November 4, 2015 Calibration

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GlueX Calibration Meeting
Wednesday, November 4, 2015
11:00 am, EDT
JLab: CEBAF Center, F326

Communication Information

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Talks can be deposited in the directory /group/halld/www/halldweb/html/talks/2015 on the JLab CUE. This directory is accessible from the web at .

Calibration Tasks


  1. Announcements
  2. Calibration Data Taking
  3. Calibration Tasks
  4. Subdetector Reports
  5. Future Simulations
  6. AOB


Attending: Sean (NU); Curtis, Mike S., Will M., Naomi (CMU); Simon, Beni, Adesh, Lubomir, Alex B., Luke, Elton, Justin, Mark I., Nathan (JLab); Mahmoud (FIU)

  1. Calibration Data Taking
    • Sean has started updating the list of cross sections for processes that can be used for calibration,
    • Sean and Adesh will discuss updating the estimate for the amount of FCAL data that is needed.
  2. Calibration Tasks
    • The Performance Summary is looking good, except for a few missing sections.
    • Sean highlighted the need to update variances and make sure that they properly propagate through the code.
    • Sean gave an overview of the meeting that was held yesterday to discuss the Calibration Challenge. There was good discussion of goals of the exercise. The difficult part of the exercise will be the details of integration, and these were discussed as well. Sean is organizing some test runs, and a meeting is planned for next Friday to review progress.
  3. Subdetector Reports
    • FCAL - Adesh reported that the pedestal evaluation was based on Fall 2014 data, and looking at Spring 2015 data gives slightly different pedestals (besides the already reported differences in mode 7 and mode 8 data). This will result in different gains, so he will recalibrate the gains, update the CCDB, and use these as the basis for doing the hardware gain balancing.
      • Adesh is also working on deriving timing offsets for the FCAL by just looking at the block-by-block variations within shwoers. He will compare these to Mike's results from matched tracks. Elton and Beni pointed out that one has to be careful that the inclusion of the FCAL in the trigger does not bias these results.
      • Jon Zarling is working on the FCAL efficiency and should give some results at an upcoming Calorimetry meeting.
    • BCAL - Mike has George's time offsets and is working on integrating them into our current setup. A rearrangement of the current tables might be needed, Mike will talk to BCAL folks about this.
    • CDC - Mike reported the latest status at DNP, he found good success applying the sag and drift time corrections in reconstruction and alignment. He's currently working on dealing with a few edge cases. He mentioned that we could use more cosmic data with longer readout windows.
      • Simon asked about the prospects for a pull request to include these these corrections into the sim-recon trunk. Mike said that he'll be ready after cleaning up the edge cases and making some final checks.
    • FDC - Lubomir is working with SImon on integrating his FDC reconstruction code into the standard tracking code. It is more sophisticated, with strip+wire reconstruction, and drift time corrections. He'll then compare the results with both codes using straight tracks to see what the improvement is.
    • TOF = No news.
    • SC - Mahmoud is working with Sean on converting the timewalk calibrations to satisfy the requirements for the Calibration Challenge.
    • TAGH - Nathan is preparing the timewalk corrections and plugin to add to sim-recon.
    • TAGM - Alex is also finalizing his plugins.
  4. Future Simulations
    • Mark ran some simple test jobs, and Sean checked to see that their output was broadly reasonable.
    • Yesterday, Mark, Justin and Sean had a discussion, and agreed to only run bggen simulations (no beam-only), and to increase the photon energy range to E(gamma) = 4 - 12 GeV. This increased range will allow us to study if events from lower photon energy are leaking into physics analyses looking for events generated in the coherent peak, and to study exclusive events that have larger cross sections at lower photon energy that can be used for calibrations.