SoLID Ecal Weekly 20230831

Update on GEM

• Xinzhan's slides on GEM efficiency correction: [1]
• suggestions: for gain matching, GEM3 both x and y can use some matching (scale up the blue so the lower end align with the red)

Update on rate study

• Ye's slides: slides.
  • The focus is to find consistency in the "horizontal scaling" of the Shower spectra and the observed MIP height and baseline shift vs. current. We compared ("MIP height" + "baseline *2") * "T_window" and "MIP integral" and found they agree with each other within error bars. Here "T_window" is the peak integral divided by height from the decoder, which for a triangular shaped pulse would represent full pulse width (end - start) divided by 2. This is why we need to multiply baseline shift by 2 * T_window because the baseline shift would affect the integral like a rectangle (not triangle).
  • In extracting T_window, found two values. This is due to slight peak mis-identification due to pileups.
  • Preshower does not show the same PMT gain shift, though its background is quite high.
  • A difference observed between Shower and Preshower is that Shower background is dominated by small pulses, while Preshower is dominated by MIP pulses.
• suggestions:
  • for MIP scaling factor, focus on using runs after the "mysterious" 20% shift; uncertainty in the scaling factor should only be from MIP fit and other similar factors, not the 20% shift of unknown origin.

Other general updates

• Mike worked on getting event/trigger statistics
• Carter continued fitting the timing resolution. Suspect position contribution is to all of T, B, C, and D. Note: C and D are both read out from beam-right only.
• Xiaochao setup overleaf for writing, see link