Author: Giribono, A.
Paper Title Page
MOPOMS019 The New SPARC_LAB RF Photo-Injector 671
 
  • D. Alesini, M.P. Anania, M. Bellaveglia, A. Biagioni, F. Cardelli, G. Costa, M. Del Franco, G. Di Pirro, L. Faillace, M. Ferrario, G. Franzini, A. Gallo, A. Giribono, L. Piersanti, L. Sabbatini, A. Stella, A. Vannozzi
    INFN/LNF, Frascati, Italy
  • A. Battisti, E. Chiadroni, G. Di Raddo, A. Liedl, V.L. Lollo, L. Pellegrino, R. Pompili, S. Romeo, V. Shpakov, C. Vaccarezza, F. Villa
    LNF-INFN, Frascati, Italy
  • M. Carillo, E. Chiadroni
    Sapienza University of Rome, Rome, Italy
  • A. Cianchi, M. Galletti
    Università di Roma II Tor Vergata, Roma, Italy
 
  A new RF photo-injector has been designed, realized and successfully installed at the SPARC_LAB facility (INFN-LNF, Frascati, Rome). It is based on a 1.6 cell RF gun fabricated with the new brazing free technology recently developed at the National Laboratories of Frascati. The electromagnetic design has been optimized to have a full compensation of the dipole and quadrupole field components introduced by the coupling hole with an improvement of the effective pumping speed with two added pumping ports. The gun is overcoupled (\beta=2) to reduce the filling time and to allow the operation with short RF pulses. The overall injector integrates a new solenoid with a remote control of the transverse position and a variable skew quadrupole for the compensation of residual quadrupole field components. It also allows an on axis laser injection system with the last mirror in air, and the possibility of a future integration of an X/C band cavity linearizer. In the paper we report the main characteristics of the electromagnetic and mechanical design and the low and high power test results that shows the extremely good perfomances of the new device.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS019  
About • Received ※ 07 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 26 June 2022
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MOPOMS020 Dark Current Studies for a High Gradient SW C-Band RF Gun 675
 
  • F. Cardelli, D. Alesini, L. Faillace, A. Giribono, A. Vannozzi
    INFN/LNF, Frascati, Italy
  • G. Di Raddo
    LNF-INFN, Frascati, Italy
  • T.G. Lucas
    PSI, Villigen PSI, Switzerland
 
  It is now well-established that for the generation of very high brightness beams, required for fourth generation light sources, it is highly advantageous to use injectors based on Radiofrequency photo-guns with very high peak electric fields on the cathode (>120 MV/m). This very high surface electric field leads to the generation of undesirable electrons due to the field emission effect. The emitted electrons can be captured and propagate along the Linac forming a dark current beam, leading to background radiation that can damage the instrumentation and radioactivate components. Consequently, it is important that the emission of these electrons, and their subsequent transportation, is carefully evaluated. Recently, in the framework of the I-FAST project, a high gradient, standing wave, C-band (5712 MHz) RF photogun has been designed and will be realized soon. In this paper, the results of dark current studies and simulations are illustrated. The transport efficiency and the spectrum of the dark current have been evaluated by Particle-In-Cell simulations for different cathode peak field values considering also the effect of the focusing solenoid on the dark current beam.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS020  
About • Received ※ 08 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 30 June 2022
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MOPOMS021 The New C Band Gun for the Next Generation RF Photo-Injectors 679
 
  • D. Alesini, M. Ferrario, A. Giribono, A. Gizzi, L. Piersanti, A. Vannozzi
    INFN/LNF, Frascati, Italy
  • F. Cardelli, G. Di Raddo, L. Faillace, S. Lauciani, A. Liedl, L. Pellegrino, C. Vaccarezza
    LNF-INFN, Frascati, Italy
  • G. Castorina
    AVO-ADAM, Meyrin, Switzerland
  • M. Croia
    ENEA Casaccia, Roma, Italy
  • L. Ficcadenti
    INFN-Roma, Roma, Italy
  • G. Pedrocchi
    SBAI, Roma, Italy
 
