Hall A » SBS experiments » SBS-analysis » BBCal_calibration

• Check the status of BBCAL energy calibration and time alignment using pass2 QA data for SBS8 LH2 dataset. Root files are located at: /volatile/halla/sbs/sbs-gmn/GMN_REPLAYS/pass2/QA_FINAL/SBS8/LH2

Attached are BBCAL QA plots (qa_pass2_lh2_sbs8.pdf). I have chosen a couple of runs from all the different field settings.

• These data were replayed with very tight tmax cut (+/- 10ns) and the updated clustering algorithm.
• Cuts:
  • basic good electron cuts
  • |W2-0.88|<0.4
  • NO HCAL cut

• Combined resolution (5.6%) looks reasonable.
• E/p peak position however is slightly shifted (~0.98).
• Time alignment look very good across all the field settings. TH-BBCAL coin time peaks are the ones we should look at. HCAL-BBCAL coin time peaks show slight non-uniformity when plotted as a function of run numbers.

• Energy recalibration will be necessary. Planning to do after DNP. Lemme know if there is a reason to rush.
• Realigning time isn’t necessary but I may choose to align time per field settings. But definitely not before DNP.

• I have already recalibrated energy for SBS8 - SBS50p dataset using these runs. Attached are the diagnostic plots (qa-newclalgo-10ns-sbs8-sbs50p_prepass2_bbcal_eng_calib_elcut.pdf). Final results look great! 5.4% resolution with E/p peak position at 1. With the old clustering algorithm and no tmax cut we achieved 5.5% resolution. So, I can reconfirm that applying +/- 10ns tmax cut is the way to go.

Previous energy and time calibration diagnostic plots can be found here: https://sbs.jlab.org/cgi-bin/DocDB/private/ShowDocument?docid=367 https://sbs.jlab.org/cgi-bin/DocDB/private/ShowDocument?docid=406

As always, any feedback will be appreciated.