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MOPORI04 A Gas Jet Beam Halo Monitor for LINACs simulation, electron, experiment, extraction 227
 
  • O. Stringer, N. Kumar, C.P. Welsch, H.D. Zhang
    The University of Liverpool, Liverpool, United Kingdom
  • N. Kumar, O. Stringer, C.P. Welsch, H.D. Zhang
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
 
  The gas jet beam profile monitor is a non-invasive beam monitor that is currently being commissioned at the Cockcroft Institute. It utilises a supersonic gas curtain which traverses the beam perpendicular to its propagation and measures beam-induced ionisation interactions of the gas. A 2D transverse beam profile image is created by orientating the gas jet 45 degrees to obtain both X and Y distributions of the beam. This paper builds upon previously used single-slit skimmers and improves their ability to form the gas jet into a desired distribution for imaging beam halo. A skimmer device removes off-momentum gas particles and forms the jet into a dense thin curtain, suitable for transverse imaging of the beam. The use of a novel double-slit skimmer is shown to provide a mask-like void of gas over the beam core, increasing the relative intensity of the halo interactions for measurement. Such a non-invasive monitor would be beneficial to linacs by providing real time beam characteristic measurements without affecting the beam. More specifically, beam halo behaviour is a key characteristic associated with beam losses within linacs.  
poster icon Poster MOPORI04 [1.066 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI04  
About • Received ※ 24 August 2022 — Revised ※ 26 August 2022 — Accepted ※ 31 August 2022 — Issue date ※ 13 October 2022
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TH1AA02 Developments Towards FRIB Upgrade to 400 MeV/u for Heaviest Uranium Ions cavity, cryomodule, ECR, linac 653
 
  • K.E. McGee, K. Elliott, A. Ganshyn, W. Hartung, S.H. Kim, P.N. Ostroumov, J.T. Popielarski, L. Popielarski, A. Taylor, T. Xu
    FRIB, East Lansing, Michigan, USA
  • G.V. Eremeev, F. Furuta, M. Martinello, O.S. Melnychuk, A.V. Netepenko
    Fermilab, Batavia, Illinois, USA
  • B.M. Guilfoyle, M.P. Kelly, T. Reid
    ANL, Lemont, Illinois, USA
 
  High-Q0 medium-velocity (beta opt = 0.6) 5-cell elliptical cavities for superconducting linacs are critical technology for advancing current and future projects such as the Proton Improvement Plan II linac and the proposed energy upgrade of Michigan State University’s Facility For Rare Isotope Beams linac, FRIB400. Previous work established the validity of the novel geometry of the FRIB400 prototype 644 MHz 5-cell elliptical β = 0.65 cavities for future high Q0 development. In collaboration with FNAL, two leading-edge high-Q0 recipes, N-doping and Mid-T baking, were tested in the 5-cell format. 2/0 N-doping + cold electropolishing was successful at achieving FRIB400 and PIP-II Q0 requirements, achieving an unprecedented 3.8 x 1010 at 17.5 MV/m, satisfying the FRIB400 Q0 requirements by 1.75 times in a low-gauss environment. Mid-T baking exceeded FRIB400 Q0 requirements by 1.4 times, and benefitted from decreased residual resistance compared to the N-doped cavity test. Systematic ultrasonic thickness measurements in single-cell revealed bulk (150 microns) EP with the modified EP tool is consistent across the inner surfaces of the cavity walls.  
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slides icon Slides TH1AA02 [44.708 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TH1AA02  
About • Received ※ 11 August 2022 — Revised ※ 22 August 2022 — Accepted ※ 23 September 2022 — Issue date ※ 14 October 2022
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