BCAL Reconstruction Meeting 2015-09-03

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Video Conferencing Information

Meeting Time: 11:15 a.m. EDT

  1. To join via a Web Browser, go to the page [1] https://bluejeans.com/907185247.
  2. To join via Polycom room system go to the IP Address: (bjn.vc) and enter the meeting ID: 907185247.
  3. To join via phone, use one of the following numbers and the Conference ID: 907185247.
    • US or Canada: +1 408 740 7256 or
    • US or Canada: +1 888 240 2560
  4. Upon connection all microphones are automatically muted. To unmute your mike on a Polycom or equivalent unit, enter *4. Unmuting on a computer is trivial as there is a microphone button than can be clicked.
  5. More information on connecting to bluejeans is available.

Participant Direct Lines

  • JLab Phone: in CC F326 is 757-269-6460 (usual room)
  • JLab Phone in CC L207 is 757-269-7084
  • Phone in the Regina Video-conference Suite is 306-585-4204


  1. BCAL Reconstruction Issues
  2. BCAL Reconstruction Algorithms
  3. Will's reconstructed energy info

Action Items

  1. F250 discussion: peak value into higher level objects (Mark)
  2. Make MC plots that show E vs Egen and resolution (Tegan)
  3. Determine up/down gain ratios for spring data (Mark)
  4. Low priority items
    1. z-coordinate determination from up/down amplitude ratio
    2. Sampling fraction tables (Tegan, Andrei)
    3. Code Cleanup


  1. Announcements
  2. Action Items
  3. Commissioning Efforts
    1. BCAL - Effective Speed of Light (George)
    2. Time-walk corrections (Noemi)
    3. Layer efficiencies (Ahmed)
    4. Muon decays (Elton)
  4. Reconstruction
    1. Single-energy hits (Will M.)
    2. eta reconstruction (Tegan)
  5. Simulations
    1. CPPsim (Tegan)
  6. Any other business


Attendees: Mark, Simon, Elton (JLab), Curtis, Will M. (CMU), George (Athens), Tegan, Noemi, Ahmed, Zisis (Regina)’’

  1. Announcements
    1. Magnet & accelerator issues: no run schedule yet for December, maybe standby shifts. Runs in the spring possibly extended by 2 weeks if we get no beam in December.
  2. Action Items:
    1. F250 peak value: Mike will do this (he is currently away).
    2. E vs Egen (Tegan): will report at next meeting.
    3. up/down gain ratios (Mark): made plugin that extracts these now, most recent runs included this plugin and Mike’s TDC plugin, some runs failed. Remove as action to agenda.
  3. Commissioning Efforts
    1. BCAL - Effective Speed of Light (George).
    2. The BCAL DGeometry file is ready, missing methods filled in but values are not returned properly; David sent info on how to implement a fix.
    3. Plots based on last week’s comments.
      1. z_track calculated at beginning of each layer vs middle of layer. Commissioning runs 3127 and 3136 have problems so they are only used for reference. Run 3179 is good, each layer has diff v_eff but within a layer it is stable. New Comics plots have no cuts on and are close in v_eff to the old 20 cm cut plot (left panel in George's slides), but are now very stable and without requiring a cut. Using less angular tracks (z coordinate cut) suggestion: results are strange, broad range of v_eff values. Elton: What do the linear fits look like? With cut more scatter, but no curvature. Comics should not change (independent of z, unlike beam), so there is something really strange here. Mark: make a fit from comics, 100-200cm. Pick an outlier and look at the fits.
      2. Throw away low-momentum tracks (pmag>0.7 GeV/c). 3179 layers 1, 2, 3 no change, 4 has oscillation: this cuts make things worse. No entries in mag - null entries because Run 3138 has B=0 so no momentum can be calculated.
      3. Elton: | log entry 3350054: Difference between beam and comics data, layer dependence seen more strongly in beam data. Model Simulation done: difference because of showers (see figure in this entry). Graph saturation (only layer 4 shown here) is due to only partial shower detected. This simple model shows variation should be expected vs layer. We should extend this by simulation and possible have a non-linear model. For linear model that we have Comics & Layer 1 numbers should be used in ccdb. Ultimate goal is to get time of arrival as accurately as we can.
    4. Time-walk corrections (Noemi): no report.
    5. Layer efficiencies (Ahmed): working on draft report, available soon. Tried cutting low energy hits showing in Mod 7 only, does not affect layer efficiency. Average point energy in Mod 7 is lower (0.038) than Mod 8 (0.05) by 25%. Negative hits are being excluded. Mark: emulation is not fixed yet, so Mod 8 does a better job. Average point energy might be sensitive to distribution. Ahmed will produce plots showing the distributions. Mark: look at clusters and compare to points; low E points may not have a big effect in clusters. So far no explanation for Mod 7 vs Mod 8 efficiency difference. 1 MeV cut (20 cuts). Mark: Negative energy are only one group of problematic hits; sometimes too much pedestal is subtracted. Put cut on time (in monitoring plugin), so to eliminate late hits (see Mike’s email: “The fix is to require that (peak height - per event pedestal) / 2 > threshold. This essentially doubles the threshold to have a hit, which might not be an acceptable solution.”) After this cut there should be no negative energy events even without negative energy cuts (this is a more correct way to do it).
    6. Muon decays (Elton/Will M): Will M. is running over data now implemented Mike’s cut, decays seen in Mod 8 but not Mod 7, will send plots soon. Electron energy in Mod 8 is smaller than expected. Report in two weeks.
  4. Reconstruction
    1. Single-energy hits (Will M.): can be removed from agenda. Code has been updated. Single-ended hits should be included & code is checked in? Will M will check.
    2. eta reconstruction (Tegan)
  5. Simulations
    1. CPPsim (Tegan)
    2. Cosmics runs and simulations for B-field: statistics marginal.
  6. Any other business: Elton will be away next week, Zisis will run the meeting.