BLM types

  • Plastic Scintillators
    • charged particles, gammas, neutrons
    • single particle counting
    • Read out:
      • photomultiplier
        • relative small gain
      • particle counting mode
        • higher sensitivity
        • larger dynamic range: from single particles to 10**7/s
    • radiation hardness
      • low: nach 1Mrad010**4 Gy light transmission reduced by 1/e=0.37 (disadvantage)
    • dimensions
      • cylindrical rod 2cm diameter x 10 cm length (typical)
    • puls (rough!)
      • puls hight: from 200mv to 1V
      • puls length: from 20 (to 50)ns
  • Liquid Scintillators
    • scintillator material in 1liter solvent
    • charged particles, gammas, neutrons
    • single particle counting
    • puls (rough!)
      • puls hight: as Pl. Scintillator
      • puls length: 10times longer than Pl. Scintillator -> dynamic range 10times smaller than for Pl. Scintillator
    • radiation hardness
      • 10times more radiation hard than Pl. Scintillator (due to simpler compoisition of L. Scintillator)
  • Aluminium coated Electron Multiplier
    • PMT with an Aluminium cathode
    • puls
      • fast rise time
      • high dynamic range
      • much lower sensitivity than PL. Scintillator
  • PIN diode
    • 10x10mm*2 with 0.1mm depletion zone (two face-to-face mounted PIN diodes)
      • with two PIN diodes in coincidence the low energy photons are separated from the charged particles
    • single particle counting
    • low detection efficiency due to dimensions
    • commercially available
    • puls
      • Mip -> 10**4 electron-hole pairs
  • BF_3 propartional tube
    • 10mm x 500mm glas tube filled with BF_3 gas in a polyethylen housing of 200mm diameter (<-moderation of the neutrons)
    • neutrons up to 100MeV, high crss section (1kbarn)
    • Count rate limeted lower than 10*4/s <- time to recharge the central wire
  • Ionization Chamber
    • charged particles
    • signal strength gis directly the absorbed dose in Gy (definition)
    • radiation hardness very good <- innert gas
    • puls
      • signal orders of magnitude smaller than with counting mode devices
      • slow signals <- 100 mus drift time
    • read out
      • current-to-voltage or current-to-frequency converter
      • 1ms slow
  • Optcal Fiber
    • material modification by absorbed dose
    • 1ns laser puls travals with 0.66c through the fiber and is reflected by colour centers produced by particles
    • good spatial resolution
    • slow (1s) due tu use of OTDR (optical time domain reflector)
Comparison
  • all linear
  • Pl. Scintillator has highes rate and highest dynamic range
  • L. scintillator saturation at highes rate due to the slow integrating amplifier
  • Ionisation Chamber: signal strength lower by foctor 200 than the Pl. scintillator
  • PIN diode has 3 orders of magnitude lower than PL. scintillator

-- GeorgSchepers - 15 Oct 2008

This topic: Personalpages > WikiUsers > GeorgSchepers > GeorgSchepersLeftBar > MyworkPages > BeamDiagnostics > BeamLossMonitors > BLMTypes
Topic revision: 2008-10-16, GeorgSchepers
 
This site is powered by FoswikiCopyright © by the contributing authors. All material on this collaboration platform is the property of the contributing authors.
Ideas, requests, problems regarding GSI Wiki? Send feedback
Imprint (in German)
Privacy Policy (in German)