Mar 22, 2018 Calorimeter
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Contents
Video Conferencing Information
Meeting Time: 11:00 a.m.
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Participant Direct Lines
- JLab Phone in CC L207 is 757-269-7084 (usual room)
- JLab Phone: in CC F326 is 757-269-6460
- Phone in the Regina Video-conference Suite is 306-585-4204
- Athens Phone: in Christina's office is 011-30-210-727-6947
Action Items
-
Decide on approach to FCAL timing calibration and proceed with it (Matt, Mark, Colin)High level timing cut on Fcal of < 2.5 ns was eliminating matches in the Fcal due to some 4 ns crate offsets. Relaxing the cut to < 6.5 ns prevents this problem and is used as a temporary fix. -
Checks of MC calibrations for BCAL. Timing (Sean and Mark)See reports below. -
Determine what fraction of pi0's skims from 2018 data are needed for calibration work.See notes below.
Complete after new launch
- Report back on study of eta with in FCAL [Mark]
- From Mike's work: -cos(phi) type dependence in the data and a phi dependence at the downstream end of the bcal
References
- FCAL HDFCAL log book
- BCAL HDBCAL log book
Tentative Agenda
- Announcements
- Action Items
- FCAL Update
- Run related
- Other updates
- BCAL update
- Run related
- Other updates
- Calibrations
- Reconstruction and Simulation
- BCAL timing resolution (Mark)
- Track matched hit timing in MC: Proton in SC proton in BCAL (Sean)
- NIM articles
- BCAL paper has been resubmitted to NIM
- Any other business
Minutes
Attending: Elton, Mark, Colin (JLab); Will, Curtis (CMU); Zisis, Ahmed (UofR); Matt (IU); George (Athens); Tolga, Rupesh (FIU); Sean (FSU)
- Announcements
- Action Items
- All immediate action items addressed.
- FCAL Update
- Run related
- Ready to go for the weekend. Past two weeks only 2 bases have lost voltage. Could the low fatality rate be due to no beam in the hall?
- Replaced about 10-20 bases per week during the run, but criteria for replacement was very aggressive compared to previous periods (require a single drop of HV, not complete failure).
- Elton:
- Other updates
- Run related
- BCAL update
- Cosmic runs have been taken 41759 (16 hours, 38 M events), 41730 (49 hours, 115 M events), 41675 (67 hours, 180 M events) with the production cosmic-ray trigger. Zisis will check the files with Tegan and prepare for Colleen to work with them during the summer.
- Run related
- Other updates
- Calibrations
- Statistics needed for pi0 calibrations
- Will: Collected information based on calibration experience in 2017. Approximately 70M pi0s needed to complete calibration up to layer 3 with an energy cut of 0.5 GeV. For the non-linear correction one requires symmetric decays and therefore requires about x5 more statistics to determine the correction up to about 2.5 GeV. Will used about 10-20 runs in 2017 for the calibrations and about >50 runs for the non-linear corrections.
- Sean: To date we have taken about 300 runs and skimmed about half. So this should be plenty of data for this part of the run. Proposal: skim about 10-25% of the upcoming data and see how the calibration works on this sample. Mark: Eventually all files should be skimmed for full reconstruction.
- Sean's Calibration list
- Mark has kept up with BCAL low level calibrations for 2018.
- Attenuation length, Gain ratio and z position calibration constants are taken from 2017. They will be updated with the upcoming launch data.
- Fcal: Colin has completed pedestal, gains and non-linear corrections using the skimmed data (about 2/3 of the data is processed). He will update Sean's table with the range of run numbers.
- Statistics needed for pi0 calibrations
- Reconstruction and Simulation
- BCAL timing resolution (Mark)
- Analyzed 2017 data and compared to recent bggen MC data produced by Thomas
- Current MC simulation uses a constant smearing of sigma=220 ps.
- Summary: neutrals match fairly well assuming an energy dependent sigma = 0.16ps /sqrt(E) + 0.1 ns
- Measured charged track resolutions are similar in structure to neutrals. However, the MC generates resolutions of about 400 ps independent of energy with no additional smearing.
- Mark showed examples of fits at 1 GeV
- Proposal: change MC to use the sigma = 0.16ps /sqrt(E) + 0.1 ns in mcsmear. This will match the neutrals and the charged are roughly unaffected because the base level is so high to start.
- Sean: Look at particular reactions to understand resolution. Elton: Perhaps investigating timing of neutron showers could shed some light on the timing distribution of hits in MC.
- Track matched hit timing in MC: Proton in SC proton in BCAL (Sean)
- BCAL timing resolution (Mark)
- NIM articles
- BCAL paper has been resubmitted to NIM
- Any other business