March 23, 2016 Calibration

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GlueX Calibration Meeting
Wednesday, March 23, 2016
11:00 am, EST
JLab: CEBAF Center, F326

Communication Information

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Talks can be deposited in the directory /group/halld/www/halldweb/html/talks/2016 on the JLab CUE. This directory is accessible from the web at .


  1. Announcements
  2. Subdetector Reports
  3. Calibration Tasks
  4. Simulations
  5. AOB


Attending: Sean (NU); Simon, Paul, Mark I., Will M., Alex B., Justin, Nathan, Elton (JLab); Mahmoud (FIU); Naomi (CMU)

  1. Announcements
  2. Subdetector Reports
    • FCAL - As discussed in the morning RC meeting, Adesh is updating the CCDB gain calibrations and the HV settings. Sean suggested that electrons could provide a cross calibration on the difficult inner ring.
    • BCAL - Will fixed an inconsistency with how DBCALPoint objects were using the effective velocities. Work continues on the clusterizer. George is studying the effects of the finite shower size on his determinations of effective velocities.
    • SC - Mahmoud determined new propogation time corrections. He also looked at the resolution in simulation, which is ~370 ps compared to ~270 ps in data.
    • TAGH - Nathan and Franz moved some counters around to get more consistent coverage. The CCDB tables need to be updated.
    • TPOL - Mike D. and Nathan are now seeing consistent results for the raw asymmetries. Nathan is working on determining the effective analyzing power in order to compare with Mike.
    • TAGM - Alex is finishing up his new timewalk algorithm. He is also updating his PS energy calibration for this run.
  3. Calibration Tasks
    • Data Validation - Sean described the RCDB "status" values he is using.
    • Calibration Train
      • Sean sent some details in this email. Performing the run quality control and consolidating several passes helped a lot. Skims are being written to the write-through cache. He launched last Friday and has been competing with several large CLAS simulation batches. One limiting factor at the moment is the time it takes for nodes to free up room for multicore jobs (he is using 16 cores at the moment) in this environment.
    • Spring 2016 Recon Checklist - fADC emulation can be checked off, TAC reconstruction added.
    • Mcsmear updates
      • Sean compiled a comparison of various monitoring plots run on data and simulation. We discussed them and this gave some useful input on where to focus efforts. Some highlights:
      • BCAL pi0 resolutions are worse in simulation than in data.
      • BCAL efficiencies are also slightly worse in simulation, though there's generally good agreement.
      • Until CDC gain calibrations are made, we'll want to make loose cuts on dE/dx
      • Track/BCAL matching is less efficient on the downstream end. Tracking improvements may help this?
      • Interesting patterns in the FCAL matching. We don't understand the distribution of FCAL/track distance for low momentum tracks.
      • TOF matching efficiency is overall low by ~15% in data. Simon mentioned we probably have to think about looking at the alignment of the individual bars.
  4. Simulations
    • Sim1 status - Sim1 production is done and on disk and tape. People are starting to look at these events. The size seems sufficient for now. Focus in the farm is on processing data.