Proton Calorimetry/Meetings/2016/11/09

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Minutes for UCL Proton Calorimetry Meeting, 9th November 2016 (D17, Physics & Astronomy, UCL)


Simon Jolly, Ruben Saakyan, Laurent Kelleter, Andreas Christou, Matthieu Hentz, Adam Knoetze, Anastasia Basharina-Freshville (Phone)


  • Looking at improving fitting of Caen ADC spectrum.
  • Possible advantages of Vavilov distribution over Landau: much more complex to calculate however! RS suspects Landau will be more appropriate...
  • Continuing to look at spectrum fits for lower energy histograms.
  • Not sure which input datasets being used for fits: need to start with better distributions. Check runs listed in Proton_Calorimetry/Experimental_Runs/2016/Aug2-3.
  • Looking to use more efficient methods of numerical integration to speed up fitting in ROOT.


  • Working with the Caen detector emulator.
  • Producing waveforms! Used standard Caen waveforms, including overlapping multiple waveforms.
  • Now needs to start using actual data to reproduce calorimeter spectrum.
  • RS and ABF suggested to start using real spectrum, with individual waveform to come later.
  • Detector emulator also allows input of time distribution: to come later...
  • Also checked whether Python script to do conversion from scope binary data is working by reconstructing spectrum and comparing to Caen ADC spectrum.
  • RS suggested comparing scope waveforms to Caen


  • Modified protonPB simulation to use 60MeV proton beam: results match with Clatterbridge data.
  • Tried to move detector and source to match positions in Roisin's simulations: no particles interacting with detector.
  • SJ suggested going back to original simulation and making small changes to pin down source of error.


  • Successfully upgraded Geant4 simulations from SLC5 to SL6 (with Lawrence Deacon's help)!
  • ABF suggests checking output of simulations and making sure they match.
  • Now looking at changing detector visualisation from DAWN to better visualise detector geometry.
  • SJ suggested contacting Tony Price at Birmingham as he has sophisticated visualisation for PRaVDA proton CT simulations.


  • Detector setup ready for next Clatterbridge trip.
  • Still needs to look into transporting equipment to Clatterbridge and arranging accommodation.
  • RS suggested taking 50 Ohm splitter to directly compare Caen digitiser and scope data for a few runs.
  • SJ will check working hours on second day.


  • Responses from Liviu Penescu at MedAustron regarding possible experimental visit:
    • It is possible to get 2 shifts for measurements; for more than this, it will be quite difficult, due to busy schedule at this time.
    • The room to use will be the one for "non-clinical research"; that means that the setup can be done earlier.
    • The shifts can also be during the week-nights (22h00 to 06h00), not only during weekends (but this does not increase the chances of getting more than 2 shifts before end of February, because the total pool of shifts is the same...).
  • The main remaining concern at MedAustron is the intensity. Even though there are several possibilities to reduce the beam intensity delivered per second at the isocenter, all of these would require further beam commissioning shifts aimed at this, which is not possible in the needed timeframe. Therefore there are two remaining solutions:
    • To reduce the particle number by using collimators. There again, MedAustron have the constraint that the beam at the isocenter is of only 4mm (more information from Liviu on sizes and locations of collimators to follow).
    • To install the calorimeter off-centered, in order to use only the beam "halo".
  • SJ will find out exact dates: February better than January for RS (ABF: not 18th Feb!).
  • Discussion with Ros Perrin at PSI regarding UCL scintillator in LuCa lung phantom to image dose deposition for tumour motion:
    • We have cylindrical offcuts we can provide.
    • Waiting for Ros to schedule telecon with Tony Lomax: once arranged will ask about beam time.
    • PSI have better current control than other centres so would be able to provide lower beam current for our detectors.
    • Laurent interested in helping with the dose reconstruction: also involves fitting to quenched Bragg curve.
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