SoLID Ecal Weekly 20231005

Update on MIP study

Ye's slides: [1]

• To clean up the MIP data sample:
  • Baseline shift correction
  • Gain shift correction (based on MIP height)
  • Fix 40ns as the integral TW in the decoder
  • SC_A & SC_D trigger efficiency is very low at ~3%, in order to get pion dominant samples, we need to apply Shower_{i}/ShowerSum>0.8+ 200 ADC<preshower<500 ADC cuts.
  • The conclusion is that the MIP peaks we looked at are indeed MIP peaks, there is no confusion about that.

Pion rejection study

Mike's slides:

• comments from the meeting:
  • suggest including "slope cut" values that corresponds to 1 GeV (or 0.7 GeV??) electrons, lowest momentum needed according to preCDR. Also need to add the electron momentum that corresponds to the Cherenkov threshold for pions, since above this value the Cherenkov will stop working and we have only ECal for e/pi separation.
  • get the correct bg-mixing method from Zhiwen
  • for data, add calibration of Sh vs. PS using MIP positions and the simulated Edep of MIP.
  • use simulation to study whether there are low-energy electrons in the data pion sample. The plot of "SH+PS sum" suggests there are, because it looks like a small MIP peak sitting on top of a larger low-energy tail.
  • There was some discussions about whether we need to do PID study of Cherenkov. Answer currently is no because Cherenkov was already tested before.

Discussions

• NPS: Alexandre said NPS calorimeter isusing 10-stage HV dividers but the last 2 stages are bypassed to avoid high anode current. The base is active with a x12 preamp. The active base is a concern for the long running period of NPS given the radiation.
• Which PMT is being used for NPS?