2022 — Revised ※ 11 June 2022 — Accepted ※ 12 June 2022 — Issue date ※ 13 June 2022
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TUPOPT062 A Data-Driven Anomaly Detection on SRF Cavities at the European XFEL FEL, network, SRF, experiment 1152
 
  • A. Sulc, A. Eichler, T. Wilksen
    DESY, Hamburg, Germany
 
  Funding: This work was supported by HamburgX grant LFF-HHX-03 to the Center for Data and Computing in Natural Sciences (CDCS) from the Hamburg Ministry of Science, Research, Equalities and Districts.
The European XFEL is currently operating with hundreds of superconducting radio frequency cavities. To be able to minimize the downtimes, prevention of failures on the SRF cavities is crucial. In this paper, we propose an anomaly detection approach based on a neural network model to predict occurrences of breakdowns on the SRF cavities based on a model trained on historical data. We used our existing anomaly detection infrastructure to get a subset of the stored data labeled as faulty. We experimented with different training losses to maximally profit from the available data and trained a recurrent neural network that can predict a failure from a series of pulses. The proposed model is using a tailored architecture with recurrent neural units and takes into account the sequential nature of the problem which can generalize and predict a variety of failures that we have been experiencing in operation.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT062  
About • Received ※ 17 May 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 24 June 2022
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TUPOTK002 Results of the RF Power Tests of the ESS Cryomodules Tested at CEA cryomodule, electron, detector, cryogenics 1186
 
  • O. Piquet, S. Berry, A. Bouygues, E. Cenni, G. Devanz, C. Madec, C. Mayri, P. Sahuquet
    CEA-DRF-IRFU, France
  • C. Arcambal, Q. Bertrand, P. Bosland, T. Hamelin
    CEA-IRFU, Gif-sur-Yvette, France
  • M.J. Ellis
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • P. Pierini
    ESS, Lund, Sweden
  • D. Sertore
    INFN/LASA, Segrate (MI), Italy
 
  Eight of the medium and high beta cryomodules deliv-ered to ESS by CEA are tested at CEA before delivery; the two medium and high beta prototypes and the three first of each type of the series. The goal of these tests is to validate the assembly and the performances on few cryomodules before the next cryomodules of the series are delivered to ESS. This paper summarizes the general results obtained during the tests at 2 K and at high RF power, Pmax = 1.1 MW. The cavities reach the ESS re-quirements, Eacc = 16.7 MV/m (Medium beta) and 19.9 MV/m (High beta) with an efficient compensation of the Lorentz detuning by the piezo tuner over the full RF pulse length of 3.6 ms at 14 Hz. After the successful tests at CEA, the first cryomodules have been shipped to ESS where the final acceptance test are performed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK002  
About • Received ※ 03 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 21 June 2022
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TUPOTK003 High Power RF Conditioning of the ESS RFQ rfq, vacuum, operation, interlocks 1189
 
  • O. Piquet, A.C. Chauveau, P. Hamel
    CEA-IRFU, Gif-sur-Yvette, France
  • M. Baudrier, M.J. Desmons
    CEA-DRF-IRFU, France
  • B. Jones, D. Noll, A.G. Sosa, E. Trachanas, R. Zeng
    ESS, Lund, Sweden
 
  The 352.21 MHz Radio Frequency Quadrupole (RFQ) for the European Spallation Source ERIC (ESS) has been delivered by the end of 2019 by CEA/IRFU. The RFQ is designed to accelerate a 70 mA proton beam from 75 keV up to 3.62 MeV. It consists of a 4-vane resonant cavity with a total length of 4.6 m. Two coaxial power loop couplers feed the RFQ with the 1.4 MW of RF power required for beam operation. This paper first presents the main systems required for the RFQ conditioning. Then it summarizes the main steps and results of this high power RF conditioning completed at ESS from June 9 to July 29, 2021 in order to achieve the nominal field for a pulse length of 3.2ms at the repetition rate of 14Hz.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK003  
About • Received ※ 08 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 09 July 2022
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TUPOTK004 Time Resolved Field Emission Detection During ESS Cryomodule Tests cryomodule, radiation, electron, neutron 1192
 
  • E. Cenni, G. Devanz, O. Piquet
    CEA-IRFU, Gif-sur-Yvette, France
  • M. Baudrier, L. Maurice
    CEA-DRF-IRFU, France
 
  At CEA-Saclay we are currently testing the European Spallation Source (ESS) high beta cryomodules (CM). Each cryomodule is equipped with four superconducting elliptical cavities with their ancillaries (fundamental power couplers (FPC), frequency tuners and magnetic shields). The cavity are designed to accelerate protons with relativistic speed about β=0.86 and operate at an accelerating field of 19.9MV/m. During cryomodule test, operational parameters are inspected by powering up one cavity at the time. A dedicated gamma ray detection system has been designed and installed around the cryomodule in order to have a more precise insight into field emission phenomenon occurring during cryomodule operation. Recently we were able to obtain time resolved data concerning radiation emerging from the cavities due to field emission.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK004  
About • Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 02 July 2022
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TUPOTK005 Mitigation of Parasitic Losses in the Quadrupole Resonator Enabling Direct Measurements of Low Residual Resistances of SRF Samples niobium, quadrupole, SRF, simulation 1196
 
  • S. Keckert, R. Kleindienst, J. Knobloch, F. Kramer, O. Kugeler, D.B. Tikhonov
    HZB, Berlin, Germany
  • W. Ackermann, H. De Gersem
    TEMF, TU Darmstadt, Darmstadt, Germany
  • X. Jiang, A.O. Sezgin, M. Vogel
    University Siegen, Siegen, Germany
  • J. Knobloch
    University of Siegen, Siegen, Germany
  • M. Wenskat
    University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
 
  The quadrupole resonator (QPR) is a dedicated sample-test cavity for the RF characterization of superconducting samples in a wide temperature, RF field and frequency range. Its main purpose are high resolution measurements of the surface resistance with direct access to the residual resistance thanks to the low frequency of the first operating quadrupole mode. Besides the well-known high resolution of the QPR, a bias of measurement data towards higher values has been observed, especially at higher harmonic quadrupole modes. Numerical studies show that this can be explained by parasitic RF losses on the adapter flange used to mount samples into the QPR. Coating several micrometer of niobium on those surfaces of the stainless steel flange that are exposed to the RF fields significantly reduced this bias, enabling a direct measurement of a residual resistance smaller than 5 nano-Ohm at 2 K and 413 MHz.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK005  
About • Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 28 June 2022
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TUPOTK006 Systematic Investigation of Flux Trapping Dynamics in Niobium Samples experiment, SRF, controls, niobium 1200
 
  • F. Kramer, S. Keckert, S. Keckert, J. Knobloch, J. Knobloch, O. Kugeler
    HZB, Berlin, Germany
  • J. Knobloch, O. Kugeler
    BESSY GmbH, Berlin, Germany
  • J. Knobloch
    University of Siegen, Siegen, Germany
 
  Trapped magnetic flux in superconducting cavities can significantly increase surface resistance, and, thereby, limits the cavities’ performance. To reduce trapped flux in cavities, a better understanding of the fundamental mechanism of flux trapping is vital. We develop a new experimental design: measuring magnetic flux density at 15 points just above a niobium sheet of dimensions (100 x 60 x 3) mm with a time resolution of up to 2 ms and a flux resolution better than 0.5 µT. This setup allows us to control the temperature gradient and cooldown rate, both independently of each other, as well as the magnitude and direction of an external magnetic field. We present data gathered on a large-grain sample as well as on a fine-grain sample. Our data suggests that not only the temperature gradient but also the cooldown rate affects trapped flux. Additionally, we detect a non-trivial relationship between trapped flux and magnitude of applied field.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK006  
About • Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 16 June 2022
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TUPOTK008 Cavity Designs for the Ch3 to Ch11 and Bellow Tuner Investigation of the Superconducting Heavy Ion Accelerator Heliac SRF, heavy-ion, simulation, niobium 1204
 
  • T. Conrad, M. Busch, H. Podlech, M. Schwarz
    IAP, Frankfurt am Main, Germany
  • K. Aulenbacher
    IKP, Mainz, Germany
  • K. Aulenbacher, W.A. Barth, F.D. Dziuba, V. Gettmann, T. Kürzeder, S. Lauber, J. List, M. Miski-Oglu
    HIM, Mainz, Germany
  • W.A. Barth, M. Basten, F.D. Dziuba, M. Heilmann, A. Rubin, A. Schnase, S. Yaramyshev
    GSI, Darmstadt, Germany
 
  New CH-DTL cavities designs of the planned Helmholtz Linear Accelerator (HELIAC) are developed in collaboration of HIM, GSI and IAP Frankfurt. The linac, operated in cw-mode with a final energy of 7.3 MeV/u, is intended for various experiments, in particular with heavy ions at energies close to the Coulomb barrier for research on SHE. Twelve sc CH cavities are foreseen, divided into four different cryostats. Each cavity will be equipped with dynamic bellow tuner. After successful beam tests with CH0, CH3 to CH11 are being designed. Based on the experience gained so far, optimization will be made, which will lead to both an increase in performance in terms of reducing the peak fields limiting superconductivity and a reduction in manufacturing costs and time. In order to optimize manufacturing, attention was paid to design many parts of the cavity, such as lids, spokes, tuner and helium shell, with the same geometrical dimensions. In addition, a tuner test rig was developed, which will be used to investigate the mechanical properties of the bellow tuner. For this purpose, different simulations were made in order to realize conditions as close as possible to reality in the test rig.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK008  
About • Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 17 June 2022
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TUPOTK009 Development of Superconducting CH Cavity Preparation at IAP simulation, coupling, ECR, vacuum 1208
 
  • P. Müller, H. Podlech
    IAP, Frankfurt am Main, Germany
  • K. Aulenbacher, F.D. Dziuba, V. Gettmann, T. Kürzeder, M. Miski-Oglu
    HIM, Mainz, Germany
  • W.A. Barth, M. Basten, V. Gettmann, T. Kürzeder, M. Miski-Oglu
    GSI, Darmstadt, Germany
 
  Funding: HIC for FAIR, BMBF Contr. No. 05P21RFRB2 and HFHF
Goethe University (GU), Gesellschaft für Schwerionenforschung (GSI) and Helmholtz Institut Mainz (HIM) work in collaboration on the Helmholtz Linear Accelerator (HELIAC). A new superconducting (sc) continous wave (cw) high intensity heavy ion linear accelerator (Linac) will provide ion beams with maximum duty factor up to beam energies of 7.3 MeV/u. The acceleration voltage will be provided by sc Crossbar-H-mode (CH) cavities, developed of Institute for Applied Physics (IAP) at GU. Cavity preparation is researched and optimized towards widely used elliptical multicell cavities. A standardized preparation protocol for CH cavities is researched in collaboration between GU, GSI and HIM on a 360 MHz 19 gap CH prototype. Baseline measurements and a 120°C 48 hour bake produced higher maximum gradient, higher intrinsic quality factor and a shorter cavity conditioning phase. As a critical preparation step, High Pressure Rinsing (HPR) with ultra pure water will be performed at HIM and is currently in preparation. HPR cycles are currently tested on a CH dummy with a new nozzle layout that is optimized towards CH cavity geometry.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK009  
About • Received ※ 08 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 18 June 2022 — Issue date ※ 02 July 2022
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TUPOTK010 Nitric Acid Soaking after Imperfect Furnace Treatments niobium, SRF, radio-frequency, linac 1211
 
  • R. Ghanbari, A. Dangwal Pandey
    DESY, Hamburg, Germany
  • C. Bate
    University of Hamburg, Hamburg, Germany
  • W. Hillert, M. Wenskat
    University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
 
  Annealings of niobium cavities in UHV or nitrogen atmospheres are crucial for the performance in the later cryogenic tests and operation. Recovery methods for imperfect annealing conditions have been discussed, and a more recent proposal, the so-called "nitric acid soak" has been studied here in detail. It shows surprising recovery potential, albeit the unclear origin of this improvement. We present our investigation on the several potential origins. For this, we used SEM, SIMS and XPS measurements of niobium samples to study the surface morphology and contaminations. We can reject the favored hypothesis on the origin of the improvement, and propose an alternative origin.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK010  
About • Received ※ 10 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 18 June 2022
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TUPOTK011 Commissioning of a New Magnetometric Mapping System for SRF Cavity Performance Tests SRF, niobium, ECR, superconducting-cavity 1215
 
  • J.C. Wolff, J. Eschke, A. Gössel, D. Reschke, L. Steder, L. Trelle
    DESY, Hamburg, Germany
  • W. Hillert
    University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
 
  Funding: This work was supported by the Helmholtz Association within the topic Accelerator Research and Development (ARD) of the Matter and Technologies (MT) Program.
Magnetic flux trapped in the niobium bulk material of superconducting radio frequency (SRF) cavities degrades their quality factor and the accelerating gradient. The sensitivity for flux trapping is mainly determined by the treatment and the geometry of the cavity as well as the niobium grain size and orientation. To potentially improve the flux expulsion characteristics of SRF cavities and hence the efficiency of future accelerator facilities, further studies of the trapping behavior are essential. For this purpose a magnetometric mapping system to monitor the magnetic flux along the outer cavity surface of 1.3 GHz TESLA-Type single-cell SRF cavities has been developed and is currently in the commissioning phase at DESY. Contrary to similar approaches, this system digitizes the sensor signals already inside of the cryostat to extensively reduce the number of required cable feedthroughs. Furthermore, the signal-to-noise ratio (SNR) and consequently the measuring sensitivity can be enhanced by shorter analog signal lines, less thermal noise and the Mu-metal shielding of the cryostat. In this contribution test results gained by a prototype of the mapping system are presented.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK011  
About • Received ※ 10 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 29 June 2022
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TUPOTK012 Nitrogen Infusion Sample R&D at DESY niobium, vacuum, ECR, accelerating-gradient 1219
 
  • C. Bate
    University of Hamburg, Hamburg, Germany
  • A. Ermakov, D. Reschke, J. Schaffran
    DESY, Hamburg, Germany
  • W. Hillert, M. Wenskat
    University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
 
  Funding: This work was supported by the Helmholtz Association within the topic Accelerator Research and Development (ARD) of the Matter and Technologies (MT) Program.
Many accelerator projects such as the ILC would benefit from cavities with reduced surface resistance (high Q-values) while maintaining a high accelerating gradient. A possible way to meet the requirements is the so-called nitrogen-infusion procedure on Niobium cavities. However, a fundamental understanding and a theoretical model of this method are still missing. One important parameter is the residual resistance ratio (RRR) which is related to the impurity content of the material. We report the investigated RRR on samples in a wide temperature range in a vacuum and under a nitrogen atmosphere. This comparison made it possible to make statements about the differences in the concentration of nitrogen by varying the temperature. The samples are pure cavity-grade niobium and treated in the same manner as cavities. For this purpose, a small furnace dedicated to sample treatment was set up to change and explore the parameter space of the infusion recipe. Care was taken to achieve the highest level of purity possible in the furnace and in a pressure range of 1.0·10-8 mbar in order to meet the high requirements of nitrogen infusion.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK012  
About • Received ※ 08 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 01 July 2022
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TUPOTK013 PEALD SIS Studies for SRF Cavities SRF, site, plasma, niobium 1222
 
  • I. González Díaz-Palacio, R.H. Blick, A. Stierle, R. Zierold
    University of Hamburg, Hamburg, Germany
  • W. Hillert, M. Wenskat
    University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
  • A. Jeromin
    DESY Nanolab, FS-NL, Hamburg, Germany
  • T.F. Keller, N. Krupka, M. Wenskat
    DESY, Hamburg, Germany
 
  Recent technological advances and material treatments have pushed Nb SRF cavities to their maximum RF performance. A novel approach for overcoming this limitation, which takes advantage of RF field only penetrates into the superconductor at a certain distance called London penetration depth, is nano-structuring multilayers with PEALD (plasma-enhanced atomic layer deposition). SIS (superconductor-insulator-superconductor) multilayers provide magnetic screening of the bulk Nb cavity, increasing the field at which the vortex penetration starts, and higher quality factor. ALD is closely related to chemical vapor deposition and bases on sequential self-limit gas-solid surface reactions facilitating conformal coatings with sub-nm precision even on complex substrates such as the interior of a cavity. As a preliminary study for SIS SRF cavities, we investigated the AlN-NbTiN/NbN multilayers grown by PEALD. Different compositions, thicknesses, and post-deposition thermal treatments have been investigated. The characterization results of superconducting properties, elemental composition, crystallinity, and cross-section are shown in this contribution.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK013  
About • Received ※ 09 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 27 June 2022
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TUPOTK014 Refurbishment of SRF Cavities and HOM Antenna Coating Studies for the Mainz Energy-Recovering Superconducting Accelerator (MESA) cryomodule, HOM, SRF, linac 1226
 
  • P.S. Plattner, F. Hug, T. Stengler
    KPH, Mainz, Germany
 
  Funding: The work received funding by BMBF through 05H21UMRB1.
The Mainz Energy-Recovering Superconducting Accelerator (MESA) will be a new recirculating accelerator, which can operate in an external beam mode and an energy recovering mode. In the ERL-mode the electrons cross an internal gas-target at MAGIX and give their kinetic energy into the Superconducting Radio Frequency (SRF) system back after experimental use. The MESA cryomodules are based on ELBE-type cryomodules, which contain two 9-cell TESLA/XFEL-type cavities. For any maintenance the clean room infrastructure at the Helmholtz Institute Mainz (HIM) can be used. Currently, a cryomodule from the decommissioned ALICE ERL at Daresbury, UK is in the process of refurbishment. The refurbishment includes an HPR rinse of the cavities suffering from field emission at present and various adjustments of the module for a future use in MESA, which includes adding piezo tuners and new HOM antennas. For the new antennas, different superconducting coatings (Nb3Sn and NbTiN) will be tested to reach higher critical temperatures in the future for giving the possibility to couple out more HOM power without quenching as the prospected cw beamload lays above 4 mA in MESA ERL operation. Using a superconducting 3 GHz six-cell injector cavity for the S-DALINAC the successful refurbishment of a SRF cavity by applying a high pressure rinse in the clean room infrastructure at HIM was demonstrated the first time.
* The authors acknowledge the transfer of one cryomodule to Mainz by STFC Daresbury.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK014  
About • Received ※ 07 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 18 June 2022 — Issue date ※ 23 June 2022
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TUPOTK015 HOM Coupler Design and Optimization for the FCC-ee W Working Point HOM, impedance, multipactoring, damping 1230
 
  • S. Udongwo, S.G. Zadeh, U. van Rienen
    Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
  • R. Calaga
    CERN, Meyrin, Switzerland
 
  Funding: Funded by CERN under ADDENDUM FCC-GOV-CC-00213 (KE4978/ ATS) to FCC-GOV-CC- 0213/2431149/KE4978 VERSION 1.0.
The Future Circular electron-positron Collider (FCC-ee) is planned to operate with beam energies from 45.6 to 182.5 GeV and beam currents from 5.4 to 1390 mA. The purpose is to study the properties of the Z-, W- and Higgs boson and the top and anti-top quarks in four operation points. The beam current of 147 mA of the W working point requires particular care to string damp HOMs. This paper proposes 2-cell 400 MHz SRF cavities with improved damping as an alternative to the baseline 4-cell cavities for this working point. The resulting impedance of the HOM-damped cavity is then calculated and compared with the impedance budget.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK015  
About • Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 16 June 2022
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TUPOTK016 HiPIMS-Coated Novel S(I)S Multilayers for SRF Cavities SRF, niobium, target, cathode 1234
 
  • A.Ö. Sezgin, X. Jiang, M. Vogel
    University Siegen, Siegen, Germany
  • I. González Díaz-Palacio, R. Zierold
    University of Hamburg, Hamburg, Germany
  • S. Keckert, J. Knobloch, O. Kugeler, D.B. Tikhonov
    HZB, Berlin, Germany
  • J. Knobloch
    University of Siegen, Siegen, Germany
  • R. Ries, E. Seiler
    Slovak Academy of Sciences, Institute of Electrical Engineering, Bratislava, Slovak Republic
 
