Jan 11, 2018 Calorimeter

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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

  1. Check in the code, including scripts, that is used for recent calibrations into git (BCAL: Mark)
  2. Add monitoring plots for charged particle clusterizer [Will to suggest plots and collaborate with Mark]
  3. Checks of MC calibrations for BCAL. Timing (Sean and Mark), non-linearities (Will)

Complete after new launch

  1. Report back on study of eta with in FCAL [Mark]
  2. 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
    1. Run preparations
      1. FCAL Health
    2. Other updates
  4. BCAL update
    1. Run preparations
    2. Other updates
  5. Calibrations
  6. Reconstruction and Simulation
  7. NIM articles
  8. Any other business

Minutes

Attendees: Elton, Colin, Mark (JLab); Matt (IU); George, Christina (Athens); Andrei, Zisis, Ahmed (UofR); Sean (FSU); Cristiano (MIT).

  1. Announcements
    • BCAL paper submitted to NIM. It is also on the archive at https://arxiv.org/abs/1801.03088
    • Accelerator is running a couple of days ahead of schedule. Shifts are being taken by local volunteers.
  2. Action Items
  3. FCAL Update
    1. Run preparations
      • FCAL Health
      • On Tuesday, all bases were on and at voltage. There are now a few bases that are sagging.
      • LED data shows 2 dead channels. The bases and pmts were replaced. Matt: The only pmt failure is due to loosing vacuum, which can be seen by visual inspection when the copper-colored cathode disappears.Colin: At least one pmt had lost the photocathode.
      • There was a discussion of "hot channels" that could affect trigger performance. Colin will check with Sasha to get a list.
      • Discussed a threshold scan for the FCAL to see if the readout threshold can be lowered. Time to do this test was scheduled for late in the afternoon. [Note added: Colin took the data last night]
      • The pedestals needed to be set before the scan. [Note added: Serguei set the pedestals for all FADCs (except start and TOF) at noon].
      • Comment: We should setup a systematic time to reset pedestals (e.g. on maintenance days).
      • LED script to cycle through FCAL configurations (3 colors and 2 voltages) is operational (Mark).
    2. Other updates
      • Monitoring plots for FCAL (pi0 peak). Colin will work with Thomas to make the existing plot more useful.
  4. BCAL update
    1. Run preparations
      • BCAL has been setup with the same parameters as last spring: chiller at 5 deg C, 1.4 V overbias, LED configurations cycling at 10 Hz.
      • Zisis: It would be useful to take some dedicated LED data during the maintenance day for dedicated checks.
      • Zisis: What is done about the poor quality channels from last spring. Elton: The main problem was fixed (loose cable connection). The others had some shifts in their gain by a few percent sometime during the run. We haven't done anything special, but we should check on them when the data come.
    2. Other updates
  5. Calibrations
  6. Reconstruction and Simulation
    1. FCAL Energy Resolution Study (Cristiano Fanelli)
      • Cristiano showed pi0 MC and data and showed that the distributions were consistent with the expectations from energy and angular resolution.
      • Matt: The angular resolution is taken from MC and could contribute significant systematics to the energy resolution extracted at large energies
      • Elton: The distributions are compared to 5.7%/sqrt(E) + 3.5%. Where did these values come from? Matt: The schocastic term is taken from RadPhi adjusted for increased light collection in the present FCAL. The floor term is a conservative estimate for contributions from calibration accuracy.
      • Elton: It appears that the flat behavior that was seen in the Fcal energy resolution may be explained by the angular resolution term. Colin: It is also the case that the pi0 peaks extracted for high energy may suffer from poor fits to peak and background.
      • Notes added by Zisis (Elton had to go to his shift): A discussion took place on whether Cristiano’s analysis should be attempted on inclusive pi0. Matt stated that CF’s method is the best way to measure the width (background manageable) . The old FCAL plots on slide 6 were a decent early attempt, but CF’s method gives more robust results. Christina asked about the opening angle between two photons at 4 GeV and Matt said that it is 2.5 deg; Cristiano added that his cuts that the two photons have angles greater than 2 deg and be apart more than 12 cm eliminates extreme opening angle events.
  7. NIM articles
  8. Any other business