Jan 23, 2020 Calorimeter

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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


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

Goals for Calorimetry Group

  1. Determine preliminary photon reconstruction efficiencies as a function of E, phi and theta in data and simulation with a point-to-point precision of at least 5%.
  2. Measure systematics of pi0/eta mass calibration as a function of detector position to a precision of at east 5 MeV.
  3. Demonstrate agreement of photon reconstruction efficiency and resolution between data and simulation as a function of E, phi and theta to within 5%.

Action Items

  1. Check that beam displacements have been incorporated into geant4 simulations (Elton) Beam displacements need to be incorporated into the event generators. </strike>
  2. Systematically fix labels on FCAL crates (Colin/Elton)
  3. Ship back bases to IU that fail repair (Colin)
  4. Order spare FCAL electronics (Elton) Spares have been ordered, although they have not been received yet.
  5. Complete Calorimeter work packages

Long term items

Tentative Agenda

  1. Announcements
  2. Run Updates
    1. FCAL
    2. BCAL
  3. Calibrations
  4. Monitoring
  5. Reconstruction
  6. Efficiencies
  7. Simulations
  8. NIM articles
  9. Any other business



  1. Announcements
    • Town Hall meeting this afternoon with Deputy Director for Science Programs J. Steve Binkley, Associate Director for Nuclear Physics of the Office of Science Timothy Hallman and Brookhaven National Laboratory Director Doon Gibbs to speak on the recent DOE site selection decision for a future Electron-Ion Collider.
    • Collaboration Meeting February 13-15, 2020.
    • Jon volunteered to give the update but we will need to help in collecting material since he will away immediately before the collaboration meeting.
  2. Action Items
    • Mark: On pull asymmetries. Any asymmetries in the MC x-position pulls point to a problem if the MC is symmetric and needs to be pursued.
  3. Run Updates
    1. FCAL
      • Bases have been replaced that failed during the down. Rate is down to about 4/week. We only have a few spares, but Chris and Nick should be able to keep up by repairing about 5/week. About 20-25 bases will be shipped back to IU for Paul Smith to investigate.
    2. BCAL
      • Mark: Monitoring plots this morning showed timing shifts of about 20 ns. Possibly due to changes in firmware? Sean: Offsets are ok and red line on monitoring plot shows nominal position, which is consistent with last fall. (See link to histograms below).
  4. Calibrations
    1. Toy Monte Carlo to study non-linearities (Elton)
      • Elton has written a toy MC to help understand non-linearities and how to correct for them. Quite a bit of discussion and information is just now being digested. From the conclusion slide
      • For non-linearity correction fits, fix the energy of low-energy photon (E2)
      • End-points are affected by resolution effects
      • Need to optimize the use of symmetric photons to determined non-linearity at low energies and matching to distribution at higher energies.
      • Mark: a corollary to this study is that if the distribution of pi0_measured/pi0_true is flat, we cannot infer that there are no non-linearities.
    2. Nonlinearity_correction_study_update (karthik)
      • Karthik has investigated the energy dependence of pi0_measured/pi0_true taking E2=constant (instead of integrating over it), and also evaluated the E2 dependence by taking E1 constant at high energy. The preliminary conclusion is that there is very little non-linearity at high energy, but not so at low energy.
      • Elton: Plot the results of the symmetry non-linearity study on top of these new asymmetric non-linearity plots for comparison.
      • We will continue to pursue these new ideas offline.
    3. Online monitoring from run 71517 showing good timing alignment
      • See BCAL online. It appears the BCAL and FCAL shifts are expected and consistent with the red line that indicates nominal position.
      • Jon: More concerning is the spike at the beginning of the window. Sean: Likely due to noise hits and seems to be due to the new firmware. Mark: Might be useful to check raw mode files to investigate the spike.
      • Sean: We need to check that the BCAL 4 ns timing shifts are absent with the new firmware. Mark is working on this.
  5. Monitoring
  6. Reconstruction
  7. Efficiencies
  8. Simulations
  9. NIM articles
  10. Any other business