  Funding: Material syntheses and characterizations via SMART, BMBF, Germany (05K19PSA). Superconducting characterizations via iFAST, H2020, EU (101004730). Part of this work via the MNaF, University of Siegen.
Pushing beyond the existing bulk niobium SRF cavities is indispensable along the path towards obtaining more sustainable next generation compact particle accelerators. One of the promising candidates to push the limits of the bulk niobium is thin film-based multilayer structures in the form of superconductor-insulator-superconductor (SIS). In this work, S(I)S multilayer structures were coated by high power impulse magnetron sputtering (HiPIMS), having industrial upscaling potential along with provid-ing higher quality films with respect to conventional magnetron sputtering techniques (e.g., DCMS), combined with (PE)-ALD techniques for deposition of the ex-situ insulating layers. On the path towards formulating opti-mized recipes for these materials to be coated on the inner walls of (S)RF cavities, the research focuses on innovat-ing the best performing S(I)S multilayer structures con-sisting of alternating superconducting thin films (e.g., NbN) with insulating layers of metal nitrides (e.g., AlN) and/or metal oxides (e.g., AlxOy) on niobium lay-ers/substrates (i.e., Nb/AlN/NbN) in comparison to the so-called SS multilayer structures (i.e., Nb/NbN). This con-tribution presents the initial materials and superconduct-ing and RF characterization results of the aforementioned multilayer systems on flat samples.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK016  
About • Received ※ 11 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 18 June 2022
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TUPOTK018 Combined In-Situ QEXAFS and XRD Investigations on Nb-Treatments in N2 Gas Atmospheres at Elevated Temperatures vacuum, site, niobium, SRF 1238
 
  • P. Rothweiler, F. Eckelt, D. Lützenkirchen-Hecht, S. Paripsa, L. Voß
    University of Wuppertal, Wuppertal, Germany
 
  Funding: We gratefully acknowledge financial support by the German Federal Ministry of Education and Research (BMBF) under project No. 05H18PXRB1.
Thin polycrystalline Nb metal foils were treated in N2 gas atmospheres at elevated temperatures of 900 °C up to 1200 °C. A combination of transmission mode Quick X-ray absorption spectroscopy (QEXAFS) at the Nb-K-edge and X-ray diffraction (XRD) used in parallel were used to investigate changes in the atomic short and long-range structure of the bulk Nb-material in-situ. A dedicated high-vacuum heating cell with a base pressure of 10-6 mbar was used to perform the heat treatments under vacuum and nitrogen gas atmosphere. The treatments typically included (i) a preheating at 900 °C under high-vacuum, (ii) a treatment in 3 mbar nitrogen gas at the desired temperature and (iii) a cooldown to room temperature under vacuum conditions. The QEXAFS and XRD data were collected in parallel during the entire process with a time resolution of 4 s. While the samples treated at 900 °C show the typical N-uptake to the octahedral interstitial sites, the samples treated at higher temperatures show the growth of distinct niobium nitride phases. The results will be discussed in more details during the conference.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK018  
About • Received ※ 08 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 12 June 2022 — Issue date ※ 18 June 2022
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TUPOTK020 Status of LASA-INFN R&D Activity on PIP-II Low-beta Prototypes radiation, SRF, experiment, operation 1241
 
  • M. Bertucci, A. Bosotti, A. D’Ambros, E. Del Core, A.T. Grimaldi, P. Michelato, L. Monaco, C. Pagani, R. Paparella, D. Sertore
    INFN/LASA, Segrate (MI), Italy
  • A. Gresele
    Zanon Research & Innovation, Schio, VI, Italy
  • C. Pagani
    Università degli Studi di Milano & INFN, Segrate, Italy
 
  LASA-INFN is developing some PIP-II β=0.61 cavity prototypes so to set up a high-Q recipe allowing to reach the PIP-II performance target in view of the series production. A single-cell cavity was treated with a XFEL-like baseline recipe, whereas a multicell cavity underwent a mid-T bake step as final surface treatment. Both cavities have been then tested at the LASA vertical experimental facility. The test results are here reported and discussed. Basing on the satisfactory results so far obtained, a strategy for the qualification and upgrade of the LASA vertical test facility is outlined.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK020  
About • Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 16 June 2022
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TUPOTK021 Recent Update on ESS Medium Beta Cavities at INFN LASA SRF, operation, cryomodule, status 1245
 
  • D. Sertore, M. Bertucci, M. Bonezzi, A. Bosotti, D. Cardelli, A. D’Ambros, A.T. Grimaldi, L. Monaco, R. Paparella, G.M. Zaggia
    INFN/LASA, Segrate (MI), Italy
  • C. Pagani
    Università degli Studi di Milano & INFN, Segrate, Italy
 
  The INFN LASA contribution to the European Spallation Source ERIC (European Research Infrastructure Consortium) Superconducting Linac is focused on supplying 36 cavities for the Medium Beta section of the proton accelerator. Twenty eight cavities have been fully qualified and delivered to CEA for integration into the cryomodules. We present the status of the activities dedicated to completing our contribution both by applying alternative surface treatments with respect to the series vertical BCP and by procuring new cavities.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK021  
About • Received ※ 09 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 25 June 2022  
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TUPOTK022 INFN-LASA for the Fermilab PIP-II SRF, controls, linac, site 1249
 
  • R. Paparella, M. Bertucci, M. Bonezzi, A. Bosotti, D. Cardelli, A. D’Ambros, E. Del Core, A.T. Grimaldi, L. Monaco, D. Sertore, G.M. Zaggia
    INFN/LASA, Segrate (MI), Italy
  • C. Pagani
    Università degli Studi di Milano & INFN, Segrate, Italy
 
  The status of INFN-LASA contribution to the PIP-II project at Fermilab is reported in this paper. Experimental results and ongoing activities on prototypes are summarized together with the development of related testing infrastructures. The series production of the 38 5-cell, beta 0.61 cavities designed by INFN-LASA for the LB650 section of the PIP-II linac recently commenced, the status of major procurements and associated activities is here below presented. All cavities will be produced and surface treated in industry to reach the unprecedented performances required, qualified through vertical cold test at qualified infrastructures and delivered as linac-ready at the string assembly site.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK022  
About • Received ※ 09 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 04 July 2022
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TUPOTK023 Study on Commercial Diodes as Thermometers at Low Temperature for Temperature Mapping System of Nb3sn Superconducting Radiofrequency Cavities experiment, SRF, laser, controls 1252
 
  • R. Wanison, K. Umemori, T. Yamada
    KEK, Ibaraki, Japan
  • K. Takahashi
    Sokendai, Ibaraki, Japan
  • R. Wanison
    Department of Mechanical Engineering, Faculty of Engineering, Chiang Mai University, Chiang Mai, Thailand
 
  Nb3Sn Superconducting radiofrequency (SRF) cavities has been researched and developed at Center for Applied Superconducting Accelerator (CASA), KEK. One of effec-tive tools for research on the performance of SRF cavities is a temperature mapping (T-map) system for detecting small increases in temperature. It is a thermometer array positioned precisely on an outer surface of cavity wall. Thermometer should cover at least from the range of typi-cal operating temperature of 4 K to the transition tempera-ture of 18 K, for the Nb3Sn SRF cavities. Therefore, car-bon resistor can not be used as a cheap thermometer due to low sensitivity at this temperature range. In this pro-ceeding, we report the results of the test for various com-mercially available diodes as a thermometer for T-map system. The sensitivity, stability and the repeatability are measured, cooled by a GM cryocooler.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK023  
About • Received ※ 08 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 07 July 2022
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TUPOTK024 Multipacting Simulation on Half-Wave Resonator for 200 MeV Energy Upgrade of Komac Proton Linac simulation, multipactoring, electron, linac 1255
 
  • J.J. Dang, H.S. Kim, H.-J. Kwon, S. Lee
    KOMAC, KAERI, Gyeongju, Republic of Korea
 
  Funding: This work was supported through KOMAC operation fund of KAERI by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (KAERI-524320-22).
A superconducting linac is developed at KOrea Multi-purpose Accelerator Complex (KOMAC) for proton beam energy upgrade from 100 MeV to 200 MeV. The SRF linac consists of thirty-six half-wave resonator (HWR) cavities. 350 MHz, β = 0.56 HWR is designed to provide 3.6 MV accelerating voltage. After a fundamental RF design study, an analysis on a multipacting (MP) of HWR is carried out. The MP simulation for the HWR is performed by using CST Particle Studio. To understand a feature of the MP occurrence in the HWR, a particle-in-cell simulation is conducted while changing various conditions such as an RF amplitude, an RF phase, and an emission surface.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK024  
About • Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 04 July 2022
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TUPOTK025 Design Study of the Third Harmonic Superconducting Cavity for a Bunch Lengthening superconducting-cavity, status, vacuum, HOM 1258
 
  • J.Y. Yoon, E.-S. Kim
    KUS, Sejong, Republic of Korea
  • J.H. Han, H.S. Park
    Kiswire Advanced Technology Ltd., Daejeon, Republic of Korea
  • E. Kako
    KEK, Ibaraki, Japan
 
  The bunch lengthening by the 3rd harmonic cavity reduces the electron collisions in a bunch and increases the Touschek lifetime of a storage ring. We performed the multi-physics simulations including the electromagnetic, thermal, and mechanical analysis of the cavity. In the electromagnetic simulation, the geometry is optimized for the required performance of the cavity. The elliptical double-cell geometry is selected to increase the accelerating voltage and reduce the power losses of the cavity. Thermal/mechanical analyses were performed to check the deformation of the thermal and pressure contraction. The prototype cavity does not require the power coupler as it is a passive type. The conceptual design and copper prototype of the 3rd harmonic cavity will be described in this paper. Based on this design, the fabrication of Niobium cavity is in progress.
Superconducting RF, Cavity
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK025  
About • Received ※ 02 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 09 July 2022
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TUPOTK026 ESS Elliptical Cryomodules Tests at Lund Test Stand cryomodule, operation, vacuum, LLRF 1261
 
  • C.G. Maiano, E. Asensi Conejero, N. Elias, P. Goudket, W. Hees, P. Pierini, L. Sagliano, F. Schlander, M.Y. Wang
    ESS, Lund, Sweden
  • D. Bocian, W. Gaj, P. Halczynski, M. Sienkiewicz, F.D. Skalka, J. Swierblewski, K.M. Wartak, M. Wartak
    IFJ-PAN, Kraków, Poland
 
  We present an overview and description of the elliptical cryomodules test activities at Lund Test Stand 2. During 2021 the test facility was commissioned with one prototype, and four series medium beta modules have now been successfully tested at ESS in Lund. This activity allowed the joint ESS and IFJ PAN team to develop all the procedures and the necessary automated tools for the different phases of the site acceptance test campaign (e.g. incoming inspections, coupler conditioning, cooldown strategies, tuning to resonance and electromagnetic/cryogenic performance verification). During the initial test period techniques for diagnostics of limiting mechanisms have been developed and improved up to a consolidated and mature state for the rest of the test campaign. Tests results and the initial statistics is presented and commented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK026  
About • Received ※ 07 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 16 June 2022
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TUPOTK027 Field Emission Measurements at Lund Test Stand detector, cryomodule, shielding, SRF 1265
 
  • C.G. Maiano, N. Elias, E. Laface, P. Pierini, L. Sagliano, M.Y. Wang
    ESS, Lund, Sweden
  • E. Cenni
    CEA-IRFU, Gif-sur-Yvette, France
 
  We present here a description of field emission (FE) measurements set-up developed for elliptical cryomodules test activities at Lund Test Stand 2. A test campaign of field emission measurements has been developed and optimized during cryomodules tests. The scintillator detectors (and their respective shields), chosen for these measurements, have been characterized and optimized. The field emission application has been developed and integrated in the cryomodules tests operator interface. The Initial test results are presented and commented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK027  
About • Received ※ 07 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 10 July 2022
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TUPOTK028 Tuning of Superconducting Cavities Using the FFT of Transmitted Power klystron, resonance, operation, SRF 1268
 
  • E. Laface, C.G. Maiano, P. Pierini, M.Y. Wang
    ESS, Lund, Sweden
 
  We implemented a method to tune the ESS superconducting cavities based on the spectral analysis of the high resolution data available from the Low Level RF system (LLRF) for the transmitted power, without the need of connecting a network analyzer or any other dedicated instrumentation along the RF chain. A frequency peak up to 4 MHz off from the resonating frequency can be detected and used to control the stepper motor of the tuner until the cavity is stretched to the proper length to reach the correct operation frequency. Experience of its use at the ESS Test Stand 2 (TS2) facility at Lund during cryomodule acceptance testing is presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK028  
About • Received ※ 16 May 2022 — Revised ※ 11 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 14 June 2022
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TUPOTK029 Open XAL Status Report 2022 controls, linac, status, emittance 1271
 
  • A.P. Zhukov, A.M. Hoover, A.P. Shishlo
    ORNL, Oak Ridge, Tennessee, USA
  • J.F. Esteban Müller, E. Laface, Y. Levinsen, N. Milas
    ESS, Lund, Sweden
 
  The Open XAL accelerator physics software platform has been developed through international collaboration among several facilities since 2010. The goal of the collaboration is to establish Open XAL as a multi-purpose software platform supporting a broad range of tool and application development in accelerator physics and high-level control (Open XAL also ships with a suite of general-purpose accelerator applications). This paper discusses progress in beam dynamics simulation and updated application framework along with new generic accelerator physics applications. We present the status of the project at each participating facility and a roadmap for continued development.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK029  
About • Received ※ 09 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 29 June 2022
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TUPOTK031 A First 6 GHz Cavity Deposition with B1 Superconducting Thin Film at ASTeC SRF, target, controls, site 1279
 
  • R. Valizadeh, A.N. Hannah, O.B. Malyshev
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • E. Chyhyrynets, V.A. Garcia Diaz, C. Pira
    INFN/LNL, Legnaro (PD), Italy
  • V.R. Dhanak
    The University of Liverpool, Liverpool, United Kingdom
  • O.B. Malyshev
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • G.B.G. Stenning
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
 
  Nb3Sn, NbTiN and NbN are superconductors with critical temperatures of 18.3, 12.6-17 and 11.6-17.5 K, respectively, these are higher than that of Nb at 9.3 K. Hence, at 4 K, they have an RF resistance, an order of magnitude lower than that of Nb, which leads to quality factors above those of Nb. In recent years, there has been an extensive effort converting Nb cavities into Nb3Sn. Alloying the top inner layer of the cavity using Sn diffusion at a high temperature has had some degree of success, however, the reproducibility remains a major hindering and limiting factor. In this study, we report on the PVD deposition of NbTiN inside a 6 GHz cavity, using an external magnetic coil configuration. The deposition is done at an elevated temperature of about 650 C. We report on the superconducting properties, film structure and its stoichiometry and surface chemical state. The films have been characterised with SEM, XRD, XPS, EDS and SQUID magnetometer.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK031  
About • Received ※ 07 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 06 July 2022
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TUPOTK033 First RF Measurements of Planar SRF Thin Films with a High Throughput Test Facility at Daresbury Laboratory SRF, MMI, site, pick-up 1283
 
  • D.J. Seal, G. Burt, P. Goudket, O.B. Malyshev, B.S. Sian, R. Valizadeh
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • G. Burt, D.J. Seal, B.S. Sian
    Lancaster University, Lancaster, United Kingdom
  • P. Goudket, O.B. Malyshev, R. Valizadeh
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • P. Goudket
    ESS, Lund, Sweden
  • H.S. Marks
    Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
 
  The research on superconducting thin films for future radio frequency (RF) cavities requires measuring the RF properties of these films. However, coating and testing thin films on full-sized cavities is both challenging and timeconsuming. As a result, films are typically deposited on small, flat samples and characterised using a test cavity. At Daresbury Laboratory, a facility for testing 10 cm diameter samples has recently been commissioned. The cavity uses RF chokes to allow physical and thermal separation between itself and the sample under test. The facility allows for surface resistance measurements at a resonant frequency of 7.8 GHz, at temperatures down to 4 K, maximum RF power of 1 W and peak magnetic fields of a few mT. The main advantage of this system is the simple sample mounting procedure due to no physical welding between the sample and test cavity. This allows for a fast turnaround time of two to three days between samples. As such, this system can be used to quickly identify which samples are performing well under RF and should require further testing at higher gradient. Details of recent upgrades to this facility, together with measurements of both bulk niobium and thin film samples, will be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK033  
About • Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 30 June 2022 — Issue date ※ 02 July 2022
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TUPOTK034 Evaluating the Effects of Nitrogen Doping and Oxygen Doping on SRF Cavity Performance SRF, niobium, ECR, simulation 1287
 
  • H. Hu, Y.K. Kim
    University of Chicago, Chicago, Illinois, USA
  • D. Bafia
    Fermilab, Batavia, Illinois, USA
 
  Superconducting radiofrequency (SRF) cavities are resonators with extremely low surface resistance that enable accelerating cavities to have extremely high quality factors (Q0). High Q0 decreases the capital required to keep the accelerators cold by reducing power loss. The performance of SRF cavities is largely governed by the surface composition of the first §I{100}{nm} of the cavity surface. Impurities such as oxygen and nitrogen have been observed to yield high Q0, but their precise roles are still being studied. Here, we compare the performance of cavities doped with nitrogen and oxygen in terms of surface composition and heating behavior with field. A simulation of the diffusion of oxygen into the bulk of the cavity was built using COMSOL Multiphysics software. Simulated results were compared to the actual surface composition of the cavities as determined from secondary ion mass spectrometry analysis. Understanding how these impurities affects performance allows us to have further insight into the underlying mechanisms that enable these surface treatments to yield high Q0.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK034  
About • Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 12 June 2022 — Issue date ※ 30 June 2022
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TUPOTK035 CVD Nb3Sn-on-Copper SRF Accelerator Cavities SRF, niobium, radio-frequency, factory 1291
 
  • G. Gaitan, P.N. Koufalis, M. Liepe
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • V.M. Arrieta, S.R. McNeal
    Ultramet, Pacoima, California, USA
  • M. Liepe
    Cornell University, Ithaca, New York, USA
 
  Funding: This work is supported by the US Department of Energy SBIR program under grant number DE-SC0017902. Gabriel Gaitan is supported by the National Science Foundation under Grant No. PHY-1549132.
Nb3Sn is the most promising alternative material for achieving superior performance in Superconducting Radio-Frequency (SRF) cavities, compared to conventional bulk Nb cavities now used in accelerators. Chemical vapor deposition (CVD) is an alternative to the vapor diffusion-based Nb3Sn growth technique predominantly used on bulk niobium cavities and may enable reaching superior RF performance at reduced cost. In collaboration with Cornell, Ultramet has developed CVD process capabilities and reactor designs to coat copper SRF cavities with thick and thin films of Nb and Nb3Sn. In this paper, we present our latest research efforts on CVD Nb3Sn-on-copper SRF cavities, including RF performance test results from two 1.3 GHz SRF cavities coated by Ultramet.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK035  
About • Received ※ 15 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 21 June 2022
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TUPOTK036 Study of Chemical Treatments to Optimize Niobium-3 Tin Growth in the Nucleation Phase niobium, SRF, radio-frequency, site 1295
 
  • L. Shpani, S.G. Arnold, G. Gaitan, M. Liepe, Z. Sun
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • T. Arias, M.M. Kelley, N. Sitaraman
    Cornell University, Ithaca, New York, USA
 
  Funding: This research is funded by the National Science Foundation under Grant No. PHY-1549132, the Center for Bright Beams.
Niobium-3 Tin (Nb3Sn) is a high-potential material for next-generation Superconducting Radiofrequency (SRF) cavities in particle accelerators. The most promising growth method to date is based on vapor diffusion of tin into a niobium substrate with nucleating agent Tin Chloride (SnCl2). Still, the current vapor diffusion recipe has significant room for realizing further performance improvement. We are investigating how different chemical treatments on the niobium substrate before coating influence the growth of a smooth and uniform Nb3Sn layer. More specifically, this study focuses on the interaction between the SnCl2 nucleating agent and the niobium surface oxides. We compare the effect of different chemical treatments with different pH values on the tin droplet distribution on niobium after the nucleation stage of coating. We also look at the effect that the nucleation temperature has on the smoothness and uniformity of the tin distribution, with the ultimate goal of optimizing the recipe to coat smooth Nb3Sn cavities.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK036  
About • Received ※ 12 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 17 June 2022
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TUPOTK037 Status Update on Cornell’s SRF Compact Conduction Cooled Cryomodule cryomodule, SRF, operation, radio-frequency 1299
 
