Proton Calorimetry/Meetings/2016/11/02

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Minutes for UCL Proton Calorimetry Meeting, 5th November 2016 (D17, Physics & Astronomy, UCL)


Simon Jolly, Ruben Saakyan, Laurent Kelleter, Andreas Christou, Matthieu Hentz, Adam Knoetze


  • Dates for next Clatterbridge run set: 24th/25th November.
  • Planning for next run:
    • Same measurements as last run but with our divider rather than Hamamatsu active divider:
      • Our divider contains no active components (transistors etc.) to linearise response of PMT: may be reason for high rate distortion.
      • Additional capacitive resistance in active divider means higher resistance for high rates.
    • Measure high rate and linearity: retake wheel measurement.
    • Record Caen ADC, Caen waveform and scope waveform.
    • Take both scintillator blocks: start with new block, try old block if we have time.
  • Check with Anastasia about potential questions for next run.


  • Converted all data from LeCroy scope format on plus1.
  • Can’t easily find peaks as all waveforms concatenated together with continuous timebase.
  • Looking at ROOT, Geant4 tutorials and detector emulator manual.
  • Will start looking at producing periodic pulses from detector emulator.
  • Aim is to produce replica of PMT output signal for proton light pulse with realistic noise variation.


  • Looking at energy deposition with proton pencil beam tutorials on PBT Wiki.
  • Comparing energy deposition in scintillator and water: seeing nice Bragg Peaks!
  • Will redo simulations using 60MeV pencil beam and check match to Clatterbridge data. Also replot with finer energy and position resolution.
  • Next step is to start integrating Clatterbridge beamline simulation and characterise the effect of adding in each component.


  • Looking at improving fitting of Caen ADC spectrum.
  • Improved quality of fit by increasing convolution number: reduces Chi2 by about half, but doubles time to produce fit.
  • Newer fit works over larger range, improving errors on fit, but results in slightly larger energy resolution.
  • Will look at other spectra before moving onto waveform data.


  • Running simulations in Geant4 of segmented calorimeter.
  • Reading out photon production for individual scintillator slices in response to single protons.
  • Seeing both Bragg Peak and effects of quenching!
  • Possible bug in Geant4: total energy deposition in scintillator + wrapping more than initial energy.
  • Will fix scintillator and wrapping thickness and add more layers for higher energy.


  • Date of next visit to Clatterbridge fixed for 24th/25th November.
  • Have heard back from Liviu Penescu at MedAustron: still waiting on possible dates to visit for experimental runs. Liviu to confirm availability of collimators and mounting.
  • Also need to arrange PSI visit: Ros Perrin/Tony Lomax lung phantom with UCL scintillator.
  • Requested that future talks uploaded to wikiData presentations directory contain some description of the data they show and include useful info in filename.
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