  Funding: European Union’s Horizon 2020 Research and Innovation programme under GA No 101004730 and INFN Commission V.
RF photo-injectors are widely used in modern facilities, especially in FEL, as very low-emittance and high-brightness electron sources. Presently, the RF technology mostly used for RF guns is the S band (3 GHz) with typical cathode peak fields of 80-120 MV/m and repetition rates lower than 120 Hz. There are solid reasons to believe that the frequency step-up from S band to C band (6 GHz) can provide a strong improvement of the beam quality due to the potential higher achievable cathode field (>160 MV/m) and higher repetition rate (that can reach the kHz level). In the contest of the European I.FAST project, a new C band gun has been designed and will be realized and tested. It is a 2.5 cell standing wave cavity with a four port mode launcher, designed to operate with short RF pulses (<300 ns) and cathode peak field larger than 160 MV/m. In the paper we present the electromagnetic and thermo-mechanical design and the results of the prototyping activity and rf measurements.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS021  
About • Received ※ 07 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 28 June 2022
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MOPOMS023 Start-to-End Beam-Dynamics Simulations of a Compact C-Band Electron Beam Source for High Spectral Brilliance Applications 687
 
  • L. Faillace, M. Behtouei, B. Spataro, C. Vaccarezza
    LNF-INFN, Frascati, Italy
  • R.B. Agustsson, I.I. Gadjev, S.V. Kutsaev, A.Y. Murokh
    RadiaBeam, Marina del Rey, California, USA
  • F. Bosco, M. Carillo, L. Giuliano, M. Migliorati, A. Mostacci, L. Palumbo
    Sapienza University of Rome, Rome, Italy
  • D.L. Bruhwiler
    RadiaSoft LLC, Boulder, Colorado, USA
  • O. Camacho, A. Fukasawa, N. Majernik, J.B. Rosenzweig, O. Williams
    UCLA, Los Angeles, California, USA
  • A. Giribono
    INFN/LNF, Frascati, Italy
  • S.G. Tantawi
    SLAC, Menlo Park, California, USA
 
  Funding: This work is partially supported by DARPA under the Contract No. HR001120C0072, by DOE Contract DE-SC0009914, DOE Contract DE-SC0020409, and by the National Science Foundation Grant No. PHY-1549132.
Proposals for new linear accelerator-based facilities are flourishing world-wide with the aim of high spectral brilliance radiation sources. Most of these accelerators are based on electron beams, with a variety of applications in industry, research and medicine such as colliders, free-electron lasers, wake-field accelerators, coherent THz and inverse Compton scattering X/’ sources as well as high-resolution diagnostics tools in biomedical science. In order to obtain high-quality electron beams in a small footprint, we present the optimization design of a C-band linear accelerator machine. Driven by a novel compact C-band hybrid photoinjector, it will yield ultra-short electron bunches of few 100’s pC directly from injection with ultra-low emittance, fraction of mm-mrad, and a few hundred fs length simultaneously, therefore satisfying full 6D emittance compensation. The normal-conducting linacs are based on a novel high-efficiency design with gradients up to 50 MV/m. The beam maximum energy can be easily adjusted in the mid-GeV’s range. In this paper, we discuss the start-to-end beam-dynamics simulations in details.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS023  
About • Received ※ 07 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 03 July 2022
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WEPOMS045 Modeling and Mitigation of Long-Range Wakefields for Advanced Linear Colliders 2350
SUSPMF071   use link to see paper's listing under its alternate paper code  
 
  • F. Bosco, M. Carillo, L. Giuliano, M. Migliorati, A. Mostacci, L. Palumbo
    Sapienza University of Rome, Rome, Italy
  • O. Camacho, A. Fukasawa, N. Majernik, J.B. Rosenzweig
    UCLA, Los Angeles, California, USA
  • E. Chiadroni, B. Spataro, C. Vaccarezza
    LNF-INFN, Frascati, Italy
  • L. Faillace, A. Giribono
    INFN/LNF, Frascati, Italy
 
  Funding: This work is supported by DARPA under Contract N.HR001120C0072, by DOE Contract DE-SC0009914 and DE-SC0020409, by the National Science Foundation Grant N.PHY-1549132 and by INFN.
The luminosity requirements of TeV-class linear colliders demand use of intense charged beams at high repetition rates. Such features imply multi-bunch operation with long current trains accelerated over the km length scale. Consequently, particle beams are exposed to the mutual parasitic interaction due to the long-range wakefields excited by the leading bunches in the accelerating structures. Such perturbations to the motion induce transverse oscillations of the bunches, potentially leading to instabilities such as transverse beam break-up. Here we present a dedicated tracking code that studies the effects of long-range transverse wakefield interaction among different bunches in linear accelerators. Being described by means of an efficient matrix formalism, such effects can be included while preserving short computational times. As a reference case, we use our code to investigate the performance of a state-of-the-art linear collider currently under design and, in addition, we discuss possible mitigation techniques based on frequency detuning and damping.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS045  
About • Received ※ 20 May 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 10 July 2022
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