  • N.A. Stilin, A.T. Holic, M. Liepe, T.I. O’Connell, J. Sears, V.D. Shemelin, J. Turco
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
 
  A new frontier in Superconducting RF (SRF) development is increasing the accessibility of SRF technology to small-scale accelerator operations which are used in various industrial or research applications. This is made possible by using commercial cryocoolers as a cooling source, which removes the need for expensive liquid cryogenics and their supporting infrastructure. Cornell University is currently developing a new cryomodule based on a conduction cooling scheme. This cryomodule will use two pulse tube cryocoolers in place of liquid cryogenics in order to cool the system. A new 1.3 GHz cavity has been designed with a set of four niobium rings welded at the equator and irises which allow for a direct thermal link between the cavity and cryocooler cold heads. The cavity will use two coaxial RF input couplers capable of delivering up to 100 kW total RF power for high-current beam operation. This coupler design was modified from the Cornell ERL injector couplers, including simplifications such as removing the cold RF window and most outer bellows, while retaining inner bellows for adjustable coupling.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK037  
About • Received ※ 12 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 16 June 2022
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TUPOTK038 Next Generation SRF Cavities at Cornell University SRF, simulation, radio-frequency, accelerating-gradient 1303
 
  • N.M. Verboncoeur, M. Liepe, R.D. Porter, L. Shpani
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
 
  Our goal is to develop new materials and protocols for the growth and preparation of thin-film and layered superconductors for next generation SRF cavities with higher performance for future accelerators. We are working primarily with Nb3Sn to achieve this goal, as well as other materials which aim to optimize the RF field penetration layer of the cavity. This contribution gives a general update on our most recent cavity test results. A deeper insight into RF loss distribution and dynamics during cavity testing is gained using a new global high-speed temperature mapping system (T-Map).  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK038  
About • Received ※ 11 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 22 June 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPOTK040 Design of the Electron Ion Collider Electron Storage Ring SRF Cavity HOM, impedance, simulation, operation 1307
 
  • J. Guo, E. Daly, J. Henry, J. Matalevich, G.-T. Park, R.A. Rimmer, H. Wang, S. Wang
    JLab, Newport News, Virginia, USA
  • D. Holmes, K.S. Smith, W. Xu, A. Zaltsman
    BNL, Upton, New York, USA
 
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177
The Electron Ion Collider (EIC) under construction at Brookhaven National Laboratory is a high luminosity collider as the next major research facility for the nuclear physics community. Among the numerous RF subsystems in the EIC, the electron storage ring (ESR) fundamental RF cavities system is one of the most challenging. This system will handle a high beam current of up to 2.5 A and replenish up to 10 MW of beam power losses from synchrotron radiation and HOM. Variable coupling is required in the cavities due to the wide range of required total RF voltage and beam current combinations. In this paper, we will present the status of the design and future plans.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK040  
About • Received ※ 16 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 23 June 2022 — Issue date ※ 28 June 2022
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TUPOTK042 Challenges to Reliable Production Nitrogen Doping of Nb for SRF Accelerating Cavities niobium, SRF, vacuum, controls 1311
 
  • C.E. Reece, M.J. Kelley, E.M. Lechner, A.D. Palczewski
    JLab, Newport News, Virginia, USA
  • J.W. Angle, M.J. Kelley
    Virginia Polytechnic Institute and State University, Blacksburg, USA
  • F.A. Stevie
    NCSU AIF, Raleigh, North Carolina, USA
 
  Funding: This work was authored by JSA LLC under U.S. DOE contract DE-AC05-06OR23177. This material is based on work supported by the U.S. DOE Early Career Award to A. Palczewski, with supplemental support from DOE BES via the LCLS-II HE R&D program. J. Angle’s support was from the Office of High Energy Physics, under grant DE-SC-0014475 to Virginia Tech.
Over the last several years, alloying of the surface layer of niobium SRF cavities has been demonstrated to beneficially lower the superconducting RF surface resistance. Nitrogen, titanium, and oxygen have all been demonstrated as effective alloying agents, occupying interstitial sites in the niobium lattice within the RF penetration depth and even deeper, when allowed to thermally diffuse into the surface at appropriate temperatures. The use of nitrogen for this function has been often termed ’nitrogen doping’ and is being applied in the LCLS-II and LCLS-II HE projects. We report characterization studies of the distribution of nitrogen into the exposed niobium surface and how such distribution is affected by the quality of the vacuum furnace environment in which the doping takes place, and the complexity of nitride crystal growth on different grain orientations of surface niobium. Using state-of-the-art quantification methods by dynamic secondary ion mass spectrometry (SIMS) depth profiling in niobium, we identify several phenomena involving furnace-sourced contamination. We also highlight a potential issue with N2 flow constraints from the flange ’caps’ used during heat treatments.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK042  
About • Received ※ 07 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 05 July 2022
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TUPOTK044 Preliminary Results of a Magnetic and Temperature Map System for 3 GHz Superconducting Radio Frequency Cavities SRF, MMI, radio-frequency, niobium 1315
 
  • I.P. Parajuli, G. Ciovati, J.R. Delayen, A.V. Gurevich, B.D. Khanal
    ODU, Norfolk, Virginia, USA
  • G. Ciovati, J.R. Delayen
    JLab, Newport News, Virginia, USA
 
  Funding: Work supported by NSF Grant 100614-010. Jlab work is supported by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
Superconducting radio frequency (SRF) cavities are fundamental building blocks of modern particle accelerators. A surface resistance in the tens of nanoOhm range is achieved when cooling these cavities to liquid helium temperature, ~2 - 4 K. One of the leading sources of residual losses in SRF cavities is trapped magnetic flux. Flux trapping mechanism depends on different surface preparations and cool-down conditions. We have designed, developed and commissioned a combined magnetic and temperature mapping system using anisotropic magneto-resistance sensors and carbon resistors, respectively, to study the flux trap mechanism in 3 GHz single-cell niobium cavities. In this contribution, we will describe the experimental apparatus and present preliminary test results.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK044  
About • Received ※ 02 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 24 June 2022 — Issue date ※ 25 June 2022
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TUPOTK045 Magnetic Field Mapping of 1.3 GHz Superconducting Radio Frequency Niobium Cavities SRF, niobium, MMI, radio-frequency 1319
 
  • I.P. Parajuli, G. Ciovati, J.R. Delayen, A.V. Gurevich
    ODU, Norfolk, Virginia, USA
  • G. Ciovati, J.R. Delayen
    JLab, Newport News, Virginia, USA
 
  Funding: Work supported by NSF Grant 100614-010. Jlab work is supported by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
Niobium is the material of choice to build superconducting radio frequency (SRF) cavities, which are fundamental building blocks of modern particle accelerators. These cavities require a cryogenic cool-down to ~2 - 4 K for optimum performance minimizing RF losses on the inner cavity surface. However, temperature-independent residual losses in SRF cavities cannot be prevented entirely. One of the significant contributor to residual losses is trapped magnetic flux. The flux trapping mechanism depends on different factors, such as surface preparations and cool-down conditions. We have developed a diagnostic magnetic field scanning system (MFSS) using Hall probes and anisotropic magneto-resistance sensors to study the spatial distribution of trapped flux in 1.3 GHz single-cell cavities. The first result from this newly commissioned system revealed that the trapped flux on the cavity surface might redistribute with increasing RF power. The MFSS was also able to capture significant magnetic field enhancement at specific cavity locations after a quench.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK045  
About • Received ※ 02 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 20 June 2022 — Issue date ※ 27 June 2022
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TUPOTK048 Optimization of a 600 MHz Two-Cell Slotted Waveguide Elliptical Cavity for FCC-ee impedance, HOM, collider, GUI 1323
 
  • S. Gorgi Zadeh, O. Brunner, F. Peauger, I. Syratchev
    CERN, Meyrin, Switzerland
 
  The radio-frequency (RF) system of the future circular lepton collider (FCC-ee) must cope with different machine parameters ranging from Ampere-class operation required for the Z-peak working point to the high-gradient operation for the ttbar threshold. The Superconducting Slotted Waveguide Elliptical cavity (SWELL) concept was recently proposed as an alternative to the challenging RF baseline design of the FCC-ee. In this paper, random optimization methods are used to minimize the peak surface magnetic field and the maximum longitudinal impedance of the higher order modes (HOM) of a two-cell \unit[600]{MHz} SWELL cavity. In the next step, the waveguide slots are optimized to first have a smooth transition from the cavity to the slots to avoid large peak surface fields and second to achieve high transmission at dipole mode frequencies and low transmission at fundamental mode frequency while keeping the design compact.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK048  
About • Received ※ 23 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 15 June 2022
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TUPOTK049 Upgrade of ELSA’s Booster Synchrotron RF with a Solid State Power Amplifier synchrotron, controls, booster, operation 1327
 
  • M.T. Switka, K. Desch, D. Elsner, F. Frommberger, P. Hänisch
    ELSA, Bonn, Germany
 
  The 1.6 GeV booster synchrotron of the ELSA facility at the University of Bonn uses a DESY-type RF resonator which has been driven by a conventional klystron amplifier since its early days in 1967. The setup was modified to serve the ELSA stretcher ring as booster synchrotron in 1987, but the RF infrastructure was barely altered. As repairs of the reliable, but antiquated RF source became foreseeingly impossible due to the lack of spare part availability, the replacement of the klystron amplifier chain in favour of a state-of-the-art solid state amplifier was carried out. We describe the replacement and the operation experience with the new RF power amplifier.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK049  
About • Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 17 June 2022
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TUPOTK053 Design Progress of High Efficiency Klystron for CEPC LINAC klystron, simulation, gun, linac 1339
 
  • Z.D. Zhang, Y.L. Chi, D. Dong, M. Iqbal, G. Pei, S.C. Wang, O. Xiao, S. Zhang, Z.S. Zhou
    IHEP, Beijing, People’s Republic of China
  • S. Zhang, Z.D. Zhang
    UCAS, Beijing, People’s Republic of China
 
  The injector linear accelerator (LINAC) for the CEPC requires a higher efficiency klystron with 80MW output power than S band 65MW pulsed klys-tron currently operating in LINAC of BEPCII to reduce energy consumption and cost. The efficiency is ex-pected to improve from the currently observed 42% to more than 55% and output power will be improved from 65MW to more than 80MW with same operation voltage. In this paper, BAC bunching method is ap-plied for klystron efficiency improvement. The optimi-zation of the gun and solenoid parameters is complet-ed with 2-D code DGUN and then 3-D code CST. The preliminary design of the cavity parameters is also completed in 1-D disk model based AJDISK code and then further checked by 2-D code EMSYS. Finally, new klystron prototype will be fabricated in Chinese com-pany after design parameters are determined.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK053  
About • Received ※ 07 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 17 June 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPOTK054 Solid State Amplifiers for Beam Test System of PAPS at IHEP superconducting-cavity, SRF, operation, status 1342
 
  • O. Xiao, Y.L. Chi, N. Gan, X.P. Li, Z.D. Zhang
    IHEP, People’s Republic of China
 
  Solid state amplifiers are being increasingly used as RF power sources in accelerators around the world. Two solid state amplifiers with different output power and frequen-cy have been applied in beam test system of PAPS at IHEP. A 10kW solid state amplifier operating at 1.3 GHz is used to feed a normal conducting buncher. A 650 MHz solid state amplifier with the output power of 150 kW is used to feed two 2-cell superconducting cavities. So far, the debugging and acceptance test of solid state amplifi-ers have been finished. During the beam test system commissioning and operation, all solid state amplifiers operate stably. In this paper, the specifications and high power test results of solid state amplifiers are presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK054  
About • Received ※ 19 May 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 06 July 2022
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TUPOTK055 One Year of Operation of the New Wideband RF System of the Proton Synchrotron Booster MMI, operation, network, controls 1344
 
  • G.G. Gnemmi, S. Energico, M. Haase, M.M. Paoluzzi, C. Rossi
    CERN, Meyrin, Switzerland
 
  Within the LHC Injectors Upgrade project, the PS Booster(PSB) has been upgraded. Both the injection (160 MeV) and extraction (2 GeV) energies have been increased, bringing also changes in the injection beam revolution frequency, the maximum revolution frequency, and the beam intensity. To meet the requirements of the High Luminosity LHC a new RF system has been designed, based on the wideband frequency characteristics of Finemet® Magnetic Alloy and solid-state amplifiers. The wideband frequency response (1 MHz to 18 MHz) covers all the required frequency schemes in the PSB, allowing multi-harmonics operation. The system is based on a cellular configuration in which each cell provides a fraction of the total RF voltage. The new RF system has been installed in 3 locations replacing the old systems. The installation has been performed during 2019/2020, while the commissioning started later in 2020 and relevant results for the physics have been already observed. This paper describes the new RF chain, the results achieved and the issues that occurred during this year of operation, together with the changes made to the system to improve performance and reliability.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK055  
About • Received ※ 02 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 28 June 2022
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TUPOTK057 Innovative Magnetron Power Sources for Superconducting RF (SRF) Accelerators SRF, controls, operation, injection 1348
 
  • M.L. Neubauer, R.P. Johnson, R.R. Lentz, M. Popovic, T. Wynn
    Muons, Inc, Illinois, USA
  • R.A. Rimmer, H. Wang
    JLab, Newport News, Virginia, USA
 
  Funding: Work supported by DOE SBIR grant # DE-SC0022484
A magnetron suitable for 1497 MHz klystron replacements at Jefferson Lab will be constructed and tested with our novel patented subcritical voltage operation methods to drive an SRF cavity. The critical areas of magnetron manufacturing and design affecting life-cycle costs that will be modeled for improvement include: Qext, filaments, magnetic field, vane design, and novel control of outgassing. The most immediate benefit of this project is to make SRF accelerator projects more affordable for NP and other users of SRF Linacs. One of the most attractive commercial applications for SRF accelerators is to drive subcritical nuclear reactors to burn Light Water Reactor Spent Nuclear Fuel (LWR SNF). A 1 GeV proton beam hitting an internal uranium spallation neutron target can produce over 30 neutrons for each incident proton to allow the reactor to operate far below criticality to generate electricity or process heat while reducing high-level waste disposal costs. This commercial application has the additional attribute of addressing climate change.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK057  
About • Received ※ 09 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 09 July 2022
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TUPOTK058 Development and Testing of High Power CW 1497 MHz Magnetron cathode, electron, power-supply, simulation 1351
 
  • M. Popovic, M.A. Cummings, A. Dudas, R.P. Johnson, R.R. Lentz, M.L. Neubauer, T. Wynn
    Muons, Inc, Illinois, USA
  • T. Blassick, J.K. Wessel
    Richardson Electronics Ltd, Lafox, Illinois, USA
  • K. Jordan, R.A. Rimmer, H. Wang
    JLab, Newport News, Virginia, USA
 
  Funding: Work supported by DOE NP STTR grant DE-SC0013203
We have designed, built, and tested a new magnetron tube that generates RF power at 1497 MHz. In the tests so far, the tube has produced CW 9 kW RF power, where the measured power is limited by the test equipment. The final goal is to use it to power superconducting (SC) cavities.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK058  
About • Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 27 June 2022 — Issue date ※ 06 July 2022
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TUPOTK059 Modeling O and N Alloying in Nb for SRF Applications SRF, niobium, radio-frequency, vacuum 1354
 
  • E.M. Lechner, M.J. Kelley, A.D. Palczewski, C.E. Reece
    JLab, Newport News, Virginia, USA
  • J.W. Angle, M.J. Kelley
    Virginia Polytechnic Institute and State University, Blacksburg, USA
  • F.A. Stevie
    NCSU AIF, Raleigh, North Carolina, USA
 
  Funding: This work was coauthored by Jefferson Science Associates LLC under U.S. DOE Contract No. DE-AC05-06OR23177 and grant No. DE-SC-0014475 to Virginia Tech for the support of J. Angle.
N and O-alloyed superconducting radio frequency cavities exhibit extraordinary quality factors. Developing diffusion models that describe interstitial N and O in Nb is important for optimizing alloyed cavity quality factors and accelerating gradients. N and O-alloyed Nb samples are examined with SEM AND SIMS and their diffusion profiles modeled.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK059  
About • Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 17 June 2022
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TUPOTK064 HL-LHC Crab Cavity HOM Couplers: Challenges and Results HOM, impedance, simulation, cryomodule 1374
 
  • J.A. Mitchell, R. Calaga, E. Montesinos
    CERN, Meyrin, Switzerland
 
  To compensate for the detrimental effect of the crossing angle on luminosity production in the High Luminosity Large Hadron Collider’s (HL-LHC) interaction regions, superconducting crab cavities (vertical and horizontal) will be installed at the two interaction regions of the ATLAS and CMS experiments. Both cavity designs use multiple Higher Order Mode (HOM) couplers to reduce beam instabilities and heat loads caused by the very high proton current in the HL-LHC. The conceptual RF designs of the HOM couplers are firstly presented, evaluating HOM damping requirements, fundamental mode rejection and dynamic heat load constraints. A special focus is given to the coupler’s characteristic impedance (Z0), to improve the robustness during transport and operation. Following this, RF measurements of the HOM couplers before installation, installed on the superconducting cavities and with a circulating proton beam are detailed, analysing deviations from the simulated cases.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK064  
About • Received ※ 07 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 10 July 2022
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TUPOTK065 Design of a Passive Superconducting Harmonic Cavity for HALF Storage Ring storage-ring, HOM, cryomodule, impedance 1378
 
  • Y. Wei, B. Du, G. Feng, D. Jia, J. Pang, S.C. Zhang
    USTC/NSRL, Hefei, Anhui, People’s Republic of China
  • C.P. Welsch, H.D. Zhang
    The University of Liverpool, Liverpool, United Kingdom
  • C.P. Welsch, H.D. Zhang
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
 
  Higher harmonic cavities, also known as Landau cavities, have been proposed to improve beam lifetime and provide Landau damping by lengthening the bunch without energy spread for stable operations of present and future low-emittance storage rings. This contribution presents design of a passive superconducting 3rd-harmonic cavity (super-3HC) for the planned Hefei Advanced Light Facility (HALF) at University of Science and Technology of China. It is designed to provide 0.43 MV at 1499.4 MHz for the nominal 2.2 GeV, 350 mA electron beam, and 1.44 MV main RF voltage in storage ring. Through optimizations it has a low R/Q < 45 Ohm, which has potential to achieve a good bunch lengthening. Higher-order-modes are strongly damped using a pair of room-temperature silicon carbide (SiC) rings to meet the requirement of beam instabilities. In addition, preliminary engineering design for the super-3HC cryomodule is also described in this contribution.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK065  
About • Received ※ 03 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 17 June 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPOMS002 Status of Sirius Operation storage-ring, operation, MMI, emittance 1385
 
  • L. Liu, M.B. Alves, A.C.S. Oliveira, X.R. Resende, R.M. Seraphim, H. Westfahl Jr., F.H. de Sá
    LNLS, Campinas, Brazil
  • R.H.A. Farias, S.R. Marques
    CNPEM, Campinas, SP, Brazil
 
  SIRIUS is a Synchrotron Light Source Facility based on a 3 GeV electron storage ring with 518 m circumfer-ence and 250 pm.rad emittance. The facility was built and is operated by the Brazilian Synchrotron Light Laboratory (LNLS), located in the CNPEM campus, in Campinas, Brazil. The accelerator commissioning and operation has been split into 2 phases: Phase0, corresponding to the initial accelerator commissioning with 6 beamlines, has been completed, and the project is now in preparation for Phase1, with full accelerator design performance and 14 beamlines in operation. We report on the status of SIRI-US last year operation and ongoing activities towards achieving completion of Phase1.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS002  
About • Received ※ 08 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 29 June 2022  
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TUPOMS003 CLS Operational Status and Future Operational Plans operation, linac, storage-ring, booster 1389
 
