SoLID Ecal Weekly 20230420

Discussion on Tracking

• Presentation by Xinzhan
  • For GEM alignment, chi2 minimization yields incorrect result. There are many existing publications on how to best fit the alignment, trying out the algorithm. **Currently, spending time on VMM test + SoLID beamtest (50/50)

Discussion on Simulation

• Presentation by Ye
  • looked at more on LASPD timing, seems to be earlier than ShowerSum by about 12ns, Jixie explained that this is already shifted at the software level when doing the peak-finding, Jixie will pass on information on how to read this timing shift from the database, and then Ye can plot the timing peak with the shift added (by hand) to confirm that it’s truly corrected.
  • 5uA run 4680 already has 10.2MHz in LASPD and higher than both J/psi and SIDIS expected rate.
  • photon rejection: 2:1 right now from LASPD, 5:1 from simulation. Is the sample “clean”? lot of work to do:
    • account for charged pion, confirm charged pion rate with data, subtract from data or add in simulation
    • minor: should cut out preshower single-MIP peak for the charged pions.
    • check LASPD timing (see above)

Discussion on Analysis

• Jixie: pulse deconvolution works for ECal but not other detectors because the pulse shape are different → start writing a note summarizing, along with a general approach of how to set up the algorithm for “new” detectors
• Tim: level-1 tree has only one track saved, is that correct? Jixie: that’s the best track candidate from the level-0 tree.

General discussions

• Jianping: Chao /Zhiwen is working on software (end-to-end) for SoLID, starting from ECal (both sim and data).
• LASPD timing readout discussion with Alexandre: The 250MHz FADC we have, when implementing the factory firmware, can reach about 150ps timing resolution for the peak edge. However, adding this to the 150ps of the LASPD and PMT itself means we are getting 240ps.
  • We need higher sampling FADCs
  • Alexandre: Hall C has implemented FADC firmware in their analyzer code for edge finding (timing), Jixie will follow up and see if we can integrate to study LASPD timing.
  • MRPC work: can’t buy >5GHz FADC using THU fund (and send it to China)