Mar 23, 2017 Calorimeter
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Contents
Video Conferencing Information
Meeting Time: 10:00 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
- Determine number of saturation/underflows that exist in the two LED bias monitoring settings (Ahmed)
- Understand the nature of the peak in the (Fcal propagated to target -RF) satellite peak of -2 ns (Adesh)
- Disable red LED string in dark room to avoid leaving it on in the future. (Adesh)
- Quantify the LED pulser sector jumps within one run (Ahmed)
References
- FCAL HDFCAL log book
- BCAL HDBCAL log book
Tentative Agenda
- Announcements
- Action Items
- Run preparations
- Activities during the down
- LED Monitoring
- FCAL update
- BCAL update
- Calibrations
- pi0 calibrations
- Timing calibrations
- Initial timing calibrations (Mark)
- Simulation of BCAL Timing by A.Semenov & I. Semenova (UofR)
- pi0 Dalitz decay: Comparing thrown and reconstructed quantities - George
- Reconstruction and Simulation
- BCAL Hadronic Efficiencies (Elton)
- BCAL charged clustering update (Will)
- NIM articles
- Any other business
Minutes
Attendees: Elton, Jon, Mark, Adesh (JLab); Sean (NW); Will (CMU); George, Christina (Athens); Andrei, Ahmed (UofR); Matt (IU)
- Announcements
- Action Items
- Adesh: The 2 ns jumps happen at low energy. Need to investigate this further
- Run preparations
- Activities during the down
- Comic data taking concluded yesterday
- Sasha is updating firmware on all crates
- Fcal would like to take random triggers to study electronic noise without beam. This will take a couple of hours.
- All data should be taken before major mechanical activity in the hall
- Expect to leave electronics on. Bcal chillers will be parked at 18 degrees.
- LED Monitoring
- Looking at spring 2017 data.
- Finds band structure (quasi quantization) of rms values. Jon: Sees bands in Fcal base voltages reported at 16 bits that are the result of averages of 10 bit numbers. Could a similar mechanism be at work.
- Plotted rms over the run vs channel number. Investigate outliers
- High rms of some channels include zero pulses for some runs. Need to find why this happens. Short runs are excluded, so we expect all channels to have entries.
- Activities during the down
- FCAL update
- Calibration (Adesh)
- Skim files almost completed for all runs. Files copied to IU
- Checking stability of constants, e.g. pedestals, over time.
- Bases (Jon)
- Base failures seem to have slowed. 2 failures in the past two weeks.
- Calibration (Adesh)
- BCAL update
- Calibrations
- pi0 calibrations
- Timing calibrations
- Initial timing calibrations (Mark)
- Low level calibrations have been completed as a base for gain calibrations.
- Repeating work that George did for spring 2016. Use Run 30895. Some differences, including moving from TGraphs to THF2 histograms, which are more easily scalable into our software.
- Fitting z (track) vs Deltat (tup - tdown). Means develop artifacts. Now use FitSlices to determine peak values of distribution vs Deltat. Use these to fit to pol2
- p0 shows a bimodal distribution with Delta z ~ 30 ns ~ 4 ns. Suspect hardware. Discussions with Ben Raydo suggest that the hardware explanation is plausible. Special firmware was developed for Hall B to avoid this problem. Depending on origin of problem, shifts can happen either on a run-by run-basis or upon power.
- Need to iterate calibration once tracking fixes are completed.
- Sean: concern that constants may not be stable over the entire spring period. Mark: Will check stability using files remaining on the gluon machines.
- Shape of residuals is similar for all channels, which suggests the systematics comes from other sources, e.g. tracking.
- Simulation of BCAL Timing by A.Semenov & I. Semenova (UofR)
- Find that resolutions are reasonably well reproduced compared to data
- Use detailed MC to check timing response in MC and compare to data
- MC: Find vU - vD ~ 0.3 cm/ns. V decreases with layer number
- Data: Find vU - vD ~ 1 cm/ns. V increases with layer number, unlike MC. Not understood why
- Checked sigma_z vs E, find ~ 1.2 cm/sqrt(E) + 3 cm, with little systematics.
- Initial timing calibrations (Mark)
- pi0 Dalitz decay: Comparing thrown and reconstructed quantities - George
- Moved from genr8 (-> geant3), 9 GeV photons, to geant4, polarized photon spectrum
- Compare gen vs reconstructed both both modes
- Central part of resolution looks like it is ~ 100 MeV, but large tails
- Matt: This should be sufficient to investigate efficiencies.
- Elton: What kinematic fitting is used? Vertex + p4 to select event sample.
- Matt: Concern that this could bias sample. Could look into Vertex + pi0 mass + zero missing energy.
- George: Investigate method to determine single photon resolution vs energy.
- Reconstruction and Simulation
- BCAL Hadronic Efficiencies (Elton)
- Not shown, refer reference for latest updates.
- BCAL charged clustering update (Will)
- Charged particle clusterizer
- Use wire-based tracks to match to cluster seed. Use axis between track projection and cluster seed. Follow this line to add points to cluster. At this point only use phi dimension; still need to investigate z dependence.
- Mark: Would be interesting to investigate the dependence of the results on the layer of the seed.
- Find improvement in finding a single shower (when a single shower is generated) with this algorithm compared to neutral clusterizer
- Still need to study various systematics, but new algorithm is an improvement over simply using the neutral clusterizer.
- Feedback is welcome. Zisis and Andrei will send comments later today.
- BCAL Hadronic Efficiencies (Elton)
- NIM articles
- Elton and Zisis discussed updates on the Bcal NIM after the meeting.
- Any other business