  • M.J. Boland, F. Le Pimpec
    CLS, Saskatoon, Saskatchewan, Canada
 
  The Canadian Light Source (CLS) has been in operation for users since 2005 and recently commissioned the 22nd photon beamline. In 2021 the CLS commenced top-up operations at 220 mA, which has been a big success for the user experiments. The storage ring is now RF power limited and will require a second RF cavity to realise the design goal of 500 mA. The 250 MeV electron injector complex for the CLS booster synchrotron ring dates back to the original linac from 1962 and the Saskatchewan Accelerator Laboratory. This paper will give an overview of the present status of the accelerator systems for user operations and the operational improvement plans for a second RF cavity in the storage ring and a new linac.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS003  
About • Received ※ 16 June 2022 — Revised ※ 18 June 2022 — Accepted ※ 23 June 2022 — Issue date ※ 28 June 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPOMS009 First Year of Operation of the ESRF-EBS Ligth Source operation, SRF, injection, emittance 1413
 
  • J.-L. Revol, C. Benabderrahmane, P.B. Borowiec, E. Buratin, N. Carmignani, L.R. Carver, A. D’Elia, M. Dubrulle, F. Ewald, A. Franchi, G. Gautier, L. Hardy, L. Hoummi, J. Jacob, L. Jolly, G. Le Bec, I. Leconte, S.M. Liuzzo, M. Morati, T.P. Perron, Q. Qin, B. Roche, K.B. Scheidt, V. Serrière, R. Versteegen, S.M. White
    ESRF, Grenoble, France
 
  The European Synchrotron Radiation Facility - Extremely Brilliant Source (ESRF-EBS) is a facility upgrade allowing its scientific users to take advantage of the first high-energy 4th generation light source. In December 2018, after 30 years of operation, the beam stopped for a 12-month shutdown to dismantle the old storage ring and to install the new X-ray source. On 25 August 2020, the user programme was restarted with beam parameters very close to nominal values. This paper reports on the present operation performance of the source, highlighting the ongoing and planned development.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS009  
About • Received ※ 08 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 06 July 2022
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TUPOMS023 The Elettra 2.0 Project insertion, insertion-device, emittance, operation 1459
 
  • E. Karantzoulis, A. Fabris, S. Krecic
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
 
  The project status of the future Italian 2.4 GeV fourth generation light source Elettra 2.0 that will replace the third-generation light source Elettra is presented. Elettra 2.0 will be the ultra-low emittance light source that will provide ultra-high brilliance and coherence and at the same time aims to provide very short pulses for time resolved experiments.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS023  
About • Received ※ 23 May 2022 — Revised ※ 13 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 23 June 2022
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TUPOMS027 ALBA II Acelerator Upgrade Project emittance, lattice, storage-ring, injection 1467
 
  • F. Pérez, I. Bellafont, G. Benedetti, J. Campmany, M. Carlà, J.J. Casas, C. Colldelram, F.F.B. Fernández, J.C. Giraldo, T.F. Günzel, U. Iriso, J. Marcos, Z. Martí, V. Massana, R. Muñoz Horta, M. Pont, L. Ribó, P. Solans, L. Torino
    ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
 
  ALBA is working on the upgrade project that shall transform the actual storage ring, in operation since 2012, into a 4th generation light source, in which the soft X-rays part of the spectrum shall be diffraction limited. The project has been officially launched in 2021 and a White Paper presenting the main concepts of the upgrade has been published in Spring 2022. The storage ring upgrade is based on a 6BA lattice which has to comply with several constraints imposed by the decision of maintaining the same circumference (269 m), the same number of cells (16), the same beam energy (3 GeV), and as many of the source points as possible unperturbed. The lattice optimization has achieved an emittance of 140 pm.rad, which is a factor 30 smaller than that of the existing ring, but with an array compactness that presents technological challenges for the magnets, vacuum, diagnostics, RF systems and injection elements designs that are being investigated through an intensive R&D program.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS027  
About • Received ※ 06 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 23 June 2022
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TUPOMS028 3HC - Third Harmonic Normal Conducting Active Cavity Collaboration Between HZB, DESY and ALBA HOM, impedance, simulation, storage-ring 1471
 
  • F. Pérez, J.R. Ocampo, A. Salom, P. Solans
    ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
  • W. Anders, V. Dürr, T. Loewner, A.N. Matveenko, M. Ries, L. Shi, Y. Tamashevich, A.V. Tsakanian
    HZB, Berlin, Germany
  • M. Ebert, R. Onken
    DESY, Hamburg, Germany
  • P. Hülsmann
    GSI, Darmstadt, Germany
  • W.F.O. Müller
    TEMF, TU Darmstadt, Darmstadt, Germany
 
  Funding: Co-funded by the European Regional Development Fund (ERDF)
A collaboration agreement between the HZB, DESY and ALBA institutions was signed on 2021 in order to test the 3rd harmonic normal conducting, HOM damped, active cavity designed and prototyped by ALBA*. The test will involve low power characterization of the fundamental mode, bead pull measurements to fully determine the HOM characteristics, a full high power conditioning to validate the power capability of the cavity, and finally, the installation of the cavity in the BESSY II storage ring in order to test the cavity in real conditions with beam. In this paper the low power, bead pull and conditioning results will be presented. The cavity has been installed at BESSY II on May 2022 to be tested after the summer shutdown.
* Prototype fabrication of an active normal conducting third harmonic cavity for the ALBA Storage Ring. J.Ocampo et al. , IPAC 2022 proceedings.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS028  
About • Received ※ 06 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 02 July 2022
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TUPOMS029 Status of the PETRA IV Machine Project alignment, dipole, operation, emittance 1475
 
  • R. Bartolini, I.V. Agapov, A. Aloev, R. Bacher, R. Böspflug, H.-J. Eckoldt, J. Hauser, M. Hüning, P. Hülsmann, N. Koldrack, B. Krause, L. Lilje, G. Loisch, R. Onken, A. Petrov, S. Pfeiffer, J. Prenting, H. Schlarb, M. Thede, M. Tischer
    DESY, Hamburg, Germany
 
  DESY is planning the upgrade of PETRA III to a fourth generation light source, providing high brightness, quasi diffraction limited hard X-ray photons. The project is underpinned by the construction of a new storage ring PETRA IV, based on a 20 pm accelerator lattice using a hybrid 6-bend achromat concept. We review here the status of the machine project, the latest development in the different technical subsystems, the status of the engineering integration and the plans for the implementation of the new ring in the existing PETRA III tunnel.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS029  
About • Received ※ 14 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 21 June 2022
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TUPOMS031 Fill Pattern for Reducing Transient Beam Loading and Ion-Trapping in the Diamond-II Storage Ring simulation, storage-ring, beam-loading, emittance 1483
 
  • T. Olsson, H.C. Chao
    DLS, Oxfordshire, United Kingdom
 
  The Diamond-II upgrade will replace the existing Diamond storage ring with a multibend achromat lattice providing higher brightness to the users by reducing the emittance and increasing the beam energy. The new storage ring will require a harmonic cavity that lengthens the bunches to increase the Touschek lifetime as well as mitigate instabilities and suppress the emittance blow up from intrabeam scattering. It is expected that the ring will have to operate with gaps in the fill pattern for ion-clearing, but that will lead to transient beam loading resulting in reduced bunch lengthening. The length and occurrence of the gaps therefore have to be determined as a trade-off between the requirements for transient beam loading and ion-trapping. This paper presents simulations of both effects for the Diamond-II storage ring to find an optimal fill pattern.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS031  
About • Received ※ 07 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 24 June 2022
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TUPOMS038 RFQ NEWGAIN: RF and Thermomechanical Design rfq, linac, proton, insertion 1510
 
  • P. Hamel, N. Sellami
    CEA-IRFU, Gif-sur-Yvette, France
  • M.J. Desmons, O. Piquet, B. Prevet
    CEA-DRF-IRFU, France
 
  Funding: Agence Nationale de la Recherche (ANR)
A new injector called NEWGAIN will be added to the SPIRAL2 Linear Accelerator (LINAC), in parallel with the existing one. It will be mainly composed of an ion source and a Radio Frequency Quadrupole (RFQ) connected to the superconductive LINAC of SPIRAL2. The new RFQ will accelerate at 88.05 MHz particles with charge-over-mass ratio (Q/A) between 1/3 and 1/7, from 10 keV/u up to 590 keV/u. It consists of a 4-vane resonant cavity with a total length of 7 m. It is a CW machine that has to show stable operation, provide the request availability, have the minimum losses in order to provide the highest current to the superconductive LINAC and show the best quality/cost ratio. This paper will present the preliminary RF design and the thermomechanical study for this RFQ.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS038  
About • Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 27 June 2022
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TUPOMS040 Characterization of Higher-Order-Modes (HOM) in THOMX Storage Ring RF Cavity HOM, controls, storage-ring, impedance 1513
 
  • M. El Khaldi, J-N. Cayla, H. Monard
    Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
  • M. Diop, F. Ribeiro
    SOLEIL, Gif-sur-Yvette, France
 
  The RF system of the ThomX storage ring consists in a 500 MHz single cell copper cavity of the ELETTRA type, powered with a 50 kW CW solid state amplifier, and the associated Low-Level RF feedback and control loops. The low operating energy of 50-100 MeV makes the impedances of the cavity higher order modes (HOMs) particularly critical for the beam stability. Their parasitic effects on the beam can be cured by HOM frequency shifting techniques, based on a fine temperature tuning and a dedicated adjustable plunger. A cavity temperature stability of ± 0.1 °C within a range from 30 up to 70 °C is achieved by a precise control of its water-cooling temperature. On the other hand, the tuning of the cavity fundamental mode is achieved by changing its axial length by means of a mechanical tuner. In order to insure a fine control of the HOM frequencies, a good knowledge of their characteristics is mandatory. The main parameters of the fundamental and of the HOMs up to 2.2 GHz versus temperature have been measured at low power using a vector network analyzer (VNA).  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS040  
About • Received ※ 03 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 12 June 2022 — Issue date ※ 21 June 2022
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TUPOMS041 High Power RF-Cavity Development for the HBS-Driver LINAC heavy-ion, neutron, linac, operation 1516
 
  • M. Basten, K. Aulenbacher, W.A. Barth, C. Burandt, F.D. Dziuba, V. Gettmann, T. Kürzeder, S. Lauber, J. List, M. Miski-Oglu, M. Vossberg, S. Yaramyshev
    GSI, Darmstadt, Germany
  • K. Aulenbacher, W.A. Barth, M. Basten, C. Burandt, F.D. Dziuba, V. Gettmann, T. Kürzeder, S. Lauber, J. List, M. Miski-Oglu
    HIM, Mainz, Germany
  • K. Aulenbacher, W.A. Barth, F.D. Dziuba, S. Lauber, J. List
    KPH, Mainz, Germany
  • T. Gutberlet
    JCNS, Jülich, Germany
  • H. Podlech
    IAP, Frankfurt am Main, Germany
  • H. Podlech
    HFHF, Frankfurt am Main, Germany
 
  Neutron research in Europe is mainly based on various nuclear reactors that will be successively decommissioned over the next years. This means that despite the commissioning of the European Spallation Source ESS, many neutron research centres, especially in the medium flux regime, will disappear. In response to this situation, the Jülich Centre for Neutron Science (JCNS) has begun the development of a scalable, compact, accelerator-based High Brilliance neutron Source (HBS). A total of three different neutron target stations are planned, which can be operated with a 100 mA proton beam of up to 70 MeV and a duty cycle of up to 6%. The driver Linac consists of an Electron Cyclotron Resonance (ECR) ion source followed by a LEBT section, a 2.5 MeV double Radio-Frequency Quadrupole (RFQ) and 35 normal conducting (NC) Crossbar H-Mode (CH) cavities. The development of the cavities is carried out by the Institute for Applied Physics (IAP) at the Goethe University Frankfurt am Main. Due to the high beam current, all cavities as well as the associated tuners and couplers have to be optimised for operation under high thermal load to ensure safe operation. In collaboration with the GSI Centre for Heavy Ion Research as the ideal test facility for high power tests, two cavities and the associated hardware are being designed and will be tested. The design and latest status of both cavities will be presented in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS041  
About • Received ※ 18 May 2022 — Revised ※ 15 June 2022 — Accepted ※ 28 June 2022 — Issue date ※ 06 July 2022
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TUPOMS042 Cavity R&D for HBS Accelerator simulation, neutron, brilliance, proton 1520
 
  • N.F. Petry, K. Kümpel, S. Lamprecht, O. Meusel, H. Podlech, M. Schwarz
    IAP, Frankfurt am Main, Germany
 
  The demand for neutrons of various types for research is growing day by day worldwide. To meet the growing demand the Jülich High Brilliance Neutron Source (HBS) is in development. It is based on a high power linear proton accelerator with an end energy of 70 MeV and a proton beam current of 100 mA. After the injector and the MEBT is the main part of the accelerator, which consists of about 36 CH-type cavities. The design of the CH-type cavities will be optimized in terms of required power, required cooling and reliability and the recent results will be presented in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS042  
About • Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 15 June 2022
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TUPOMS045 Design Validation of High Current Injector Facility at IUAC DELHI DTL, rfq, acceleration, diagnostics 1530
 
  • R.V. Hariwal, R. Ahuja, P. Barua, R.K. Gurjar, S. Kedia, A. Kothari, A. Kumar, M. Kumar, P. Kumar, R. Kumar, R. Kumar, S. Kumar, S. Kumar, P.S. Lakshmy, K. Mal, A.J. Malyadri, Y.M. Mathur, R. Mehta, DK. Munda, U.G. Naik, C. Pal, U.K. Rao, G.O. Rodrigues, C.P. Safvan, A. Sarkar, V.V.V. Satyanarayana, K. Singh, P. Singh, S.K. Sonti, S.K. Suman, T. Varughese, S.R. Venkataramanan, J. Zacharias
    IUAC, New Delhi, India
 
  High Current Injector (HCI) is an upcoming heavy ion accelerator facility at Inter-University Accelerator Centre (IUAC), New Delhi, INDIA and it will serve as an alternate injector to the existing Superconducting Linear Accelerator. HCI is designed to achieve the maximum energy gain of 1.8 MeV/u for the ions, including the Noble gasses and metallic ions, having A/q less than equal to 6. It consists of an 18 GHz High Temperature Superconducting Electron Cyclotron Resonance Ion Source, Multi-harmonic Buncher, Radio Frequency Quadrupole (RFQ), Spiral Buncher and six interdigital H-mode Drift Tube Linac (IH-DTL) cavities operating at 97 MHz resonant frequency. The RFQ accelerates the ions from 8 keV/u to 180 keV/u energy and the six DTL cavities are used to achieve the maximum energy gain of 1.8 MeV/u. Recently, the bunched beam of N5+ was successfully accelerated through RFQ and six IH-DTL cavities and we achieved the designed energy, which is an important milestone of this project. These results validate the design parameters of all RF cavities, accelerating to achieve the designed energy goal of 1.8 MeV/u. Here, present status and future plans of the project shall be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS045  
About • Received ※ 12 June 2022 — Revised ※ 17 June 2022 — Accepted ※ 30 June 2022 — Issue date ※ 05 July 2022
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TUPOMS046 Fabrication and Low-Power Test of Disk-and-Washer Cavity for Muon Acceleration experiment, linac, acceleration, dipole 1534
 
  • Y. Takeuchi, J. Tojo
    Kyushu University, Fukuoka, Japan
  • E. Cicek, H. Ego, K. Futatsukawa, N. Kawamura, T. Mibe, M. Otani, N. Saito, T. Yamazaki, M. Yoshida
    KEK, Ibaraki, Japan
  • Y. Iwashita
    Kyoto University, Research Reactor Institute, Osaka, Japan
  • R. Kitamura, T. Morishita
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  • Y. Kondo
    JAEA, Ibaraki-ken, Japan
  • Y. Nakazawa
    Ibaraki University, Hitachi, Ibaraki, Japan
  • Y. Sue, K. Sumi, M. Yotsuzuka
    Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan
  • H.Y. Yasuda
    University of Tokyo, Tokyo, Japan
 
  The muon g-2/EDM experiment is under preparation at Japan Proton Accelerator Research Complex (J-PARC), and the muon linear accelerator for the experiment is being developed. A Disk-and-Washer (DAW) cavity will be used for the medium-velocity part of the accelerator, and muons will be accelerated from v/c=ß=0.3 to 0.7 with the operating frequency of 1.296 GHz. Machining, brazing, and low-power measurements of a prototype cell reflecting the design of the first tank of DAW were performed to identify fabrication problems. Several problems were identified, such as displacement of washers during brazing, and some measures will be taken in the actual tank fabrication. In this paper, the results of the prototype cell fabrication will be reported.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS046  
About • Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 23 June 2022
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TUPOMS049 Digital LLRF for the Canadian Light Source LLRF, booster, controls, operation 1538
 
  • P. Solans, F. Pérez, A. Salom
    ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
  • D.R. Beauregard, C.J. Boyle, J.M. Patel, H. Shaker, J. Stampe
    CLS, Saskatoon, Saskatchewan, Canada
 
  The Canadian Light Source, at the University of Saskatchewan, is a 3rd generation synchrotron light source located in the city of Saskatoon, Canada. The facility comprises a 250 MeV LINAC, a full energy booster and a 2.9 GeV storage ring. The radiofrequency system in the booster consist of two 5-cell cavities feed with a single SSPA. The analogue LLRF for the booster has been recently replaced by a digital LLRF based in the ALBA design with a Picodigitizer, a stand-alone commercial solution provided by Nutaq. Also, the firmware of the new DLLRF is configurable to allow operation with a superconducting cavity feed with one amplifier, thus providing the possibility to replace the CLS SR LLRF as well. The main hardware components, the basic firmware functionalities and the commissioning measurements of the new DLLRF for the CLS booster will be presented in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS049  
About • Received ※ 08 June 2022 — Accepted ※ 11 June 2022 — Issue date ※ 30 June 2022  
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TUPOMS051 Prototype Fabrication of an Active Normal Conducting Third Harmonic Cavity for the ALBA Storage Ring HOM, GUI, simulation, storage-ring 1542
 
  • J.R. Ocampo, J.M. Álvarez, B. Bravo, F. Pérez, A. Salom, P. Solans
    ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
 
  Funding: Co-funded by the European Regional Development Fund (ERDF)
ALBA has designed a normal conducting active 1.5 GHz HOM damped cavity for the active third harmonic RF system for the ALBA Storage Ring (SR), which also will serve for the upgraded ALBA II. The third harmonic cavity at ALBA will be used to increase the bunch length in order to improve the beam lifetime and increase the beam stability thresholds. A prototype has been constructed by the company AVS in collaboration with VITZRO. This paper presents the design of the cavity, the constructed prototype, the Acceptance Tests measurements, and the future plans.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS051  
About • Received ※ 07 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 30 June 2022 — Issue date ※ 01 July 2022
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TUPOMS054 Data Augmentation for Breakdown Prediction in CLIC RF Cavities operation, network, experiment, ECR 1553
 
  • H.S. Bovbjerg, M. Shen, Z.H. Tan
    Aalborg University, Aalborg, Denmark
  • A. Apollonio, H.S. Bovbjerg, T. Cartier-Michaud, W.L. Millar, C. Obermair, D. Wollmann
    CERN, Meyrin, Switzerland
  • C. Obermair
    TUG, Graz, Austria
 
  One of the primary limitations on the achievable accelerating gradient in normal-conducting accelerator cavities is the occurrence of vacuum arcs, also known as RF breakdowns. A recent study on experimental data from the CLIC XBOX2 test stand at CERN proposes the use of supervised machine learning methods for predicting RF breakdowns. As RF breakdowns occur relatively infrequently during operation, the majority of the data was instead comprised of non-breakdown pulses. This phenomenon is known in the field of machine learning as class imbalance and is problematic for the training of the models. This paper proposes the use of data augmentation methods to generate synthetic data to counteract this problem. Different data augmentation methods like random transformations and pattern mixing are applied to the experimental data from the XBOX2 test stand, and their efficiency is compared.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS054  
About • Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 15 June 2022
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TUPOMS057 Design Study of HOM Couplers for the C-Band Accelerating Structure factory, GUI, damping, dipole 1561
 
  • D. Kim, E.I. Simakov
    LANL, Los Alamos, New Mexico, USA
  • S. Biedron
    UNM-ECE, Albuquerque, USA
  • Z. Li
    SLAC, Menlo Park, California, USA
 
