Author: Mazzoni, S.
Paper Title Page
MOPAB279 Non-Invasive Beam Profile Monitoring for the HL-LHC Hollow Electron Lens 884
 
  • A. Salehilashkajani, N. Kumar, O. Sedláček, C.P. Welsch, H.D. Zhang
    The University of Liverpool, Liverpool, United Kingdom
  • M. Ady, N.S. Chritin, N. Jens, O.R. Jones, R. Kersevan, T. Lefèvre, S. Mazzoni, G. Papazoglou, A. Rossi, G. Schneider, R. Veness
    CERN, Meyrin, Switzerland
  • P. Forck, S. Udrea
    GSI, Darmstadt, Germany
  • N. Kumar, O. Sedláček, C.P. Welsch, H.D. Zhang
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
 
  Funding: This work was supported by the HL-LHC-UK phase II project funded by STFC under Grant Ref: ST/T001925/1 and the STFC Cockcroft core grant No. ST/G008248/1.
A Hollow Electron Lens (HEL) is currently under development for the High-Luminosity upgrade of the Large Hadron Collider (HL-LHC). In this device, a hollow electron beam co-propagates with a central proton beam and provides active halo control in the LHC. To ensure the concentricity of the two beams, a non-invasive diagnostic instrument is currently being commissioned. This instrument is a compact version of an existing prototype that leverages beam induced fluorescence with supersonic gas curtain technology. This contribution includes the design features of this version of the monitor, recent progress, and future plans for tests at the Cockcroft Institute and the electron lens test stand at CERN.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB279  
About • paper received ※ 18 May 2021       paper accepted ※ 15 June 2021       issue date ※ 02 September 2021  
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MOPAB283 Simulations of Space-Charge and Guiding Fields Effects on the Performance of Gas Jet Profile Monitoring 898
 
  • O. Sedláček, N. Kumar, A. Salehilashkajani, C.P. Welsch, H.D. Zhang
    The University of Liverpool, Liverpool, United Kingdom
  • P. Forck, S. Udrea
    GSI, Darmstadt, Germany
  • N. Kumar, A. Salehilashkajani, O. Sedláček, C.P. Welsch, H.D. Zhang
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • S. Mazzoni, O. Sedláček
    CERN, Geneva, Switzerland
 
  Gas jet based profile monitors inject a usually curtain shaped gas jet across a charged particle beam and exploit the results of the minimally invasive beam-gas interaction to provide information about the beam’s transversal profile. Such monitor will be installed as part of the High Luminosity LHC upgrade at CERN in the Hollow Electron Lens (HEL). The HEL represents a new collimation stage increasing the diffusion rate of halo particles by placing a high intensity hollow electron beam concentrically around the LHC beam. The gas jet monitor will use the fluorescence radiation resulting due to the beam-gas interaction to create an image of the profiles of both hollow electron and LHC beams However, the high beam space-charge and strong guiding magnetic field of the electron beam cause significant displacements of the excited molecules, as they are also ionized, and thus image distortions. This work presents preliminary simulation results showing expected fluorescence images of the hollow electron profile as affected by space-charge and guiding fields using simulation tools such as IPMsim. The influence of the estimated electron beam and gas jet curtain parameters are investigated.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB283  
About • paper received ※ 18 May 2021       paper accepted ※ 28 July 2021       issue date ※ 19 August 2021  
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TUPAB283 Feasibility Study of ChDR Diagnostic Device in the LHC 2139
 
  • K. Łasocha
    Jagiellonian University, Kraków, Poland
  • M. Bergamaschi, M. Krupa, K. Łasocha, T. Lefèvre, S. Mazzoni, N. Mounet, E. Senes
    CERN, Geneva, Switzerland
  • D.M. Harryman
    JAI, Egham, Surrey, United Kingdom
  • P. Karataev
    Royal Holloway, University of London, Surrey, United Kingdom
  • A. Potylitsyn
    TPU, Tomsk, Russia
  • A. Schloegelhofer
    TU Vienna, Wien, Austria
 
