Oct 5, 2017 Calorimeter

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Video Conferencing Information

Meeting Time: 11:00 a.m.

  1. To join via a Web Browser, go to the page [1] https://bluejeans.com/907185247.
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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

  1. Check in the code, including scripts, that is used for recent calibrations into git (BCAL: Mark)
  2. Andrei's time calibration code.
  3. Add Fcal dead channels into the MC
  4. Mark: Report back on study of eta with in FCAL
  5. Mark: Add monitoring plots for charged particle clusterizer
  6. From Mike's work: -cos(phi) type dependence in the data and a phi dependence at the downstream end of the bcal

References

  1. FCAL HDFCAL log book
  2. BCAL HDBCAL log book

Tentative Agenda

  1. Announcements
  2. Action Items
  3. FCAL Update
    • Run preparations
    • Other updates
  4. BCAL update
  5. Calibrations
  6. Reconstruction and Simulation
  7. NIM articles
  8. Any other business

Minutes

Attendees: Christine, George (Athens), Elton, Mark, Collin (JLab), Matt (Indiana), Will (CMU), Andrei, Zisis (Regina)

  1. Announcements:
    1. reminder about analysis talks at collaboration meeting and DNP talks later in the month.
    2. Matt will give the FCAL talk and Mark the BCAL one at the collaboration meeting.
  2. Action Items:
    1. No report.
    2. Andrei asked folks to check out and test his time calibration code, to see how it affects physics analyses. It was checked in as per instructions by Sean, on a separate branch with standalone db. The code was compiled versus an earlier version of simrecon. Andrei did the calibration on 2016 data but can repeat it for 2017 data.
    3. Matt has the files generated by his student and will put the info in ccdb soon.
    4. Mark reported that data is broader than MC. He looked at 2016 and 2017 LI data: slight differences, nothing striking. Statistics are limited.
    5. Mark has not started yet on this. He is thinking to change the way showers are reported for charged clusters, perhaps by projecting to the BCAL's inner surface. The matching efficiency is 1-2% lower with new clusterizer.
    6. Mark believes this is a calibration issue. If Mike asks he can recalibrate the 2016 data. Note that the data analysis uses channel-by-channel numbers whereas the MC has a single no for all channels in each layer.
  3. FCAL Update
    • A priority is to work on the gain balance and correct the timing offsets. IU is considering to modify the reconstruction to use a better timing technique. Also, a neural net algorithm for photon-hadron separation is being investigated. This would require changing the REST format to include extra info (classifier) about the shower.
    • Run preparations: Jon and Collin will work in bringing the FCAL up. Elton added that its crates are already up and running for trigger studies by Sasha.
    • Other updates
  4. BCAL update
    • Run preparations: Elton brought up the biases and LV system last Tuesday. The latter failed on 3 LV modules. Something similar happened last year after the long down. The modules were sent to Wiener and it turned out it was hardware settings that were changed and which caused trips. Chris and Nick have the tools to check and reset these. These are not currently handled by EPICs but Hovannes is looking into this. The cause is not known but at least we have a fix. Ahmed and Tegan will bring the LED system up and look at all channels especially the iffy ones from last spring.
    • Layer efficiency studies (Elton): This will be brought up during the collaboration meeting. ver 21 of clusterizer is recording more matched tracks than ver 19 but showers are broader. This is probably an artificial problem in how showers are added. Will asked how the matching efficiency is calculated. Mark and Elton said that the code is quite complex and that they are talking to Paul about it. This effect might be due to a strange definition of this efficiency. Elton suggested looking at 2D plots of efficiency versus momentum subject to a 1 GeV cut to eliminate photons that might contaminate the efficiency definition.
    • Other updates: none
  5. Calibrations
    • 2017-01 recon ver02 plans: The 2016 data will need to be recalibrated as folks (such as Mike for SDMEs) needs that data. The decision will be likely formalized at the collaboration meeting.
    • Exclusive pi0 (Tegan): Andrei reported that Tegan is making progress, converging to the pi0 mass after about 10 iterations and width has improved to 9 MeV, although Will got 7 MeV. Will mentioned that after starting with flat gain coefficient his method took 8-10 iterations. Tegan has tried both flat and the actual channel-by-channel coefficients.
  6. Reconstruction and Simulation
    • BCAL charged particle clusterizer (Will): Added data member (Q=0 neutral, Q=1 charged) to master branch. It is in the shower factory and can be added to the REST file if people have a specific use for this. This will be discussed at the collaboration meeting.
    • BCAL neutron clusterizer (Andrei): Andrei showed plots of the standalone, fine-grained simulations that he and Irina have been carrying out in determining ways to discriminate neutrons from photons. This MC includes the detailed BCAL matrix geometry as well as waveforms to extract FADC times. Key variables are the time structure and multiplicity of the showers. Hit distributions were looked at as well. In the future TOF for the low momentum particles can be added and this will help. The selection criteria used for neutron-photon separation were the same for all momenta and angles. One criterion included 1 cell exceeding the 2.5 MeV threshold. Efficiencies and leakages for both neutrons and photons were shown. Things look good overall with efficiencies >90% in the forward direction. This work does not include any reconstruction: it uses particle guns. Also, different shower shapes (em vs hadron) are not taken into account nor are things as a function of depth (layer). Next is to look at the data.
    • A follow-up for the pi0 pi0 final state (George): Previously, differences between MC and data were reported. It was suggested to check how the cuts affect these. George looked at the 2016 and 2017 LI data. After the MM cut there are larger deviations between MC and data. George noted that bggen does not contain f1 or f2, etc. Cuts tested are unused energy, baryon cut, CL. Next, George will vary the cut values to continue the study. Elton remarked that the currently low MC stats are limiting conclusions. The upcoming 2017 large simulation will help in this regard. Christina asked what is the best way to get the signal into the MC stream. Matt replied that this should be done by hand (eg genr8) for now, with a reasonable guess on the cross-section, as such cross sections are not measured. The Collabration is considering a larger effort in the future to replace bggen generators with proper angular distributions and t dependence.
  7. NIM articles: Elton reported that Mark and Beni have given comments on the BCAL NIM and Eugene is going through it now. The discrepancy between the pi0 and eta extracted constant term in the energy resolution is now understood as depending on the sampled used. A new plots has been added to explain this. This constant term rises at small angles. Christina asked if it depends on layer thickness and Elton answered that that effect is in the MC.
  8. Any other business: none
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