  Funding: High Energy Physics (HEP) at the U.S. Department of Energy (DOE)
A cold copper distributed coupling accelerator, with a high accelerating gradient at cryogenic temperatures (~77 K), is proposed as a baseline structure for the next generation of linear colliders. This novel technology improves accelerator performance and allows more degrees of freedom for optimization of individual cavities. It has been suggested that C-band accelerating structures at 5.712 GHz may allow to maintain high efficiency, achieve high accelerating gradient, and be suitable beam dynamics with wakefield damping and detuning of the cavities. The optimization of the cavity shape was performed and we computed quality factor, shunt impedance, and beam kick factor for each of the proposed cavity geometries using CST microwave studio. Next, we proposed a configuration for higher order mode (HOM) suppression that includes waveguide slots running parallel to the axis of the accelerator. This presentation will report details of the parametric study of performance of the HOM suppression waveguide, and the dependence of HOM Q-factors and kick-factors on the cavity’s and HOM waveguide’s geometries.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS057  
About • Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 09 July 2022
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TUPOMS058 C-Band High Gradient Testing of the Benchmark a/λ=0.105 Cavity GUI, coupling, klystron, electron 1564
 
  • E.I. Simakov, V. Gorelov, T. Tajima, M.R.A. Zuboraj
    LANL, Los Alamos, New Mexico, USA
  • S. Biedron
    Element Aero, Chicago, USA
  • S. Biedron
    UNM-ECE, Albuquerque, USA
  • M.E. Middendorf
    ORNL RAD, Oak Ridge, Tennessee, USA
 
  Funding: Los Alamos National Laboratory LDRD Program
This poster will report the results of high gradient testing of the benchmark C-band RF cavity. Modern applications such as X-ray sources require accelerators with optimized cost of construction and operation, naturally calling for high-gradient acceleration. At LANL we commissioned a test stand (CERF-NM) powered by a 50 MW, 5.712 GHz Canon klystron. The test stand is capable of conditioning accelerating cavities for operation at surface electric fields in excess of 300 MV/m. CERF-NM is the first high gradient C-band test facility in the United States. An important milestone for this test stand is to demonstrate conditioning and high gradient testing of the most basic high gradient RF cavity with a geometry that has been extensively studied at other frequencies, such as X-band. The cavity is the three-cell structure with the highest gradient in the central cell and two coupling cells, and the ratio of the radius of the coupling iris to the wavelength a/\lamda=0.105. This presentation will report achieved gradients, breakdown probabilities, and other characteristics measured during the high power operation of this cavity.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS058  
About • Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 17 June 2022
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TUPOMS060 High Gradient Conditioning and Performance of C-Band ß=0.5 Proton Normal- Conducting Copper and Copper-Silver Radio-Frequency Accelerating Cavities proton, operation, klystron, coupling 1567
 
  • M.R.A. Zuboraj, R.L. Fleming, V. Gorelov, J.W. Lewellen, M.E. Middendorf, E.I. Simakov
    LANL, Los Alamos, New Mexico, USA
  • S.V. Baryshev, M.E. Schneider
    Michigan State University, East Lansing, Michigan, USA
  • V.A. Dolgashev, E.A. Nanni, E.J.C. Snively, S.G. Tantawi
    SLAC, Menlo Park, California, USA
  • E. Jevarjian
    MSU, East Lansing, Michigan, USA
 
  Funding: LANL-LDRD
This work presents the results of high gradient testing of the two C-band (5.712 GHz) normal conducting ß=0.5 accelerating cavities. The first cavity was made of copper and second was made of copper-silver alloy with 0.08% silver concentration. The tests were conducted at the C-Band Engineering Research Facility of New Mexico (CERF-NM) located at Los Alamos National Laboratory Both cavities achieved gradients in excess of 200 MV/m and surface electric fields in excess of 300 MV/m. The breakdown rates were mapped as functions of the gradient and peak surface fields. The gradients and peak surface fields observed in the copper-silver cavity were about 20% higher than those in the pure copper cavity with the same breakdown rate. It was concluded that the dominant breakdown mechanism in these cavities was not the pulse heating but the breakdown due to very high surface electric fields.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS060  
About • Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 19 June 2022
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TUPOMS061 RF System Design for Elettra 2.0 storage-ring, operation, HOM, booster 1570
 
  • C. Pasotti, M. Bocciai, L. Bortolossi, M. Rinaldi
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
 
  The Elettra 2.0 low emittance light source project aims to a substantial increase of the brilliance and coherence fraction of the source improving, at the same time, the storage ring stability and reliability. The Radio Frequency (RF) system plays a pivotal role in the beam quality, stability and reliability for the user operation. This paper will cover the design and the implemented strategy to meet these features for the Elettra 2.0 RF system. Starting point of the new RF design is the final choice of the RF frequency, 500 MHz, and the available room, 1260 mm, to install the accelerating cavities. Thanks to the 500 MHz frequency choice, some components of the new RF system for Elettra 2.0 are already installed and set into operation in the current Elettra storage ring. Their features and performance’s optimization can therefore start well in advance with respect to the foreseen operation the new Elettra 2.0 storage ring.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS061  
About • Received ※ 06 June 2022 — Accepted ※ 21 June 2022 — Issue date ※ 04 July 2022  
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TUPOMS062 Overall Performance of 26 Power Stations at 400 kW - 352 MHz ion-source, radio-frequency, controls, linac 1573
 
  • C. Pasotti, A. Cuttin
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
 
  The spoke cavities section of the European Spallation Source (ESS) Linac will be powered by 26 Radio Frequency Power Stations (RFPSs). Each RFPS delivers 400 kW of Radio Frequency (RF) power at 352.21 MHz in pulsed mode at a repetition rate up to 14 Hz and a 5 % duty cycle, thanks to a twin tetrodes RF power sources integration. This equipment belongs to the Italian In-Kind Contributions (IKCs) to ESS. Elettra Sincrotrone Trieste S.C.p.A (Elettra) is responsible for the development, manufacturing and commissioning of the RFPSs and is managing the RFPS manufacturing contract awarded to European Science Solutions s.r.l (ESS-It). So far, 24 units have been delivered and, by mid 2022, the entire contribution, plus a complete spare unit, will be delivered to ESS. The overall performance of the RFPSs, the lessons learned, and the optimizations adopted along the manufacturing process and the difficulties that the COVID-19 pandemic has posed along the way are presented in this contribution.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS062  
About • Received ※ 07 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 04 July 2022
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WEIXGD1 EIC Beam Dynamics Challenges electron, hadron, luminosity, polarization 1576
 
  • D. Xu, E.C. Aschenauer, G. Bassi, J. Beebe-Wang, J.S. Berg, W.F. Bergan, M. Blaskiewicz, J.M. Brennan, S.J. Brooks, K.A. Brown, Z.A. Conway, K.A. Drees, A.V. Fedotov, W. Fischer, C. Folz, D.M. Gassner, X. Gu, R.C. Gupta, Y. Hao, C. Hetzel, D. Holmes, H. Huang, J. Kewisch, Y. Li, C. Liu, H. Lovelace III, G.J. Mahler, D. Marx, F. Méot, M.G. Minty, C. Montag, S.K. Nayak, R.B. Palmer, B. Parker, S. Peggs, V. Ptitsyn, V.H. Ranjbar, G. Robert-Demolaize, M.P. Sangroula, S. Seletskiy, K.S. Smith, S. Tepikian, R. Than, P. Thieberger, N. Tsoupas, J.E. Tuozzolo, E. Wang, D. Weiss, F.J. Willeke, H. Witte, Q. Wu, W. Xu, A. Zaltsman
    BNL, Upton, New York, USA
  • S.V. Benson, B.R. Gamage, J.M. Grames, T.J. Michalski, E.A. Nissen, J.P. Preble, R.A. Rimmer, T. Satogata, A. Seryi, M. Wiseman, W. Wittmer
    JLab, Newport News, Virginia, USA
  • A. Blednykh, Y. Luo, B. Podobedov, S. Verdú-Andrés
    Brookhaven National Laboratory (BNL), Electron-Ion Collider, Upton, New York, USA
  • Y. Cai, Y.M. Nosochkov, G. Stupakov, M.K. Sullivan
    SLAC, Menlo Park, California, USA
  • E. Gianfelice-Wendt
    Fermilab, Batavia, Illinois, USA
  • G.H. Hoffstaetter, D. Sagan, J.E. Unger
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • V.S. Morozov
    ORNL RAD, Oak Ridge, Tennessee, USA
  • J. Qiang
    LBNL, Berkeley, California, USA
 
  The Electron Ion Collider aims to produce luminosities of 1034 cm-2s-1 . The machine will operate over a broad range of collision energies with highly polarized beams. The coexistence of highly radiative electrons and nonradiative ions produce a host of unique effects. Strong hadron cooling will be employed for the final factor of 3 luminosity boost.  
slides icon Slides WEIXGD1 [3.952 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEIXGD1  
About • Received ※ 06 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 14 June 2022
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WEOXGD3 An Alternative Design for BEPCII Upgrade lattice, survey, positron, emittance 1591
 
  • H. Geng, J. Xing, C.H. Yu, Y. Zhang
    IHEP, Beijing, People’s Republic of China
 
  The Beijing Electron Positron Collider II (BEPCII) has achieved a series of achievements in high energy physics study. Along with the deepening of the research, more important physics is expected in higher energy region (>2.1 GeV). As the upper limit of BEPCII design energy is 2.1 GeV, an urgent upgrade is required for BEPCII. To achieve a higher luminosity at higher energy, the number of RF cavities is expected to be doubled. The baseline design which kept the survey of the North Collision Region (NCR) unchanged for the upgrade of BEPCII has been studied in previous work. In this paper, we show an alternative design that modifies the survey of NCR, but enables the online maintenance of both RF cavities in each ring of BEPCII. The dynamic aperture tracking result shows that the lattice could meet the injection requirement of BEPCII beam with reasonable margin.  
slides icon Slides WEOXGD3 [3.761 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEOXGD3  
About • Received ※ 07 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 04 July 2022 — Issue date ※ 10 July 2022
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WEOXSP3 mm-Wave Structure Development for High Gradient Acceleration coupling, simulation, GUI, distributed 1606
 
  • E.J.C. Snively, A.E. Gabriel, E.A. Nanni, M.A.K. Othman, A.V. Sy
    SLAC, Menlo Park, California, USA
  • A.E. Gabriel
    UCSC, Santa Cruz, California, USA
 
  Funding: This work is supported by U.S. Department of Energy Contract No. DE-AC02-76SF00515, SLAC LDRD project 21-014 and Internal Agency Agreement 21-0007-IA (MIPR HR0011150657).
We report on the design of mm-wave accelerator structures operating near 100 GHz. Simulations of the cavity geometry and RF coupling are performed in ANSYS-HFSS and using SLAC’s parallel electromagnetic code suite ACE3P. We present experimental results for structures fabricated from copper, niobium, and copper plated with NbTiNi. We report on techniques for tuning these high frequency structures, as well as preliminary brazing results. A mm-wave accelerator cavity enables not only a high achievable gradient due to higher breakdown thresholds, but also reduced fill times which decrease pulsed heating and allow for higher repetition rates. We discuss the potential advantages and challenges for applications requiring ultra-compact structures.
 
slides icon Slides WEOXSP3 [1.800 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEOXSP3  
About • Received ※ 08 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 16 June 2022
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WEOYSP3 Operation Experience with SESAME RF System operation, injection, LLRF, controls 1636
 
  • D.S. Foudeh, A.I. Kurdi, N.Kh. Sawai
    SESAME, Allan, Jordan
 
  SESAME RF system has been in operation since 2017 where the operational electron beam current has been increased from 100mA to 300mA since then. The higher operational beam current together with the need to have longer beam lifetime to reduce number of injections per day required higher forward RF power, On the other hand; more attention needed to be paid to monitor and tackle the current driven High Order Modes and to respect the limitation on the forward RF power coming from the solid state amplifiers. In this paper we describe the RF system and report on the challenges we faced in addition to the operational experience we had with the RF system and solid state amplifiers.  
slides icon Slides WEOYSP3 [4.207 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEOYSP3  
About • Received ※ 03 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 07 July 2022
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WEPOST007 Centre-of-Mass Energy in FCC-ee collider, radiation, polarization, simulation 1683
 
  • J. Keintzel, R. Tomás García, F. Zimmermann
    CERN, Meyrin, Switzerland
  • A.P. Blondel
    DPNC, Genève, Switzerland
  • D.N. Shatilov
    BINP SB RAS, Novosibirsk, Russia
 
  The Future Circular electron-positron Collider (FCC-ee) is designed for high precision particle physics experiments. This demands a precise knowledge of the beam energies, obtained by resonant depolarization, and from which the center-of-mass energy and possible boosts at all interaction points are then determined. At the highest beam energy mode of 182.5 GeV, the energy loss due to synchrotron radiation is about 10 GeV per revolution. Hence, not only the location of the RF cavities, but also a precise control of the optics and understanding of beam dynamics, are crucial. In the studies presented here, different possible locations of the RF-cavities are considered, when calculating the beam energies over the machine circumference, including energy losses from crossing angles, a non-homogeneous dipole distribution, and an estimate of the beamstrahlung effect at the collision point.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST007  
About • Received ※ 08 June 2022 — Revised ※ 17 June 2022 — Accepted ※ 24 June 2022 — Issue date ※ 27 June 2022
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WEPOST025 A High Power Prototype of a Harmonic Kicker Cavity kicker, operation, MMI, electron 1749
 
  • G.-T. Park, G.A. Grose, J. Guo, A. OBrien, R.A. Rimmer, H. Wang, R.S. Williams
    JLab, Newport News, Virginia, USA
  • S.A. Overstreet
    ODU, Norfolk, Virginia, USA
 
  A harmonic kicker, a beam exchange device that can deflect the beam at an ultra-fast time scale (a few ns), has been developed in Jefferson Lab *, **. The high power prototype that can deliver more than a 100 kV kick at 7 kW was fabricated. The RF performance of cavity such as the harmonic resonant frequencies, kick profiles, it’s stability, and electric center is tested at bench. The cavity will eventually be tested with a beam at Upgraded Injector Test Facility (UITF) in Jefferson Lab. In this paper, we report some features of fabrication and bench test results. We also briefly describe our beam test plan in the future.
* G.Park, H.Wang, R.A.Rimmer, S. Wang, and J.Guo, THP092, Proceedings of IPAC2018, Vancouver, Canada (2018).
** G.Park, et al, WEPRBO99, Proceedings of IPAC2019, Melbourne, Australia (2019).
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST025  
About • Received ※ 11 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 20 June 2022
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WEPOPT023 A Design of ILC E-Driven Positron Source positron, electron, linac, acceleration 1889
 
  • M. Kuriki, S. Konno, Z.J. Liptak
    HU/AdSM, Higashi-Hiroshima, Japan
  • M.K. Fukuda, T. Omori, Y. Seimiya, J. Urakawa, K. Yokoya
    KEK, Ibaraki, Japan
  • S. Kashiwagi
    Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
  • H. Tajino
    HU ADSE, Hiroshima, Japan
  • T. Takahashi
    Hiroshima University, Graduate School of Science, Higashi-Hiroshima, Japan
 
  ILC is an electron-positron linear collider based on Superconducting linear accelerator. Linear collider is an only solution to realinze high energy electron-positron collision beyond the limit of synchrotron radiation energy loss by ring colliders. Beam current of injector of linear colliders is much larger than that of ring colliders because the beam is not reusable. Providing an enough amount of particles, especially positron is a technical issue. In this article, we present a design of electron driven positron source for ILC. After optimizations, the system design is established with an enough technical margin, e.g. avoiding potential damage on the production target.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT023  
About • Received ※ 20 May 2022 — Revised ※ 11 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 23 June 2022
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WEPOPT024 Beam Loading Compensation of Standing Wave Linac with Off-Crest Acceleration positron, beam-loading, acceleration, klystron 1893
 
  • M. Kuriki, S. Konno, Z.J. Liptak
    HU/AdSM, Higashi-Hiroshima, Japan
  • M.K. Fukuda, T. Omori, Y. Seimiya, J. Urakawa, K. Yokoya
    KEK, Ibaraki, Japan
  • S. Kashiwagi
    Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
  • H. Tajino
    HU ADSE, Hiroshima, Japan
  • T. Takahashi
    Hiroshima University, Graduate School of Science, Higashi-Hiroshima, Japan
 
  In E-Driven positron source of ILC, the generated positron is captured by a standing wave cavity. Because the deceleration capture method is employed, the positron is off-crest over the linac. Because the beam-loading is expected to be more than 1A in a multi-bunch format, the compensation is essential to obtain uniform intensity over the pulse. A conventional method for the compensation controlling the timing doesn’t work because RF and Beam induced field are in different phase. In this manuscript, we discuss the compensation with the off-crest acceleration case. A simple phase modulation on the input RF is a solution.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT024  
About • Received ※ 20 May 2022 — Revised ※ 10 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 16 June 2022
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WEPOPT032 Summary of the 3-year Beam Energy Scan II operation at RHIC luminosity, electron, operation, space-charge 1908
 
  • C. Liu, P. Adams, E.N. Beebe, S. Binello, I. Blackler, M. Blaskiewicz, K.A. Brown, D. Bruno, B.D. Coe, K.A. Drees, A.V. Fedotov, W. Fischer, C.J. Gardner, C.E. Giorgio, X. Gu, T. Hayes, K. Hock, H. Huang, R.L. Hulsart, T. Kanesue, D. Kayran, N.A. Kling, B. Lepore, Y. Luo, D. Maffei, G.J. Marr, A. Marusic, K. Mernick, R.J. Michnoff, M.G. Minty, J. Morris, C. Naylor, S. Nemesure, M. Okamura, I. Pinayev, S. Polizzo, D. Raparia, G. Robert-Demolaize, T. Roser, J. Sandberg, V. Schoefer, S. Seletskiy, F. Severino, T.C. Shrey, P. Thieberger, M. Valette, A. Zaltsman, I. Zane, K. Zeno, W. Zhang
    BNL, Upton, New York, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Beam Energy Scan phase II (BES-II) operation in the Relativistic Heavy Ion Collider (RHIC), aiming to explore the phase transition between quark-gluon plasma (QGP) and hadronic gas, exceeded the goal of a four-fold increase in the average luminosity over the range of five gold beam energies (9.8, 7.3, 5.75, 4.59 and 3.85 GeV/nucleon) compared to those achieved during Beam Energy Scan phase I (BES-I). We will present the achievements in BES-II together with a summary of the measures taken to improve RHIC performance in the presence of several beam dynamics effects, and details on improvements made during the operation at 3.85 GeV/nucleon in 2021.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT032  
About • Received ※ 06 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 17 June 2022
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WEPOPT035 Optics for Strong Hadron Cooling in EIC HSR-IR2 electron, hadron, optics, kicker 1920
 
  • S. Peggs, W.F. Bergan, D. Bruno, Y. Gao, D. Holmes, R.F. Lambiase, C. Liu, H. Lovelace III, G.J. Mahler, V. Ptitsyn, G. Robert-Demolaize, R. Than, J.E. Tuozzolo, E. Wang, D. Weiss, D. Xu
    BNL, Upton, New York, USA
  • S.V. Benson, T.J. Michalski
    JLab, Newport News, Virginia, USA
  • F. Micolon
    Brookhaven National Laboratory (BNL), Electron-Ion Collider, Upton, New York, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC001 2704, and by Jefferson Science Associates, LLC under Contract No. DE-AC05-06OR23177.
Insertion Region 2 (IR2) of the Relativistic Heavy Ion Collider will be modified to accommodate a Strong Hadron Cooling facility in the Hadron Storage Ring (HSR) of the Electron-Ion Collider (EIC). This paper describes the current proof-of-principle design of HSR-IR2 - layout, optical performance, design methodology, and engineering requirements. It also describes the challenges and opportunities in the future development of the HSR-IR2 design, in order to further optimize Strong Hadron Cooling performance.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT035  
About • Received ※ 02 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 18 June 2022 — Issue date ※ 06 July 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPOPT037 Dynamic Aperture Evaluation for EIC Hadron Storage Ring with Crab Cavities and IR Nonlinear Magnetic Field Errors dynamic-aperture, electron, proton, simulation 1927
 
