Electron Accelerators and Applications
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Nanoparticle Assisted Laser-Wakefield Acceleration of Electron Beams to 10 Gev at the Texas Petawatt Laser  
  • B.M. Hegelich
    The University of Texas at Austin, Austin, Texas, USA
  We report peak electron energies beyond 10 GeV from a proof-of-principle experiment of laser wakefield electron acceleration with a Petawatt-class laser in a 10 cm long gas cell filled with helium mixed with aluminum nanoparticles. Compared with other wakefield acceleration schemes, our scheme is straightforward since it requires only a gas cell and a source of nanoparticles for electron injection. No external guiding or heating mechanisms are employed. The nanoparticle-assisted laser wakefield acceleration can control all the electron beam parameters: charge, energy spread, energy, emittance, and the number of bunches in the beam. Bunch charges are on the order of a few nanocoulomb for the whole beam and in the 100pC range in the high energy part, an order of magnitude increase over previous results at >5 GeV. We demonstrate shots with percent-level narrow energy spread at multi-GeV energies as well as varying numbers of electron bunches. This new method therefore shows great potential to support the further development of laser-plasma-based electron acceleration.  
slides icon Slides WE1AA04 [8.972 MB]  
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THPOPA01 FLASH2020+ Upgrade - Modification of RF Power Waveguide Distribution for the Free-electron Laser FLASH at DESY 747
  • B. Yildirim, S. Choroba, V.V. Katalev, P. Morozov, Y. Nachtigal, N.V. Vladimirov
    DESY, Hamburg, Germany
  The goal of FLASH2020+ upgrade is to increase the energy of the FLASH accelerator, which allows the use of even shorter wavelengths, which, in turn, will allow new research. For this purpose, during the shutdown in 2022, two superconducting accelerator modules for ACC2 and ACC3 will be replaced by new ones. To fully realize the potential of these cryomodules XFEL type of waveguide distributions will be installed on them. In addition, the existing ACC4 and ACC5 cryomodules will also be equipped with the new waveguide distributions, similar XFEL type. These waveguide distributions will be modified and improved so that the machine can operate with the maximum energy due to individual power supply for each cavity. Furthermore, three RF stations will receive a new klystron waveguide distribution, which will improve the reliability of all systems. The specific waveguide distributions have been developed, produced and tested at the Waveguide Assembly and Test Facility (WATF) at DESY. All together will lead to increasing the electron beam energy from 1.25 to 1.35 GeV. This paper presents data on the production and tuning of waveguide distribution systems for the FLASH2020+ upgrade at DESY.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOPA01  
About • Received ※ 16 August 2022 — Revised ※ 28 August 2022 — Accepted ※ 02 September 2022 — Issue date ※ 02 September 2022
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THPOPA04 Unfolding of Bremsstrahlung Photons Energy Spectra Emitted from Electron Cyclotron Resonance Ion Source 750
  • M.J. Kumwenda
    University of Dar es Salaam, Dar es Salaam, Tanzania
  • J.-K. Ahn
    Korea University, Seoul, Republic of Korea
  The aim of present study is to determine end-point energies of the bremsstrahlung photons energy spectra emitted from 28-GHz ECRIS by using inverse-matrix unfold method. Azimuthal angular distribution of the bremsstrahlung photons from 28-GHz ECRIS were measured at Busan Center of KBSI. Gamma-ray detection system consists of three round type NaI(Tl) scintillation detectors positioned 62 cm radially from the beam axis and another detector placed at the extraction port for monitoring photon intensity along the beam axis. Bremsstrahlung photons energy spectra were measured at six azimuthal angles at RF power of 1 kW. Monte Carlo simulation based on Geant4 package was performed to take the geometrical acceptance and energy-dependent detection efficiency into account due to large non-uniformity in the material budget. We extracted true bremsstrahlung energy spectra using the inverse-matrix unfolding method. The end-point energies of the bremsstrahlung photons after application of deconvolution method were found to be 1.320±0.050 MeV, 1.530±0.070 MeV, 1.540±0.070 MeV, 1.690±0.030 MeV, 1.530±0.070 MeV and 1.690±0.030 MeV for 0°, 30°, 60°, 90°, 120° and 330°, respectively.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOPA04  
About • Received ※ 23 August 2022 — Revised ※ 31 August 2022 — Accepted ※ 09 September 2022 — Issue date ※ 23 September 2022
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THPOPA05 Status of the CLEAR User Facility at CERN and its Experiments 753
  • R. Corsini, W. Farabolini, A. Malyzhenkov, V. Rieker
    CERN, Meyrin, Switzerland
  • P. Korysko
    Oxford University, Physics Department, Oxford, Oxon, United Kingdom
  • K.N. Sjobak
    University of Oslo, Oslo, Norway
  The CERN Linear Accelerator for Research (CLEAR) at CERN is a versatile user facility providing a 200 MeV electron beam for accelerator R&D, irradiation studies for space, and medical applications. After successful operation in 2017-2020, CLEAR running was extended in 2021 for another 5-year period. In the paper we give a status of the facility, outlining recent progress in beam performance and hardware improvements. We report on beam operation over the last years and review the main results of experimental activities. Finally, we discuss the planned upgrades together with the proposed future experimental program.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOPA05  
About • Received ※ 24 August 2022 — Revised ※ 28 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 01 September 2022
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THPOPA09 High Stability Klystron Modulator for Commercial Accelerator Application 762
  • M.K. Kempkes, M. Benjnane, C. Chipman, M.P.J. Gaudreau, A. Heindel, Z. Ruan, R.E. Simpson, H. von Kelsch
    Diversified Technologies, Inc., Bedford, Massachusetts, USA
  Diversified Technologies, Inc. (DTI) designed and developed a high stability modulator system for a commercial linear accelerator application. The DTI modulator delivers significant advantages in klystron performance through highly reliable functionality as well as flicker- and droop-free operation from 50-500 microseconds up to 400 Hz (duty limited). The main assemblies on the DTI system consist of a controls rack, high voltage power supply (HVPS), modulator, and cooling manifolds for the modulator, high voltage power supply and klystron tube. Two HVPS (upgradeable to four) provide stable and accurate DC voltage which is used to drive a CPI VKP-8352C UHF-band pulsed klystron for the linear accelerator. A solid state series switch, based on DTI’s patented design, provides both pulse control and arc protection to the klystron. Operating with four HVPS, the DTI modulator is able to operate at a maximum average power of ~750 kW at 105 kV, 47 A nominal. At the end of the initial contract, DTI provided two systems and a total of four HVPS (two of which are used with each system).  
poster icon Poster THPOPA09 [0.736 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOPA09  
About • Received ※ 19 August 2022 — Revised ※ 22 August 2022 — Accepted ※ 28 August 2022 — Issue date ※ 15 September 2022
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