MOLLER Pion Background Meeting Tuesday, October 10, 2017 4:00pm EST

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Previous Meeting: MOLLER_Pion_Background_Meeting_Tuesday,_September_26,_2017_4:00pm_EST

Meeting Information

BlueJeans Call Information


Phone Number: 1-888-240-2560

Meeting ID: 624029893


  • Director's Review Questions (Completed by end of summer 2017):
    • Summer just about complete, new deadline?
      • mu+ + mu- background?
      • beam dump back scattering background?
  • Wouter: General simulation updates.
  • Scott: Lead wall thickness determination.
  • Nevin: Pion Calorimeter Studies
  • Any new business?


Attendees: David, Kurtis, Paul S., Neven, Yufa (LATech, Neven's student), Scott, Dustin

Not Attending: Seamus (traveling), Wouter (Mainz)

Scribe: Kurtis

  • David: Update here in at WM, Scott is still working on some remoll compile issues. Just about worked out. Might be able to have some initial results by next meeting.
  • David: General Director's Review Questions status:
    • mu+ + mu-: Still in progress, on Wouter's todo list.
    • Beam dump background: David, hoping to have Cip's PREX beam dump geometry ported over to remoll in the near term.
  • Neven: FLUKA simulations results
    • Rakitha imported remoll geometry into FLUKA. Almost completely ported over geometry except for magnetic fields and Hall A beam dump.
    • Looking at rates predicted from FLUKA, comparing to measured rates and previously determined remoll rates.
      • Full rates from in nominal theta, phi, and momentum acceptance. Really need magnetic field to determine true momentum acceptance of electrons and pions.
    • Finding factor of 10 decrease in the pion/electron ratio. Meaning we could have a low rate of pions in our acceptance.
    • Neven believes that FLUKA does have Moller and other electromagnetic process implemented.
    • David, really need to confirm these results with Geant.
    • Neven, need to perform additional FLUKA simulations to increase simulations statistics. Next time, should have a better understanding of the results with better statistics.
    • David, can you turn on or off separate process in FLUKA? Neven, Yes at some level. Might not be able to determine the physics processes that generate the particle that reach the final acceptance. Would have to rerun simulation with certain physics processes turned off. David, important to realize it can be difficult to understand simulations with certain process turned off. Neven, just need to confirm in the future.
    • Neven, many publications seems to show good agreement (5-10% level) between Geant and FLUKA for other experiments.
    • Neven, FLUKA should also be able to answer the muon background question as well.
    • Neven, estimates muon contamination at about 1%.
    • David, Agrees that FLUKA and Geant simulation should be developed together and compared along the way.
    • Neven, The interpretation of any such comparison could be difficult. Should have better results, with improved statistics, by our next meeting time in two weeks.
    • Neven, looking for an acceptance function for the detector rings, so that he wouldn't have to include the magnetic field in FLUKA.
    • Neven, starting to look at the optical response of the Cerenkov (pion) counter. Future results soon to come.
  • David, Thanks Dustin for passing on the Showermax geometry. Scott will modify the geometry he currently has in the pion branch.