  • Y. Luo, J.S. Berg, W. Fischer, X. Gu, H. Lovelace III, C. Montag, S. Peggs, V. Ptitsyn, H. Witte, D. Xu
    BNL, Upton, New York, USA
  • Y. Hao
    FRIB, East Lansing, Michigan, USA
  • V.S. Morozov
    ORNL RAD, Oak Ridge, Tennessee, USA
  • J. Qiang
    LBNL, Berkeley, California, USA
  • T. Satogata
    JLab, Newport News, Virginia, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 and Jefferson Science Associates, LLC under Contract No. DE-AC05-06OR23177.
The electron ion collider (EIC) presently under construction at Brookhaven National Laboratory will collider polarized high energy electron beams with hadron beams with luminosities up to 1034 cm-2s-1 in the center mass energy range of 20-140 GeV. In this article, we evaluate the dynamic aperture of the Hadron Storage Ring (HSR) with symplectic element-by-element tracking. Crab cavities, nonlinear magnetic field errors, and weak-strong beam-beam interaction are included. We compared the dynamic aperture from head-on collision to crossing-angle collision and found the reason for the dynamic aperture drop. We also studied the field error tolerances for IR magnets and for some particular magnets.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT037  
About • Received ※ 22 May 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 27 June 2022
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WEPOPT049 Beam-Beam Interaction for Tilted Storage Rings simulation, electron, collider, storage-ring 1968
 
  • D. Xu, D. Holmes, C. Montag, F.J. Willeke
    BNL, Upton, New York, USA
  • Y. Hao
    FRIB, East Lansing, Michigan, USA
  • Y. Luo
    Brookhaven National Laboratory (BNL), Electron-Ion Collider, Upton, New York, USA
  • J. Qiang
    LBNL, Berkeley, California, USA
 
  In the Electron-Ion Collider (EIC) design, to avoid vertical orbit bumps in the Electron Storage Ring (ESR) at some crossing points with Hadron Storage Ring (HSR) to preserve the electron polarization, we plan to tilt the ESR plane by 200 ’rad with an axis connecting IP6 and IP8. In this article, we study the beam-beam interaction when two rings are not in the same plane. The Lorentz boost formula is derived and the required vertical crabbing strength is calculated to compensate the dynamic effect The strong-strong simulations are performed to validate the theory.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT049  
About • Received ※ 16 May 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 06 July 2022
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WEPOPT050 Detector Solenoid Compensation in the EIC Electron Storage Ring solenoid, detector, simulation, collider 1972
 
  • D. Xu
    BNL, Upton, New York, USA
  • Y. Luo
    Brookhaven National Laboratory (BNL), Electron-Ion Collider, Upton, New York, USA
 
  The Electron Ion Collider (EIC) uses crab cavities to restore the geometrical luminosity loss. Due to the space limitation, the detector solenoid cannot be compensated locally. This paper presents the lattice design to compensate the detector solenoid without interfering the crab cavities. The skew quadrupoles are employed to avoid additional crab cavities. The correction scheme is checked by beam-beam simulation.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT050  
About • Received ※ 19 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 28 June 2022
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WEPOPT055 Linac3, LEIR and PS Performance with Ions in 2021 and Prospects for 2022 linac, operation, LLRF, injection 1983
 
  • N. Biancacci, S.C.P. Albright, R. Alemany-Fernández, D. Alves, M.E. Angoletta, D. Barrientos, H. Bartosik, G. Bellodi, S.B. Bertolo, D. Bodart, M. Bozzolan, H. Damerau, F.D.L. Di Lorenzo, A. Frassier, D. Gamba, A. Huschauer, S. Jensen, V. Kain, T. Koevener, G. Kotzian, D. Küchler, A. Lasheen, G. Le Godec, T.E. Levens, N. Madysa, E. Mahner, O. Marqversen, C.M. Mastrostefano, P.D. Meruga, C. Mutin, M. O’Neil, G. Piccinini, R. Scrivens, P.S. Solvang, D. Valuch, F.M. Velotti, R. Wegner, C. Wetton, M. Zampetakis
    CERN, Meyrin, Switzerland
 
  CERN accelerators underwent a period of long shutdown from the end of 2018 to 2020. During this time frame, significant hardware and software upgrades have been put in place to increase the performance of both proton and ion accelerator chains in the High Luminosity LHC era. In the context of the CERN lead ion chain, 2021 has been mainly devoted to restore the injectors’ performance and to successfully prove the slip-stacking technique in SPS. In this paper we summarise the key milestones of the ion beam commissioning and the achieved beam performance for the Linac 3 (including the source), LEIR and PS accelerators, together with an outlook on 2022 operation.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT055  
About • Received ※ 03 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 17 June 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPOTK004 Status and Upgrade Plan of the MR Ring RF Systems in J-PARC operation, power-supply, proton, experiment 2031
 
  • K. Hasegawa, K. Hara, C. Ohmori, Y. Sugiyama, M. Yoshii
    KEK, Ibaraki, Japan
  • M. Nomura, H. Okita, T. Shimada, F. Tamura, M. Yamamoto
    JAEA/J-PARC, Tokai-mura, Japan
 
  The J-PARC Main Ring (MR) is a high intensity proton accelerator and delivers 30 GeV proton beams for the long-base line neutrino experiment and the hadron experiments. At present, the beam intensity supplied to the neutrino experiment reached 520 kW with a cycle time of 2.48 s. Toward the design beam power of 750 kW and future goal of 1.3 MW, we chose shortening the MR operation cycle. Accelerating time is shortened in order to shorten the cycle, so a high accelerating voltage is required. Therefore, it is necessary to upgrade the RF systems. This RF upgrade expands the current nine RF systems to a total of thirteen. We are planning to fabricate four RF power sources and add four additional cavities that are recombined with existing cavities. The present status and upgrade plan of the MR RF systems are reported.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK004  
About • Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 23 June 2022 — Issue date ※ 07 July 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPOTK012 Commissioning the New LLRF System of the CERN PS Booster operation, injection, LLRF, MMI 2060
 
  • S.C.P. Albright, M.E. Angoletta, D. Barrientos, A. Findlay, M. Jaussi, J.C. Molendijk
    CERN, Meyrin, Switzerland
 
  The PS Booster (PSB) is the first synchrotron in the injection chain for protons. The beams produced for the LHC and various fixed target experiments cover a very large parameter space. Over the Long Shutdown 2 (LS2), the PSB was heavily upgraded as part of the LHC Injectors Upgrade (LIU) project. The low-level RF systems now drive the new Finemet-loaded cavities, control RF synchronisation for the new injection mechanism, and cope with the increased injection and extraction energies. The Finemet cavities provide exceptional flexibility, allowing an arbitrary distribution of voltage at different revolution frequency harmonics, but at the cost of significant broadband impedance. The new injection mechanism allows bunch-to-bucket multi-turn injection, which significantly reduces the amount of beam loss at the start of the cycle. The longitudinal beam production schema for each beam-type was developed based on simulations during LS2, and then adapted during the setting-up phase to suit the final operational configuration. This paper discusses the commissioning of the new LLRF, and the consequences of the LIU upgrades on the production of various beams.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK012  
About • Received ※ 25 May 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 07 July 2022
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WEPOTK013 Direct Impedance Measurement of the CERN PS Booster Finemet Cavities impedance, booster, simulation, proton 2064
 
  • S.C.P. Albright, M.E. Angoletta, D. Barrientos, A. Findlay, M. Jaussi, J.C. Molendijk
    CERN, Meyrin, Switzerland
 
  Over CERN’s Long Shutdown 2, the conventional ferrite-loaded cavities of the PS Booster were replaced with wide-band Finemet-loaded cavities. The Finemet cavities bring many operational advantages, but also represent a significant broadband impedance source. The impedance is mitigated by servo loops, which suppress the induced voltage, reducing the impedance as seen by the beam. Accurately including the impedance of the cavity and the effect of the servoloops in longitudinal tracking simulations is essential to predict the performance with beam. This paper discusses the results of a measurement campaign, which is intended to give a direct measurement of the cavity impedance. Using the detected voltage and the measured beam profile, the cavity impedance can be inferred and used to improve beam dynamics modelling.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK013  
About • Received ※ 26 May 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 03 July 2022
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WEPOTK015 The Electron-Ion Collider Hadron Storage Ring 10 O’clock Switchyard Design dipole, hadron, quadrupole, electron 2071
 
  • H. Lovelace III, J.S. Berg, D. Bruno, C. Cullen, K.A. Drees, W. Fischer, X. Gu, R.C. Gupta, D. Holmes, R.F. Lambiase, C. Liu, C. Montag, S. Peggs, V. Ptitsyn, G. Robert-Demolaize, R. Than, J.E. Tuozzolo, M. Valette, D. Weiss
    BNL, Upton, New York, USA
  • B. Bhandari, F. Micolon, S. Verdú-Andrés
    Brookhaven National Laboratory (BNL), Electron-Ion Collider, Upton, New York, USA
  • T. Satogata, W. Wittmer
    JLab, Newport News, Virginia, USA
 
  The Electron-Ion Collider (EIC) Hadron Storage Ring (HSR) will be composed of the current Relativistic Heavy Ion Collider (RHIC) yellow ring sextants with the exception of the 1 o’clock and the 11 o’clock arc. These two arcs use the existing blue ring inner (1 o’clock) and outer (11 o’clock) magnetic lattice for 275 GeV proton operation. The inner yellow 11 o’clock arc is used for 41 GeV energy operation. A switching magnet must be used to guide the hadron beam from the low and high energy arc respectively into the shared arc. This report provides the necessary lattice configuration, magnetic fields, and optics for the 10 o’clock utility straight section (USS) switchyard for both high and low energy configuration while providing the necessary space allocations and beam specifications for accelerator systems such as an additional radiofrequency cavity and beam dump.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK015  
About • Received ※ 01 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 26 June 2022
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WEPOTK028 Implementation of RF Channeling at the CERN PS for Spill Quality Improvements flattop, extraction, resonance, simulation 2114
 
  • P.A. Arrutia Sota, H. Damerau, M.A. Fraser, M. Vadai, F.M. Velotti
    CERN, Meyrin, Switzerland
  • P. Burrows
    JAI, Oxford, United Kingdom
 
  Resonant slow extraction from synchrotrons aims at providing constant intensity spills over timescales much longer than the revolution period of the machine. However, the extracted intensity is undesirably modulated by noise on the machine’s power converters with a frequency range of between 50 Hz and a few kHz. The impact of power converter noise can be suppressed by exploiting a Radio Frequency (RF) technique known as empty bucket channelling, which increases the speed at which particles cross the tune resonance boundary. In this contribution the implementation of empty bucket channelling in the CERN Proton Synchrotron (PS) is described via simulation and measurement. The technique was tested with both a resonant RF cavity and an inductive Finemet cavity, which can produce non-sinusoidal waveforms, to significantly reduce the low frequency noise observed on the extracted spill.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK028  
About • Received ※ 07 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 22 June 2022
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WEPOTK046 Improved Longitudinal Performance of the LHC Beam in the CERN PS feedback, extraction, emittance, flattop 2165
 
  • H. Damerau, V.D. Desquiens, A. Huschauer, A. Jibar, A. Lasheen, B. Mikulec, M. Morvillo, C. Rossi, B.J. Woolley
    CERN, Meyrin, Switzerland
 
  At the end of the 2018 run the intensity target for the High-Luminosity LHC (HL-LHC) had just been reached at extraction from the Proton Synchrotron (PS). In the framework of the LHC Injectors Upgrade (LIU) project additional RF improvements have been implemented during the 2019/2020 long shutdown (LS2), mainly impacting the impedance of the 10 MHz, 40 MHz, and 80 MHz RF systems. With the upgraded injection energy of 2 GeV (kinetic), also the intermediate plateau energy for RF manipulations has been increased. Following a campaign of beam studies throughout the 2021 run, a bunch intensity of up to 2.9·1011 p/b in trains of 72 bunches is achieved with the required longitudinal beam quality, surpassing the LIU target of 2.6·1011 p/b. The threshold of longitudinal quadrupolar coupled-bunch instabilities is increased during acceleration, but they are again observed at the flat-top. While dipolar coupled-bunch oscillations are well damped by a dedicated feedback system, the quadrupolar modes are suppressed by operating a 40 MHz system as an active higher-harmonic Landau cavity. The main commissioning steps are outlined, together with the key contributions to the improved beam performance.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK046  
About • Received ※ 07 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 16 June 2022  
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WEPOTK059 Suppression of Emittance Growth by a Collective Force: Van Kampen Approach emittance, damping, feedback, impedance 2197
 
  • X. Buffat
    CERN, Meyrin, Switzerland
 
  In hadron synchrotrons, external sources of noise affecting the beam induce emittance growth through the mechanism of decoherence. Active feedbacks are often used to suppress this emittance growth. In the presence of beam-beam interactions, it was shown that coherent modes of oscillations with frequencies shifted outside of the incoherent spectrum significantly enhances the efficiency of the emittance growth suppression by active feedbacks. We show that the same enhancement of the emittance growth suppression may be driven by a beam coupling impedance generating a real tune shift larger than the detuning.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK059  
About • Received ※ 03 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 15 June 2022  
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WEPOTK060 Prospects of Ultrafast Electron Diffraction Experiments at Sealab electron, experiment, SRF, gun 2201
 
  • B. Alberdi-Esuain, J.-G. Hwang, T. Kamps, A. Neumann, J. Völker
    HZB, Berlin, Germany
  • T. Kamps
    HU Berlin, Berlin, Germany
 
  Ultrafast Electron Diffraction (UED) is a pump-probe experimental technique that aims to image the structural changes that happen in a target structure due to photo-excitation. Development of MeV UED capabilities is one of the main objectives at Sealab, a superconducting RF accelerator facility being commissioned in Helmholtz-Zentrum Berlin. In order to perform UED experiments, the optimization of temporal resolution is of the utmost importance. The composition of the SRF Photoinjector, currently the main beam-line in Sealab, offers superb flexibility to manipulate the longitudinal phase-space of the electron bunch. At the same time, the CW operation of the accelerator provides an enhanced beam stability compared to warm guns, together with MHz repetition rates. This work aims to show the capacity of the SRF Photoinjector in Sealab to reach the required temporal resolution and explain the development and current status of the necessary tools to perform UED experiments at the facility.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK060  
About • Received ※ 08 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 03 July 2022  
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WEPOMS003 Beam Dynamics with a Superconducting Harmonic Cavity for the SOLEIL Upgrade simulation, synchrotron, SRF, operation 2229
 
  • A. Gamelin, W. Foosang, P. Marchand, R. Nagaoka
    SOLEIL, Gif-sur-Yvette, France
  • N. Yamamoto
    KEK, Ibaraki, Japan
 
  In 4th generation low emittance synchrotron light sources, harmonic cavities are critical components needed to reach the required performance. However, RF systems with harmonic cavities can be limited by their own set of instabilities. An instability dominated by the coupled-bunch mode l=1 can prevent the RF system from reaching the flat potential condition, hence limiting the maximum bunch lengthening. Here we report how this instability impacts the performance of 3rd and 4th harmonic superconducting cavities for the SOLEIL Upgrade.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS003  
About • Received ※ 08 June 2022 — Accepted ※ 22 June 2022 — Issue date ※ 26 June 2022  
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WEPOMS008 Impact of Broadband Impedance on Longitudinal Coupled-Bunch Instability Threshold impedance, HOM, synchrotron, damping 2245
 
  • I. Karpov, E.N. Shaposhnikova
    CERN, Meyrin, Switzerland
 
  Coupled-bunch instabilities (CBI) and the loss of Landau damping (LLD) in the longitudinal plane can affect the performance of high-current synchrotrons. The former is driven by the narrowband impedance of resonant structures, while the latter is mainly determined by the broadband impedance of the entire accelerator and is a single-bunch effect. Therefore, the CBI and LLD thresholds are usually evaluated separately in order to define the corresponding critical impedance budget for given beam parameters. In this paper, we show that the CBI threshold in the presence of broadband impedance can be significantly lower than the one defined by only the narrowband impedance, especially if the LLD threshold is below the CBI threshold. In some cases, the beam becomes unstable even below the LLD threshold. This explains the low CBI threshold observed for the LHC-type beams in the CERN SPS. For HL-LHC, the broadband impedance may also significantly reduce the CBI threshold driven by higher-order modes of the crab cavities.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS008  
About • Received ※ 08 June 2022 — Accepted ※ 04 July 2022 — Issue date ※ 06 July 2022  
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WEPOMS010 Studies of Transverse Coupled-Bunch Instabilities from Resistive-Wall and Cavity Higher Order Modes for Diamond-II impedance, simulation, HOM, storage-ring 2253
 
  • S.W. Wang, H.C. Chao, R.T. Fielder, I.P.S. Martin, T. Olsson
    DLS, Oxfordshire, United Kingdom
 
  The transverse coupled-bunch instabilities from resistive-wall impedance and main cavity higher order modes (HOMs) are studied for the Diamond-II storage ring. The growth rates of all the coupled-bunch modes are calculated using both the results from tracking simulations and analytic formula, which show a good consistency. The instability threshold from the resistive-wall impedance is estimated and verified by simulation. The impact of the main cavity HOMs is studied in a similar way, and the results show instabilities from HOMs are much smaller than that from resistive-wall impedance.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS010  
About • Received ※ 06 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 05 July 2022  
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WEPOMS011 Single Bunch Instability Studies with a New Impedance Database for Diamond-II impedance, database, lattice, synchrotron 2257
 
  • R.T. Fielder, H.C. Chao, S.W. Wang
    DLS, Oxfordshire, United Kingdom
 
  We present an updated impedance database for the Diamond-II storage ring, along with an analysis of single bunch instabilities and thresholds based on particle tracking simulations using Elegant. Various cases with different chromaticity, insertion device parameters and harmonic cavity settings are studied, and the effects on the microwave instability, bunch lengthening and phase shifts are simulated and compared with analytic formulae. Preliminary results show that the single-bunch instability thresholds are above requirements for a uniform fill, and with inclusion of a harmonic cavity the longitudinal and transverse instability thresholds can also satisfy requirements for a hybrid fill.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS011  
About • Received ※ 07 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 22 June 2022
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WEPOMS025 Injector Design Towards ERL-Based EUV-FEL for Lithography emittance, electron, FEL, solenoid 2299
 
  • O.A. Tanaka, T. Miyajima, N. Nakamura, T. Tanikawa
    KEK, Ibaraki, Japan
 
  A high-power EUV light source using ERL-based FEL can supply multiple semiconductor exposure de-vices. There are some requirements in the whole and its injector, in particular, and their examination and necessary development are being carried out. The requirement for the injector was to generate high bunch charge beams at a high-repetition rate. In this regard, a space charge effect should be treated carefully in the design of the injector. For FEL operation, not only short bunch length and small transverse emittance but also small longitudinal emittance are required. By using a multi-objective genetic algorithm, we are minimizing them at the exit of the injector to investigate the injector performance and its effect on the FEL generation. In this study, we describe the injector optimization strategies and possible options suited for the ERL-based EUV-FEL.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS025  
About • Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 17 June 2022
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WEPOMS033 CETA-A Code Package Being Developed for Collective Effect Analysis and Simulation in Electron Storage Rings simulation, impedance, storage-ring, collective-effects 2323
 
  • C. Li, Y.-C. Chae
    DESY, Hamburg, Germany
 
  The code Collective Effect Tool Analysis (CETA) is under development to study the collective effects in the electron storage ring. With the impedance either generated by itself or imported from an external file, CETA can calculate the loss and kick factors, the longitudinal equilibrium bunch length from a Haissinski solver, and the head-tail mode frequency shift from a Vlasov solver. Meanwhile, the code CETASim, which can track particles to study coupled-bunch instabilities caused by long-range wakefield, ion effects, transient beam loading effect, bunch-by-bunch feedback, etc., is also under development. In this paper, we describe the code status and give several simulation results from CETA and CETASim to show how these codes work.
This project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No. 871072
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS033  
About • Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 05 July 2022
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WEPOMS042 The HOMEN Model: An Estimator of High Order Modes Evolution in an Energy Recovery Linac HOM, electron, acceleration, linac 2342
 