  In recent years Cherenkov Diffraction Radiation (ChDR) has been reported as a phenomenon suitable for various types of particle accelerator diagnostics. As it would typically work best for highly relativistic beam, past studies and experiments have been mostly focusing on the lepton machines. This contribution investigates the prospects on the utilization of ChDR as a diagnostic tool for the Large Hadron Collider (LHC). Based on theoretical considerations and simulation results we estimate the properties of the expected radiation, both in the incoherent and coherent domain, and we compare them with the requirements of the existing diagnostic systems. We also address the potential problem of the use of dielectric radiators in circular machines, where secondary electrons could potentially lead to the creation of electron clouds inside the beam pipe that may affect the radiator.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB283  
About • paper received ※ 14 May 2021       paper accepted ※ 18 June 2021       issue date ※ 02 September 2021  
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THPAB284 Analytical and Numerical Characterization of Cherenkov Diffraction Radiation as a Longitudinal Electron Bunch Profile Monitor for AWAKE Run 2 4355
 
  • C. Davut, G.X. Xia
    UMAN, Manchester, United Kingdom
  • O. Apsimon
    The University of Liverpool, Liverpool, United Kingdom
  • O. Apsimon
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • P. Karataev
    Royal Holloway, University of London, Surrey, United Kingdom
  • P. Karataev
    JAI, Egham, Surrey, United Kingdom
  • T. Lefèvre, S. Mazzoni
    CERN, Geneva, Switzerland
 
  In this paper, CST simulations of the coherent Cherenkov Diffraction Radiation with a range of parameters for different dielectric target materials and geometries are discussed and compared with the theoretical investigation of the Polarization Current Approach to design a prototype of a radiator for the bunch length/profile monitor for AWAKE Run 2. It was found that the result of PCA theory and CST simulation are consistent with each other regarding the shape of the emitted ChDR cone.
* Karlovets, D. V. (2011). JETP, 113(1), 27-45.
** Shevelev, M. V., & Konkov, A. S. (2014). JETP, 118(4), 501-511.
*** Curcio, A., et al.(2020). PRAB, 23(2), 022802.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB284  
About • paper received ※ 16 May 2021       paper accepted ※ 14 July 2021       issue date ※ 10 August 2021  
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FRXC02
Non Invasive Bunch Length Measurements Exploiting Cherenkov Diffraction Radiation  
 
  • S. Mazzoni, M. Bergamaschi, R. Corsini, A. Curcio, W. Farabolini, D. Gamba, L. Garolfi, A. Gilardi, R. Kieffer, M. Krupa, T. Lefèvre, E. Senes, M. Wendt
    CERN, Geneva, Switzerland
  • A. Curcio
    NSRC SOLARIS, Kraków, Poland
  • C. Davut, G.X. Xia
    UMAN, Manchester, United Kingdom
  • W. Farabolini
    CEA-DRF-IRFU, France
  • K.V. Fedorov, P. Karataev, K. Lekomtsev, C. Pakuza
    JAI, Oxford, United Kingdom
  • K.V. Fedorov, A. Potylitsyn
    TPU, Tomsk, Russia
  • J. Gardelle
    CEA, LE BARP cedex, France
  • P. Karataev
    Royal Holloway, University of London, Surrey, United Kingdom
  • T.H. Pacey, Y.M. Saveliev
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • A. Schloegelhofer
    TU Vienna, Wien, Austria
  • E. Senes
    Oxford University, Physics Department, Oxford, Oxon, United Kingdom
 
  Cherenkov Diffraction Radiation (ChDR) refers to the emission of broadband electromagnetic radiation which occurs when a charged particle propagates at relativistic speed in the vicinity of a dielectric material. At variance with the better-known Cherenkov radiation, ChDR is a non-invasive technique, that is the particle beam does not impinge on the dielectric radiator. ChDR also possesses other interesting features like a relatively high light yield, a broadband spectrum of emission and the emission at a relatively large angle with respect to the beam trajectory. Due to its potential, CERN initiated over the last few years several studies on ChDR-based diagnostics techniques. In this contribution I will focus on the exploitation of ChDR for non-invasive bunch length measurement, from proof of principle tests performed at the CLEAR facility at CERN and CLARA at Daresbury laboratory to current developments for experiments and facilities such as AWAKE and FCC  
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