TUBO —  Transverse Profile and Emittance Monitors   (10-Sep-19   11:00—13:00)
Chair: T.M. Mitsuhashi, KEK, Ibaraki, Japan
Paper Title Page
Screen materials for high precision measurements  
  • B. Walasek-Höhne, P. Forck
    GSI, Darmstadt, Germany
  • R. Ischebeck
    PSI, Villigen PSI, Switzerland
  • G. Kube
    DESY, Hamburg, Germany
  Funding: This project has received funding from the European Union’s Horizon 2020 programme under Grant Agreement No 730871.
Scintillation screens made of various inorganic materials are widely used for transverse beam profile diagnostics at all kinds of accelerators. The monitor principle is based on the particles’ energy loss and its conversion to visible light. The resulting light spot is a direct image of the two-dimensional beam distribution. For large beam sizes standard optical techniques can be applied, while for small beam sizes dedicated optical arrangements have to be used to prevent for image deformations. In the modern linac based light sources scintillator usage serves as an alternative way to overcome limitations related to coherent OTR emission. Radiation damages and intensity based saturation effects, in dependence of the screen material, have to be modelled. In this talk, an introduction to the scintillation mechanism in inorganic materials will be given including practical demands and limitations. An overview on actual applications at hadron and electron accelerators will be discussed as summary of the Joint ARIES-ADA Workshop on ’Scintillation Screens and Optical Technology for transverse Profile Measurements’ held in Kraków, Poland.
slides icon Slides TUBO01 [27.172 MB]  
TUBO02 FERMI-PSI Collaboration on Nano-Fabricated Wire-Scanners With Sub-Micrometer Resolution: Developments and Measurements. -1
  • G.L. Orlandi, S. Borrelli, Ch. David, E. Ferrari, V. Guzenko, B. Hermann, O. Huerzeler, R. Ischebeck, C. Lombosi, C. Ozkan Loch, E. Prat
    PSI, Villigen PSI, Switzerland
  • N. Cefarin, S. Dal Zilio, M. Lazzarino
    IOM-CNR, Trieste, Italy
  • M. Ferianis, G. Penco, M. Veronese
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  Wire-scanners with micrometer resolution are in operation at SwissFEL and FERMI for measurements of the beam emittance and for beam profile monitoring (*,**). In addition, both laboratories are developing and testing innovative nano-fabricated wire-scanners capable of providing sub-micrometer resolution and being quasi non-destructive to the beam. Nano-fabricated wire-scanners with a free-standing design (***) and a sub-micrometer resolution (****) has been already successfully tested. In the present work, innovative nano-fabricated wire-scanners joining both features of a free-standing design and sub-micrometer resolution are presented. Experimental tests carried out at SwissFEL demonstrated the capability of such innovative wire-scanner solutions to resolve transverse profiles of the electron beams with a size of 400-500 nm without incurring in any resolution limit constraint and with a minimal beam perturbation. An overview on current status and results along with future developments of these nano-fabricated wire-scanners are here presented.
(*)G.L.Orlandi et al. PRAB 19, 092802 (2016).
(**)M.Veronese et al.this Conference.
(***)M.Veronese et al.NIM-A 891, 32-36, (2018)
(****)S.Borrelli et al. Comm. Phys.-Nature, 1, 52 (2018).
slides icon Slides TUBO02 [10.551 MB]  
TUBO03 Challenges in Continuous Beam Profile Monitoring for MW-Power Proton Beams -1
  • M.L. Friend
    KEK, Ibaraki, Japan
  Continuous beam profile monitoring of the high-power proton beam is essential for protection of beamline equipment, as well as for producing high-quality physics results, in fixed-target extraction beamlines. Challenges in continuous profile monitoring include degradation of materials after long-term exposure to the proton beam, as well as beam loss due to that material intercepting the beam, which can additionally cause activation of nearby equipment. An overview of various profile monitoring techniques used in high-power neutrino extraction beamlines, issues faced so far at beam powers up to several hundred kW, and some possible future profile monitoring solutions for MW-class beamlines will be shown.  
slides icon Slides TUBO03 [13.146 MB]  
TUBO04 Measuring the Beam Profile by Counting Ionization Electrons -1
  • H.S. Sandberg, W. Bertsche
    UMAN, Manchester, United Kingdom
  • D. Bodart, B. Dehning, S. Levasseur, H.S. Sandberg, G. Schneider, J.W. Storey, R. Veness
    CERN, Geneva, Switzerland
  • S.M. Gibson
    Royal Holloway, University of London, Surrey, United Kingdom
  • K. Satou
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
  The principle of non-destructive beam profile measurement with rest gas ionization electrons has remained largely unchanged since the technique was first proposed in the late 1960’s. Ionization electrons (or ions) are transported by an electrostatic field onto an imaging detector, where the spatial distribution of detected electrons is a direct measure of the transverse beam profile. The detector typically consists of one or more Micro-Channel Plates (MCP’s) to amplify the signal, followed by either a phosphor screen and camera, or pickup electrodes. A long-standing problem is the ageing of the MCP’s, which limits the accuracy of the beam profile measurement. A new technique to detect ionization electrons has been developed at CERN, which uses a hybrid pixel detector to detect single ionisation electrons. This allows the application of counting statistics to the beam profile measurement. It will be shown that a meaningful beam profile can be extracted from only 100 electrons. Results from the new instrument will be presented, which demonstrate the ability to measure the beam profile of single bunches turn-by-turn, which offers new opportunities for beam diagnostic insights.  
slides icon Slides TUBO04 [2.199 MB]