  • S. Samsam, A. Bacci, V. Petrillo, M. Rossetti Conti, A.R. Rossi, M. Ruijter, L. Serafini
    INFN-Milano, Milano, Italy
  • A. Bosotti, R. Paparella, D. Sertore
    INFN/LASA, Segrate (MI), Italy
  • M.R. Masullo, A. Passarelli
    INFN-Napoli, Napoli, Italy
  • M. Opromolla
    Università degli Studi di Milano, Milano, Italy
 
  Energy recovery linacs represent the new frontier of energy sustainability in the field of particle accelerators while providing remarkable performance in terms of high average current and average brightness. Operating superconducting radio-frequency cavities in continuous wave makes high repetition rates (GHz-class) affordable and allows the construction of light sources such as FEL or Compton based characterized by high flux. \ This study originates in the context of the design study of BriXSinO, an ERL based on the two-pass two-way scheme à la Maury Tigner in which the cavities are traveled by the beam in both directions, the first time in the accelerating phase and the second time in the decelerating phase. HOMEN was conceived as a model to simulate the evolution of high order modes on long time scales in high Q cavities of machines of this kind and monitor their effects on the beam.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS042  
About • Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 21 June 2022
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WEPOMS049 ESS RFQ Electromagnetic Simulations Using CST Studio Suite rfq, simulation, radio-frequency-quadrupole, radio-frequency 2365
 
  • E. Trachanas, A. Bignami, N. Gazis, B. Jones, R. Zeng
    ESS, Lund, Sweden
  • G. Fikioris, E.N. Gazis, A. Kladas
    National Technical University of Athens, Zografou, Greece
  • P. Hamel, O. Piquet
    CEA-IRFU, Gif-sur-Yvette, France
 
  The Radio Frequency Quadrupole (RFQ) of the European Spallation Source (ESS), operates at 352.21 MHz with an RF pulse length of 3.2 ms and repetition rate of 14 Hz. The RFQ focuses, bunches and accelerates the 62.5 mA proton beam from 75 keV up to 3.6 MeV. In an effort to study and compare the results from 3D electromagnetic codes, different models of the RFQ were simulated with CST Studio suite. This paper presents the selection of optimal parameters for simulation of the RFQ cavity voltage and comparison of the results with the RFQ design code Toutatis.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS049  
About • Received ※ 08 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 17 June 2022
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THIXSP1 A New Compact 3 GeV Light Source in Japan vacuum, electron, emittance, quadrupole 2402
 
  • N. Nishimori
    QST, Tokai, Japan
 
  A new 3 GeV light source with a circumference of 350 m and an MBA lattice has been officially funded and is being constructed in north-eastern Japan. Aiming at stable and high-performance operations with an emittance of about 1 nm rad, various design and R&D activities are being performed: the four bend achromatic lattice using BQ combined function magnets; the compact RF system using a TM020 mode and in-cavity compact HOM absorbers; the in-vacuum off-axis injection scheme enabling stored beam oscillation-free injections with a small injection beam amplitude; the injector linac composed of a thermionic E-gun and C-band accelerators with a capability of extension to feed a future SX-FEL driver, and so on. The installation of accelerator components is ongoing. The talk will include the overall design of the light source, R&D results, and the latest construction status.  
slides icon Slides THIXSP1 [15.084 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THIXSP1  
About • Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 25 June 2022
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THOXSP2 Brixsino High-Flux Dual X-Ray and THz Radiation Source Based on Energy Recovery Linacs electron, laser, radiation, linac 2407
 
  • I. Drebot, F. Canella, S. Cialdi, M. Giammarchi, D. Giannotti, S. Latorre, C. Meroni, M. Rossetti Conti, A.R. Rossi, M. Ruijter, S. Samsam, L. Serafini, V. Torri
    INFN-Milano, Milano, Italy
  • M.P. Abbracchio, S. Altilia, B. Paroli, A. Vanzulli
    Universita’ degli Studi di Milano, Milano, Italy
  • A. Andreone, G.P. Papari
    Naples University Federico II, Napoli, Italy
  • A. Bacci, M. Bertucci, A. Bosotti, F. Broggi, D. Giove, P. Michelato, L. Monaco, R. Paparella, L. Rossi, D. Sertore, M. Statera
    INFN/LASA, Segrate (MI), Italy
  • R. Calandrino, A. Delvecchio
    HSP, Milan, Italy
  • S. Capra, D. Cipriani, C. Lenardi, M. Opromolla, E. Suerra, A. Torresin
    Università degli Studi di Milano, Milano, Italy
  • P. Cardarelli, G. Paternò, A. Taibi
    INFN-Ferrara, Ferrara, Italy
  • M. Citterio
    Universita’ degli Studi di Milano e INFN, Milano, Italy
  • A. Esposito
    LNF-INFN, Frascati, Italy
  • R. Ferragut, G. Galzerano
    POLIMI, Milano, Italy
  • C. Koral, M.R. Masullo, A. Passarelli
    INFN-Napoli, Napoli, Italy
  • Z. Mazaheri, G. Mettivier, P. Russo
    UniNa, Napoli, Italy
  • C. Pagani
    Università degli Studi di Milano & INFN, Segrate, Italy
  • P. Paparo
    CNR-ISASI, Pozzuoi, Italy
  • V. Petrillo, F. Prelz, M. Sorbi
    Universita’ degli Studi di Milano & INFN, Milano, Italy
  • B. Piccirillo, A. Rubano
    Naples University Federico II and INFN, Napoli, Italy
  • E. Puppin
    Politecnico/Milano, Milano, Italy
 
  We present the conceptual design of a compact light source named BriXSinO. BriXSinO was born as demonstrator of the Marix project, but it is also a dual high flux radiation source Inverse Compton Source (ICS) of X-ray and Free-Electron Laser of THz spectral range radiation conceived for medical applications and general applied research. The accelerator is a push-pull CW-SC Energy Recovery Linac (ERL) based on superconducting cavities technology and allows to sustain MW-class beam power with almost just one hundred kW active power dissipation/consumption. ICS line produces 33 keV monochromatic X-Rays via Compton scattering of the electron beam with a laser system in Fabry-Pérot cavity at a repetition rate of 100 MHz. The THz FEL oscillator is based on an undulator imbedded in optical cavity and generates THz wavelengths from 15 to 50 micron.  
slides icon Slides THOXSP2 [19.118 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THOXSP2  
About • Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 16 June 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
THPOST007 Slow-Control Loop to Stabilize the RF Power of the FLUTE Electron Gun controls, electron, gun, LLRF 2449
 
  • M.-D. Noll, A. Böhm, J. Jelonek, I. Križnar, O. Manzhura, A.-S. Müller, R. Ruprecht, M. Schuh, N.J. Smale
    KIT, Karlsruhe, Germany
 
  The linear accelerator FLUTE (Far Infrared Linac and Test Experiment) at KIT serves as a test facility for accelerator research and for the generation of ultra-intense coherent THz radiation. To achieve stable THz photon energy and optimal beam trajectory, the energy of the electrons emitted from the RF photo-injector must be stable. The accelerating voltage of the RF cavity has been shown to be a significant influencing factor. Here, we report on the development of a slow closed-loop feedback system to stabilize the RF power and thus the accelerating voltage in the RF photo-injector cavity. With this closed-loop feedback system the relative standard deviation of the RF power in the cavity can be improved by 8.5 %.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST007  
About • Received ※ 08 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 24 June 2022
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THPOST020 Visualisation of Pareto Optimal Spaces and Optimisation Solution Selection Using Parallel Coordinate Plots impedance, GUI, ECR, RF-structure 2487
 
  • S.J. Smith, R. Apsimon, G. Burt, M.J.W. Southerby
    Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
  • S. Setiniyaz
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • S. Setiniyaz
    Lancaster University, Lancaster, United Kingdom
 
  In this paper, we build on previous work where multi-objective genetic algorithms were used to optimise RF cavities using non-uniform rational basis splines (NURBS) to improve the cavity geometries and reduce peak fields. These optimisations can produce thousands of Pareto optimal solutions, from which a final cavity solution must be selected based on design criteria, such as accelerating gradient and power requirements. As all points are considered equally optimal, this can prove difficult without further analysis. Here we focus on the visualisation of the Pareto optimal points and the final solution selection process. We have found that the use of clustering algorithms and parallel coordinate plots (PCPs) provide the best way to represent the data and perform the necessary trade-offs between the peak fields and shunt impedance required to pick a final design.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST020  
About • Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 29 June 2022
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THPOST025 Operational Experience with the Improved VSR DEMO Collimating Shielded Bellow in BESSY II operation, SRF, vacuum, synchrotron 2497
 
  • H.-W. Glock, V. Dürr, F. Glöckner, J. Knobloch, M. Ries, A. Vélez
    HZB, Berlin, Germany
  • J. Knobloch
    University of Siegen, Siegen, Germany
  • A. Vélez
    Technical University Dortmund, Dortmund, Germany
 
  Funding: Work supported by grants of the Helmholtz Association
The Collimating Shielded Bellow (CsB) is designed to serve both as a flexible beam pipe connection between two adjacent superconducting cavities as foreseen in VSR DEMO and as a synchrotron light collimator to shield the down-stream cavity from synchrotron radiation. A convoluted inner RF shield was applied to prevent fundamental mode heating of the stainless-steel-made bellow in the cryogenic environment, making the such captured inner volume very difficult to access for inspection and cleaning. A first version of the device was successfully tested as part of the beam pipe of the synchrotron light source BESSY II under regular operation for more than a year. It suffered from an unfavorable long outgassing commissioning. Therefore a detachable design, allowing for rigorous inner surface preparation and cleaning, was built and recently installed in BESSY II. CsB version 2 design and experimental outcomes are described in the paper. First results indicated a significantly improved vacuum commissioning performance, which was confirmed later on.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST025  
About • Received ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 10 July 2022  
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THPOST026 Design of the Magnetic Shield for VSR DEMO simulation, shielding, SRF, GUI 2501
 
  • H.-W. Glock, P. Anumula, F. Glöckner, J. Knobloch, F. Pflocksch, A. Vélez
    HZB, Berlin, Germany
  • J. Knobloch
    University of Siegen, Siegen, Germany
  • A. Vélez
    Technical University Dortmund, Dortmund, Germany
 
  Funding: Work supported by grants of the Helmholtz Association
The VSR DEMO module, recently under development at HZB, will house two 4-cell 1.5 GHz superconducting RF cavities with a particularly powerful HOM damping scheme based on five waveguide HOM absorbers per cavity. A magnetic shield made of high-permeable material is needed around the cavities in order to prevent the ambient magnetic field exceeding very few µT thereby causing considerable unwanted RF losses. The shield needs to accommodate the waveguides, the fundamental power coupler, two beam pipes, two He feed / return lines, the tuner and the support structures, whilst being manufacturable and mountable. The paper discusses those difficulties and presents the matured magnetic shield design. Numerical simulations are used to evaluate the efficacy of the shield.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST026  
About • Received ※ 14 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 22 June 2022 — Issue date ※ 22 June 2022
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THPOST038 On-Site Transport and Handling Tests of Cryomodules for the European Spallation Source cryomodule, site, diagnostics, SRF 2527
 
  • F. Schlander, A. Bignami, N. Gazis
    ESS, Lund, Sweden
 
  The cryomodules for the superconducting Linac of the European Spallation Source ’ ESS are now arriving in a steady stream and the long-distance transport requirements are well understood. For the on-site transportation, handling and storage, several challenges have risen, including the intermediate storage of cryomodules before testing and/or installation. In comparison to the long-distance transports, the cryomodule on-site transports and respective handling until installation take place with specialised and limited transport protection. This requires additional measures and tests of those handling steps with extended diagnostics, to make sure that handling and transport refrains from damages on the last mile. Those handling procedures and executed tests will be described in this contribution.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST038  
About • Received ※ 07 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 25 June 2022
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THPOST040 Commissioning of an X-Band Cavity for Longitudinal Phase Space Linearization at UCLA PEGASUS Laboratory gun, electron, linac, emittance 2533
 
  • P.E. Denham, P. Musumeci, A. Ody
    UCLA, Los Angeles, USA
 
  This paper discusses the commissioning of an X-band (9.6 Ghz) linearizer cavity at the UCLA PEGASUS beamline. The photoinjector gun and booster linac operate at S-band (2.856 GHz) and the linearizer cavity can be used to compensate temporally correlated energy spread inherited by the use of relatively long (many ps) laser pulses at the photocathode. The cavity is comprised of 7 cells for a total length of a 9.45 cm, and is installed in the drift section between the gun and the linac. It can be used to remove higher order correlations and minimize the beam energy spread of 13 ps long beams to 10-4.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST040  
About • Received ※ 08 June 2022 — Revised ※ 21 June 2022 — Accepted ※ 22 June 2022 — Issue date ※ 27 June 2022
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THPOST045 Temperature Dependent Effects on RF Surface Resistivity cryogenics, electron, experiment, operation 2540
 
  • G.E. Lawler, A. Fukasawa, N. Majernik, J.B. Rosenzweig
    UCLA, Los Angeles, California, USA
 
  Funding: This work was supported by DOE Contract DE-SC0020409
A promising future for linear accelerators such as compact free electron lasers and electron positron colliders is higher gradient RF cavities enabled by cryogenic temperature operation. Breakdown rates have been shown empirically to be significantly reduced at low temperatures allowing for higher gradient. The surface physics associated with this observation is complicated and there many remain questions as to the exact phenomena responsible. One major figure of merit that can better inform the theory of breakdown is the RF surface resistivity which can be used to compute for example the RF pulse heating during operation. We then use techniques developed for previous Xband and Sband low power surface resistivity measurement by way of temperature dependent quality factor measurements to study Cband cavities. We first present a review of low temperature effects that may be responsible for the change in surface resistivity at low temperature. We then explain some of the initial measurements of these low power RF quality factor tests and compare them to a review some of the physical phenomena that could determine the low temperature surface effects.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST045  
About • Received ※ 08 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 20 June 2022
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THPOST046 CrYogenic Brightness-Optimized Radiofrequency Gun (CYBORG) cryogenics, cathode, gun, brightness 2544
 
  • G.E. Lawler, A. Fukasawa, N. Majernik, J.R. Parsons, J.B. Rosenzweig, Y. Sakai, A. Suraj
    UCLA, Los Angeles, California, USA
 
  Funding: This work was supported by the Center for Bright Beams, National Science Foundation Grant No. PHY-1549132 and DOE Contract DE-SC0020409
Producing higher brightness beams at the cathode is one of the main focuses for future electron beam applications. For photocathodes operating close to their emission threshold, the cathode lattice temperature begins to dominate the minimum achievable intrinsic emittance. At UCLA, we are designing a radiofrequency (RF) test bed for measuring the temperature dependence of the mean transverse energy (MTE) and quantum efficiency for a number of candidate cathode materials. We intend to quantify the attainable brightness improvements at the cathode from cryogenic operation and establish a proof-of-principle cryogenic RF gun for future studies of a 1.6-cell cryogenic photoinjector for the UCLA ultra compact XFEL concept (UC-XFEL). The test bed will use a C-band 0.5-cell RF gun designed to operate down to 45 K, producing an on-axis accelerating field of 120 MV/m. The cryogenic system uses conduction cooling and a load-lock system is being designed for transport and storage of air-sensitive high brightness cathodes.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST046  
About • Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 01 July 2022
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THPOPT005 Field Enhanced, Compact S-Band Gun Employing a Pin Cathode electron, gun, cathode, multipactoring 2567
 
  • R. Bazrafshan, T. Rohwer
    Deutsches Elektronen Synchrotron (DESY) and Center for Free Electron Science (CFEL), Hamburg, Germany
  • M. Fakhari, K. Flöttmann, F.X. Kaernter
    DESY, Hamburg, Germany
  • N.H. Matlis
    CFEL, Hamburg, Germany
 
  S-band RF-guns are highly developed for production of low emittance relativistic electron bunches, but need powerful klystrons for driving. Here, we present the design and first experimental tests of a compact S-band gun, which can accelerate electrons up to 180 keV powered by only 10 kW from a compact rack-mountable solid-state amplifier. A pin-cathode is used to enhance the RF electric field on the cathode up to 100 MV/m as in large-scale S-band guns. An electron bunch is generated through photoemission off a flat copper surface on the pin excited by a UV laser pulse followed by a focusing solenoid producing a low emittance bunch with 0.1 mm mrad transverse emittance for up to 100 fC bunch charge. We are currently in the conditioning phase of the gun and first experiments show good agreement with simulations. The compact gun will serve three purposes: (i) it can be used directly for ultrafast electron diffraction; (ii) as an injector into a THz booster producing 0.3MeV to 2 MeV electron bunches for ultrafast electron diffraction; (iii) The system in (ii) serves as an injector into a THz linear accelerator producing a 20 MeV beam for the AXSIS X-ray source project.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT005  
About • Received ※ 21 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 10 July 2022
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THPOPT017 Orbit Stability Studies for the Diamond-II Storage Ring electron, power-supply, storage-ring, resonance 2602
 
  • I.P.S. Martin, C.A. Abraham, D. Crivelli, H. Ghasem, B. Nicholson, T. Olsson, P. Sanchez Navarro
    DLS, Oxfordshire, United Kingdom
 
  The photon-beam positional stability relative to the beam size is a key performance parameter for storage ring light sources. The natural emittance of the Diamond-II ring will be lowered by a factor 16.7 compared to the existing ring, so the absolute stability requirement for the electron beam must reduce accordingly. In addition, advances in detector speed and resolution mean the tolerances are tighter compared to previous generations of storage rings, with a target of 3 % of beam size up to 1 kHz having been adopted for Diamond-II. In this paper we present studies of how the anticipated ground vibrations, girder motion and power supply ripple will affect the electron beam stability as a function of frequency.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT017  
About • Received ※ 08 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 06 July 2022  
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THPOPT035 A Second Generation Light Source Aiming at High Power on the Giant Dipole Resonance insertion, dipole, photon, resonance 2661
 
  • X. Buffat, L.L. Cuanillon, E.N. Kneubuehler
    CERN, Meyrin, Switzerland
 
  We propose an accelerator concept which could enable nuclear waste transmutation and energy amplification using a second generation light source rather than a high power proton beam. The main parameters of the ring and insertion devices are estimated, targeting a photon beam power of 1 GW with a spectrum that maximizes the potential for nuclear reactions via the Giant Dipole Resonance. The synergies with technologies developed for high energy physics, in particular within the Future Circular Collider study (FCC), are highlighted.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT035  
About • Received ※ 03 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 25 June 2022
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THPOPT037 Ceramics Evaluation for MW-Power Coaxial Windows, Operating in UHF Frequency Range Windows, vacuum, electron, multipactoring 2668
 
  • S.V. Kutsaev, R.B. Agustsson, P.R. Carriere, N.G. Matavalam, A.Yu. Smirnov, S.U. Thielk
    RadiaBeam, Santa Monica, California, USA
  • A.A. Haase
    SLAC, Menlo Park, California, USA
  • T.W. Hall, D. Kim, J.T.M. Lyles, K.E. Nichols
    LANL, Los Alamos, New Mexico, USA
 
  Funding: This work was supported by the U.S. Department of Energy, Office of Basic Energy Science, under SBIR grant DE- SC0021552
Modern accelerator facilities require reliable high-power RF components. The RF vacuum window is a critical part of the waveguide couplers to the accelerating cavities. It is the point where the RF feed crosses the vacuum boundary and thus forms part of the confinement barrier. RF windows must be designed to have low power dissipation inside their ceramic, be resistant to mechanical stresses, and free of discharges. In this paper, we report on the evaluation of three different ceramic candidates for high power RF windows. These materials have low loss tangents, low secondary electron yield (SEY), and large thermal expansion coefficients. The acquired materials were inspected, coated, and measured to select the optimal set.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT037  
About • Received ※ 01 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 04 July 2022
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THPOPT053 Goubau-Line Set Up for Bench Testing Impedance of IVU32 Components impedance, simulation, undulator, vacuum 2719
 
  • P.I. Volz, A. Meseck
    HZB, Berlin, Germany
  • A. Meseck
    KPH, Mainz, Germany
 
