Proton Calorimetry/Meetings/2017/08/16

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Minutes for UCL Proton Calorimetry Meeting, 16th August 2017 (D107, Physics & Astronomy, UCL)


Simon Jolly, Laurent Kelleter, Jordan Silverman


  • Ran a few more simulations for build-up paper:
    • Bortfeld description fails between 200–300 MeV: at 500 MeV description is very poor (Bortfeld recommends only between 40–200 MeV).
    • At 500 MeV "entrance bump" is almost as large as the Bragg peak!
    • Electron build-up measured within the simulation by counting energy deposition attributed to electrons at each step.
    • Compare dose at depth to dose at 0.07 mm to define build-up (appropriate skin depth): approx. 2% of Bragg peak depth.
    • Hadronic build-up defined by secondary protons: several orders of magnitude larger than heavier hadrons.
    • Liquid Hydrogen simulations show much smaller entrance bump: secondary proton spectrum still retains Bragg peak (Oxygen no longer disrupting primary proton energy).
    • No secondary production of hadrons after Bragg peak in liquid Hydrogen: no neutron production so nothing gets past Bragg peak.
  • Testing PRaVDA PRIAPUS CMOS sensor:
    • Flashed single scintillator sheets with LED and imaged light with PRIAPUS.
    • Checked different scintillator thicknesses (3 and 10 mm) and different LED voltages.
    • Checked spacing between sensor and scintillator: need to keep scintillator as close to sensor as possible without touching it! Minimum distance tried was 2 mm.
    • Beam test at Birmingham Wednesday 23rd August.


  • Helping Dan Walker to update notes for experimental runs.
  • Running through Geant4 tutorials using Eclipse SSH plugin (now built-in to Eclipse C++ version): will write up some notes on editing code with Eclipse via SSH.
  • Will check through background Wiki pages to make sure they're complete.
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