BCAL Reconstruction Meeting 2013-06-20

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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. Will to check whether second cluster appears mostly in the outer layers, due to the "curving" of the shower.
  4. Will to turn off noise in the code and recheck his DeltaPhi and DeltaZ cuts. In Progress.
  5. Zisis to dig up the number of expected p.e. from past work.


  1. Action Items
  2. Updates
    1. Will
  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:
    1. Dark hits: Will looked into the dark hits (on vs off). Sees a sizeable effect (e.g. 5.0->4.6 on slide 1). These are not coming from 'new' hits, but rather are present because of the contribution of noise to signal events, causing extra hits. This is expected. Also, he sees 22/1000 (slide 2) single ended hits. Perhaps high threshold causes this or noise is not large enough. These had no TDC threshold requirement, just the standard 4mV FADC one. During the experiment, of course, once we have experience from operating conditions, we will be able to fine tune the thresholds.
    2. Extra Clusters: new plots by Will show that extra clusters show up significantly in the outer layers (slide 3) and this could be related to the 'bending' of the shower in the outer layers, as reported during the June 2013 Collab Meeting (z or theta cuts are not set correctly to capture the bent shower and therefore those events appear as extra clusters. Also, events outside the BCAL range appear (slide 4). This could be related to how the IU algorithm averages angles in spherical coordinates. The same effect is not visible in KLOE (cylindrical coordinates and different algorithm).
  2. Update: Following a request from Kei, Will simulated charged pions into the BCAL and looked at cluster matching to tracks (slides 5 and 6). The choice of the cuts (slide 5) and form of Delta-Phi is unknown. It occurs in DParticleID. The black box on slide 6 has the same Delta-z as the numbers on slide 5 but the Delta-phi is different owing to its dependence on momentum. Questions: are the out-of-the-black-box 50% events extra clusters? Also, we see events with Delta-phi up to 180 deg, so on opposite of BCAL. Could some of these be from hadronic showers that create neutrons (then these can go anywhere)? Suggestion: look at this picture using slices corresponding to forward theta (say 20 deg), and then 45 deg and 90 deg to see if these are related to the aforementioned bending of the showers.
  3. Next meetings: June 27 (Zisis will try to connect from Athens) and July 11 (David will run the meeting).