  The worldwide first in-vacuum elliptical undulator, IVUE32, is being developed at Helmholtz-Zentrum Berlin. The 2.5 m long device with a period length of 3.2 cm and a minimum gap of about 7 mm is to be installed in the BESSY II storage ring. It will deliver radiation in the soft X-ray range to several beamlines. The proximity of the undulator structure to the electron beam makes the device susceptible to wakefield effects which can influence beam stability. A complete understanding of its impedance characteristics is required prior to installation and operation, as unforeseen heating of components could have catastrophic consequences. To understand and measure the IVU’s impedance characteristics a Goubau-Line test stand is being designed. A Goubau-line is a single wire transmission line for high frequency surface waves with a transverse electric field resembling that of a charged particle beam out to a certain radial distance. A concept optimized for bench testing IVUE32-components will be discussed, microwave simulations will be presented together with first measurements from a test stand prototype.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT053  
About • Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 16 June 2022
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THPOTK025 Heat Loads Measurement Methods for the ESS Elliptical Cryomodules SAT at Lund Test Stand cryogenics, cryomodule, SRF, ECR 2819
 
  • N. Elias, X.T. Su
    ESS, Lund, Sweden
  • W. Gaj, P. Halczynski, M. Sienkiewicz, F.D. Skalka
    IFJ-PAN, Kraków, Poland
 
  The Site Acceptance Testing of all ESS elliptical cryomodules is done at Lund Test Stand. The cryogenic heat loads (static and dynamic) are an essential part of the acceptance criteria. We present complementary measurement methods for evaluating the cryogenic heat loads and discuss a qualitative comparison between them. We also present a summary of the results of these methods for one of the cryomodules.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK025  
About • Received ※ 07 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 10 July 2022
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THPOTK026 Development and Test of a Program for Automatic Conditioning of Room Temperature Cavities experiment, rfq, interface, software 2823
 
  • K. Kümpel, M. Märcz, H. Podlech, A. Rüffer, C. Wagner, S.R. Wagner
    IAP, Frankfurt am Main, Germany
  • H. Podlech
    HFHF, Frankfurt am Main, Germany
 
  The conditioning of room temperature cavities is a time-consuming process that can take several weeks and requires the supervision of experienced experimenters. To simplify this process for future cavities, a program is currently being developed at the IAP Frankfurt that will simplify the experimenter’s work and eventually take it over completely. This paper describes the basic setup of the program so far, as well as the tests performed on different cavities so far. In addition, an outlook for the next development steps and their application is given.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK026  
About • Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 16 June 2022
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THPOTK027 Temperature Dependent Effects on Quality Factor in C-band RF Cavities cryogenics, vacuum, shielding, electron 2826
 
  • J.R. Parsons, A. Fukasawa, G.E. Lawler, N. Majernik, J.B. Rosenzweig
    UCLA, Los Angeles, California, USA
 
  Funding: This work was supported by DOE Contract DE-SC0020409
Cryogenic operation and associated skin effects are encouraging fields of study for increasing RF gradients of beams within cavities and decreasing the required size for linear accelerators such as free electron lasers. Notably, a cavity’s RF quality factor Q, the ratio of the outgoing RF signal power to the input power, is theoretically multiplied by over 4 when subjected to cryogenic temperatures. Precise measurements of this Q factor require defining a cryostat unit, which consists of a high vacuum chamber, a coldhead, and MLI shielding. We optimized the cryostat by running several cool down tests at high vacuum, incorporating different geometries of MLI shielding to achieve the lowest possible temperatures. We then performed a low power C-band test after installing a cylindrical copper RF cavity to measure the Q factor. Finally, we improved stability and amplification within the chamber by installing edge welded bellows to the coldhead to reduce vibrations. These measurements provide a basis for the development of cryogenic infrastructure to sustain a cryogenic temperature environment for future RF applications.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK027  
About • Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 27 June 2022
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THPOTK032 A Vacuum System for the Milliampere Booster vacuum, simulation, linac, experiment 2833
 
  • R.G. Heine, C.L. Lorey
    KPH, Mainz, Germany
 
  The Milliampere Booster (MAMBO) is the injector linac for the Mainz Energy-recovering Superconducting Accelerator MESA. MESA is a multi-turn energy recovery linac with beam energies in the 100 MeV regime currently designed and built at Institut für Kernphysik (KPH) of Johannes Gutenberg-Universität Mainz. The main accelerator consists of two superconducting Rossendorf type modules, while the injector MAMBO relies on normal conducting technolgy. The MAMBO RF cavities are bi-periodic pi/2 structures that are about 2m long, each. In this paper we present the results of Molflow+ simulations of several setups of the vacuum system for MAMBO that differ in number of pumps, pumping speed and diameter of the pumping ports that are connected to the DN40 beam pipe.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK032  
About • Received ※ 07 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 24 June 2022
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THPOTK042 Non-Linear Phenomena Studies in High-Gradient RF Technology for Hadrontherapy at IFIC radiation, electron, accelerating-gradient, hadrontherapy 2865
 
  • P.M.R. Martinez-Reviriego, C. Blanch Gutiérrez, D. Esperante Pereira, J. Fuster, N. Fuster-Martínez, B. Gimeno, D. Gonzalez-Iglesias, P. Martín-Luna
    IFIC, Valencia, Spain
 
  High-Gradient accelerating cavities are one of the main research lines in the development of compact linear colliders. However, the operation of such cavities is currently limited by non-linear effects that are intensified at high electric fields, such as dark currents and radiation emission or RF breakdowns. A new normal-conducting High Gradient S-band Backward Travelling Wave accelerating cavity for medical application (v=0.38c) designed and constructed at CERN is being tested at IFIC. In this paper, we present experimental measurements and simulation of such non-linear effects. The main goal of these studies is to establish the viability of using these techniques in linear accelerators, in order to improve our understanding in such effects. The main goal of these studies is to determine the viability of using this techniques in linear accelerators for hadrontherapy treatments in hospitals.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK042  
About • Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 20 June 2022
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THPOTK051 Corrosion of Copper Components in the Deionized Water Cooling System of ALBA Synchrotron Light Source: Current Research Status and Challenges operation, synchrotron, experiment, radio-frequency 2891
 
  • M. Quispe, E. Ayas, J.J. Casas, C. Colldelram, Ll. Fuentes, J. Iglesias
    ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
  • A. Garcia
    La Romanica, Barberà del Vallès, Sabadell, Spain
 
  Currently, the ALBA Synchrotron Light Source is carrying out studies on corrosion in copper components of the deionized water cooling circuit. The preliminary studies, based on Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS), and X-Ray Diffraction (XRD) have shown the presence of intergranular, pitting, and generalized corrosion in the analyzed copper samples. The purpose of this paper is to present new advances in the field of this research, such as: the study of the influence of low velocity water flow in the cooling circuit on the current high dissolved oxygen content (> 6500 ppb), the results of corrosion products found in the cooling circuit, the description of the improper operation of the cooling circuit as a closed loop, and FEA studies of copper components in order to redefine the water flow velocity design criteria to values lower than 3 m/s and thus minimize corrosion by erosion. Finally, in order to attenuate the corrosion rate, preventive solutions are presented such as the viability to install an oxygen content degassing plant, new instrumentation for water quality monitorization, and installation of degassing equipment at strategic positions of the cooling circuit.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK051  
About • Received ※ 07 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 17 June 2022  
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THPOTK054 Proposal of a VHEE Linac for FLASH Radiotherapy linac, electron, gun, simulation 2903
 
  • L. Giuliano, F. Bosco, M. Carillo, D. De Arcangelis, A. De Gregorio, L. Ficcadenti, D. Francescone, G. Franciosini, M. Migliorati, A. Mostacci, L. Palumbo, V. Patera, A. Sarti
    Sapienza University of Rome, Rome, Italy
  • D. Alesini, A. Gallo, A. Vannozzi
    INFN/LNF, Frascati, Italy
  • M. Behtouei, L. Faillace, B. Spataro
    LNF-INFN, Frascati, Italy
  • M.G. Bisogni, F. Di Martino, J.H. Pensavalle
    INFN-Pisa, Pisa, Italy
  • G.A.P. Cirrone, G. Cuttone, G. Torrisi
    INFN/LNS, Catania, Italy
  • V. Favaudon, A. Patriarca
    Institut Curie - Centre de Protonthérapie d’Orsay, Orsay, France
  • S. Heinrich
    Institut Curie, Centre de Recherche, Orsay, France
 
  Translation of electron FLASH radiotherapy in clinical practice requires the use of high energy accelerators to treat deep tumours and Very High Electron Energy (VHEE) could represent a valid technique to achieve this goal. In this sce- nario, a VHEE FLASH linac is under study at the University La Sapienza of Rome (Italy) in collaboration with the Italian Institute for Nuclear Research (INFN) and the Curie Insti- tute (France). Here we present the preliminary results of a compact C-band system aiming to reach an high accelerating gradient and an high pulse current necessary to deliver high dose per pulse and ultra-high dose rate required for FLASH effect. We propose a system composed of a low energy high current injector linac followed by a modular section of high accelerating gradient structures. CST code is used to define the required LINAC’s RF parameters and beam dynamics simulations are performed using T-Step, ASTRA and GPT tracking codes.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK054  
About • Received ※ 17 May 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 10 July 2022
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THPOTK057 ESS RFQ Experimental Modal Analysis rfq, experiment, damping, software 2907
 
  • E. Trachanas, A. Bignami, N. Gazis, B. Jones
    ESS, Lund, Sweden
 
  The European Spallation Source-ESS, which is currently under construction and commissioning at Lund, Sweden is a neutron source that consists of a 2 GeV linear accelerator (LINAC) accelerating a proton beam to a solid Tungsten (W) target. The proton beam is produced by the Ion Source (ISRC) and transported through the Low Energy Beam Transport (LEBT) to the Radio Frequency Quadrupole (RFQ) that will then focus, bunch and accelerate it to 3.6 MeV. The RFQ beam commissioning started in October 2021, following the RF conditioning phase in summer 2021. This current work presents an experimental modal analysis performed on RFQ including the comparative analysis with the modal finite element simulation using the ANSYS software suite. Measurements were performed using accelerometer sensors connected to a data acquisition system excited with an impact hammer. Geophones were used in parallel to the modal measurements in order to monitor the seismic background of the accelerator tunnel. Acquired data were post-processed and analysed with dedicated software, juxtaposed with simulated results in order to determine the resonance frequencies, structural deformation patterns (mode shapes) and error margin between experimental and simulated results.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK057  
About • Received ※ 07 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 17 June 2022
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THPOMS005 Lab-Industry Collaboration: Industrialisation of A Novel Non-Interceptive Turn-Key Diagnostic System for Medical Applications instrumentation, diagnostics, proton, cyclotron 2945
 
  • S. Srinivasan, H. Bayle, E.T. Touzain
    BERGOZ Instrumentation, Saint Genis Pouilly, France
  • D. Bisiach, M. Cargnelutti, K. Roskar
    I-Tech, Solkan, Slovenia
  • P.-A. Duperrex
    PSI, Villigen PSI, Switzerland
 
  A novel non-interceptive beam current monitor prototype was successfully developed to measure the ultra-low beam currents (0.1-10 nA) with a 1 Hz measurement bandwidth at the Paul Scherrer Institute’s (PSI’s) proton radiation therapy facility, PROSCAN. The monitor resonance frequency is tuned to a harmonic of the beam pulse repetition rate, enabling a larger signal-to-noise ratio compared to those of broadband systems. Since the tuned frequency certainly differs for other facilities, such a system requires customisation. To enhance the application of the monitor to a turn-key system, a fast digitiser solution allowing (1 kHz data rate) streaming of measurements to various Control Systems is of importance as well. In this paper, we report on the industrial challenges associated, such as quality, reliability, repeatability and customisability, online monitoring, turn-key system, etc. in manufacturing a working novel prototype from a research environment. A fruitful collaboration between PSI, Bergoz Instrumentation, and Instrumentation Technologies is foreseen to make it happen, from a first-of-a-kind industrialised product to be tested in the lab, to a product line in a catalogue.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOMS005  
About • Received ※ 31 May 2022 — Revised ※ 11 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 29 June 2022
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THPOMS015 New Design of Cyclotron for Proton Therapy cyclotron, proton, extraction, acceleration 2973
 
  • O. Karamyshev
    JINR, Dubna, Moscow Region, Russia
 
  An innovative approach to a design of cyclotron allows to produce cheaper and more power efficient cyclotrons for medical and industrial application. A design of 230 MeV proton cyclotron for proton therapy, using this approach is presented. The cyclotron is one of the line of cyclotrons from 15 to 230 MeV, that uses same magnet field level and RF frequency and utilises many identical solutions within the lineup to make it cheaper to produce and run.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOMS015  
About • Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 15 June 2022
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THPOMS016 A New Design of PET Cyclotron cyclotron, proton, vacuum, acceleration 2977
 
  • O. Karamyshev
    JINR, Dubna, Moscow Region, Russia
 
  An innovative approach to a design of cyclotron allows to produce cheaper and more power efficient cyclotrons for medical and industrial application. 15 MeV cyclotron for PET (and other) isotopes production are widely used and in very high demand. In this paper a design of a very compact and cheap to build and to run cyclotron is presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOMS016  
About • Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 10 July 2022
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THPOMS017 MSC230 Superconducting Cyclotron for Proton Therapy cyclotron, proton, extraction, acceleration 2981
 
  • O. Karamyshev, K. Bunyatov, S. Gurskiy, G.G. Hodshibagijan, G.A. Karamysheva, D. Nikiforov, M.S. Novikov, D. Popov, V.M. Romanov, G. Shirkov, S.G. Shirkov, A.A. Sinitsa, G.V. Trubnikov, S. Yakovenko
    JINR, Dubna, Moscow Region, Russia
  • V.A. Gerasimov, I.D. Lyapin, V. Malinin
    JINR/DLNP, Dubna, Moscow region, Russia
 
  Superconducting cyclotron MSC230 is dedicated for acceleration the proton beam to 230 MeV for medico-biological research. MSC230 is an isochronous four-sector compact cyclotron with a magnetic field in the center of 1.7 T. Acceleration is performed at the fourth harmonic mode of the accelerating radio-frequency (RF) system consisting of four cavities located in the cyclotron valleys. The accelerator will use an internal Penning type source with a hot cathode. Extraction is carried out by an electrostatic deflector located in the gap between sectors and two passive magnetic channels. The current status of the project is discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOMS017  
About • Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 04 July 2022
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THPOMS052 Magnetic Field Shield for SC-Cavity with Thin Nb Sheet niobium, shielding, experiment, cryogenics 3090
 
  • Y. Iwashita, Y. Kuriyama
    Kyoto University, Research Reactor Institute, Osaka, Japan
  • Y. Fuwa
    JAEA/J-PARC, Tokai-mura, Japan
  • H. Tongu
    Kyoto ICR, Uji, Kyoto, Japan
 
  Funding: This work was partly supported by JSPS KAKENHI Grant Number 19K21877.
Shielding the superconducting accelerating cavity made of niobium from the weak environmental magnetic field is an important subject. Niobium is a type-II superconductor, which traps the environmental magnetic flux in the material during the superconducting transition, resulting in increase of residual resistance and heating during operation during operation. Shielding from a weak magnetic field is essential for high performance operations. A magnetic shielding method that uses the diamagnetism of superconducting materials instead of magnetic flux absorption by high magnetic permeability materials is discussed.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOMS052  
About • Received ※ 14 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 18 June 2022
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FRIXGD1 Status and Prospects in Fast Beam-Based Feedbacks feedback, kicker, pick-up, hadron 3112
 
  • W. Höfle
    CERN, Meyrin, Switzerland
 
  Fast beam-based Feedback systems play an important role in circular accelerators to mitigate instabilities and reduce the impact of injection oscillations and perturbations on beam quality, both in the longitudinal and transverse planes. The status and prospects of such beam-based feedback systems for circular accelerators are reviewed. This includes progress towards the fundamental limits in noise and feedback gain and the possibilities of modern digital systems to extract large amounts of data that can be used to characterise beam properties. The talk concentrates on machines with hadrons and gives an outlook on possible developments for future accelerator projects under study.  
slides icon Slides FRIXGD1 [3.562 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-FRIXGD1  
About • Received ※ 08 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 20 June 2022  
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FRIXSP1 Low-Emittance Compact RF Electron Gun with a Gridded Thermionic Cathode gun, electron, emittance, cathode 3124
 
  • T. Asaka
    JASRI/SPring-8, Hyogo-ken, Japan
 
  A new type of rf electron gun has been developed to generate a stable electron beam with a low-emittance of ~1 um.rad, that can be injected into SX-FEL and DLSR, without using a large UV laser system nor an ultra-high voltage pulsers. This electron gun consists of a 50 kV pulsed gun equipped with a commercially available thermionic cathode with grid and a 238-MHz acceleration cavity driven by a 42 kW solid-state amplifier. The system is simple, stable, robust, and of easy-maintenance. To obtain a "grid-transparent" condition, the cathode voltage and the control grid voltage are optimized not to distort the electric field near the grid. To avoid the emittance growth due to the space charge effect, the gun and a special magnetic lens are embedded in the 238-MHz cavity at the shortest distance, and the beam energy is immediately accelerated to 500 kV. The first model of this electron gun has been operated as the 1 GeV injector of the NewSUBARU storage ring. The same electron gun will also be used in the injector linac of the 3 GeV light source under construction in Japan. The talk is expected to include the concept, overall design and the achieved performance.  
slides icon Slides FRIXSP1 [2.893 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-FRIXSP1  
About • Received ※ 08 June 2022 — Revised ※ 17 June 2022 — Accepted ※ 19 June 2022 — Issue date ※ 23 June 2022
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FROXSP1 20-Year Collaboration on Synchrotron RF Between CERN and J-PARC synchrotron, proton, radiation, operation 3130
 
  • C. Ohmori
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
  • M. Brucoli, M. Brugger, H. Damerau, S. Danzeca, M.M. Paoluzzi, C. Rossi
    CERN, Meyrin, Switzerland
  • K. Hasegawa, Y. Morita, Y. Sugiyama, M. Yoshii
    KEK, Tokai, Ibaraki, Japan
  • H. Okita, M.J. Shirakata, F. Tamura
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
 
  KEK/J-PARC and CERN started the collaboration on the RF systems of Low Energy Ion Ring to use magnetic alloy loaded cavities in 2002 for heavy ion collision program at LHC. It was an exchange of our expertise on the wideband cavities and high-power solid-state amplifiers. This paper summarizes the 20-year collaboration which includes many synchrotrons of both facilities: J-PARC Rapid Cycling Synchrotron and Main Ring, CERN Proton Synchrotron, PS Booster, Antiproton Decelerator, Extra Low Energy Antiproton ring and MedAustron. By the improvements of cavity core using the magnetic annealing, field gradient of cavity and compactness were improved to fit the requirements for LHC Injector Upgrade (LIU)program. Radiation-hard and compact high-power solid-state amplifiers were also developed for LIU and future accelerator improvements.  
slides icon Slides FROXSP1 [8.210 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-FROXSP1  
About • Received ※ 07 June 2022 — Revised ※ 17 June 2022 — Accepted ※ 19 June 2022 — Issue date ※ 25 June 2022
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FRPLYGD1 Towards Efficient Particle Accelerators - A Review collider, cryogenics, radiation, luminosity 3141
 
  • M. Seidel
    PSI, Villigen PSI, Switzerland
 
  Sustainability has become an important aspect of all human activities, and also for accelerator driven research infrastructures. For new facilities it is mandatory to optimize power consumption and overall sustainability. This presentation will give an overview of the power efficiency of accelerator concepts and relevant technologies. Conceptual aspects will be discussed for proton driver accelerators, light sources and particle colliders. Several accelerator technologies are particularly relevant for power efficiency. These are utilized across the various facility concepts and include superconducting RF and cryogenic systems, RF sources, energy efficient magnets, conventional cooling and heat recovery. Power efficiency has been a topic in the European programs EUCARD-2, ARIES and the ongoing I.FAST project and the documentation of these programs is a related source of information.  
slides icon Slides FRPLYGD1 [4.531 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-FRPLYGD1  
About • Received ※ 07 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 29 June 2022
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