BCAL Reconstruction Meeting 2013-05-09

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Teleconference Time: 11:15 a.m. EDT

  • ESNET (Number is 8542553) and EVO session (GlueX Calorimetry meeting room)
  • Phone connection only upon request.
    • +1-866-740-1260 : US+Canada
    • +1-303-248-0285 : International
    • then enter participant code: 3421244# (remember the "#").
    • or www.readytalk.com (and code without the #)

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

Action Items

  1. BCAL Reconstruction Issues
  2. BCAL Reconstruction Algorithms
  3. Andrei and Irina will check their simulations in the 5-module setup to ensure that energy is not leaking out of the single module.
  4. Will will check whether the "too many clusters" issue is due to the 4th layer and whether it gets worse as theta becomes more forward.
  5. Will to look at event-by-event effects in showers/photon, etc.
  6. Regina to check 2006 beam test for this effect in the read layers.


  1. Action Items
  2. Updates
    1. Will
    2. Andrei & Irina: Shower centroid distributions
  3. Discuss and prioritize the Reconstruction Issues and produce a timetable for the work.
  4. Any other business


Attendees: David (JLab), Will Levine (CMU), Andrei, Zisis (Regina)

  1. Action Items: none
  2. Updates
    1. Andrei & Irina: Andrei presented the simulations from the single-module standalone MC, showing the energy deposition centroids. Two observations are apparent: a) as theta decreases from 90 deg, the centroid loci for the triple and quadruple layers deviated significantly from the direction of the incoming photons and b) even though the 3rd and 4th row clusters are not on the line, they belong to the event so they their energy needs to be accounted for, although they should not be used untreated to define the photon path through the layers. Other observations include the broadening of the 4th layer and the spread of the 1st layer to smaller z values. David reminded us that the field near the outer layers has a radial component. Zisis mentioned that the 2006 beam tests may not have many events in the rear layers sine the tagger energy went up only to 650 MeV.
    2. Will compared the KLOE and IU codes at 20 deg for 1GeV, and they gave 1.07 and 1.10 showers/photon. Conversions prior to the BCAL are playing a role in this exercise. Some come from the 8mm Al top plate. The reconstructed theta is a bit more forward than the thrown one. Andrei wondered whether this is not related to the effects of his simulation, mainly that rear clusters are eliminated because they are too far in z even though they belong, so this would skew theta to smaller values. KLOE first clusters showers using only r/phi information then splits up using timing/z information, whereas IU considers all information simultaneously. More work is needed.
  3. Any other business:
    1. Light guide gluing issue: Elton requested that we discuss whether the light guide partial poor glue contact issue can be simulated. David knows where that can be done in the code but it is tricky to estimate the size of the area involved and check for particles going through that area. It is not simply an issue of opacity but also of surface roughness, etc, and refraction/reflection should be included. Zisis suggested that we carry out dedicated cosmics runs (of a few days each) to compare cell to cell within a module and the same cell form module to module, since the SiPMs are the same in the ESB test setup. David will speak more with Elton on this, and Regina will discuss it internally as well.
    2. Collaboration meeting: it was agreed that a single presentation including Will's and Andrei+Irina's work would be made in the Calorimeter session of possible, otherwise in the Offline session.
    3. Next meeting will be on May 23 at 11:15am, and the one after on May 30th in the afternoon (time TBA).