October 21, 2015 Calibration

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GlueX Calibration Meeting
Wednesday, October 21, 2015
11:00 am, EDT
JLab: CEBAF Center, F326

Communication Information

Remote Connection

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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 https://halldweb.jlab.org/talks/2015/ .

Calibration Tasks

  • Update hit/reconstructed object variances in sim-recon
  • Add plugins to sim-recon/src/plugins/Calibration
  • Document calibration procedures
  • Calibration Challenge


  1. Announcements
  2. Summary of Detector Performance
  3. Calibration Data Taking
  4. Calibration Tasks
  5. Subdetector Reports
  6. Future Simulations
  7. AOB


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

  1. Announcements
    • Mark Ito reported that we have a new Lustre-based work disk as of last night, so the partition might need to be remounted and links to paths other than "/work/halld" will need to be fixed. The available space has increased from 14 TB to some unknown number less than 350 TB (the size of the partition).
    • SQLite files are known to not work on Lustre partitions, so if you are using a SQLite-based CCDB file, then either use an official version kept on the /group disk, or copied to a local (scratch) disk.
  2. Summary of Detector Performance
    • Information is still needed for the tagger detectors. Curtis will follow up at the next beamline meeting.
    • The document should be updated with the new information that was reported at the last collaboration meeting.
  3. Calibration Data Taking
    • Since fully-reconstructed reactions provide cleaner data sets for calibrations, Sean listed a few possible simple channels that could be used for calibrations. Cross sections should be added to the list, along with efficiencies for those channels that people are already working to reconstruct.
  4. Calibration Tasks
    • Sean added a section to the meeting page for major calibrations tasks that need to be done.
    • We discussed the prospects for doing a "Calibration Challenge" exercise before the spring run (December?) that would involve running calibration codes on a given run to "re-calibrate" the run to the extent that the process can be automated. Several aspects of this idea were discussed included:
      • Should we try to recalibrate the run "from scratch" (closer to the conditions in the beginning or the run) or calibrate a perturbation on top of the current calibrations (closer to steady-state running conditions)?
      • What should be the initial conditions for the constants?
      • What is the scope of the exercise? (i.e. which calibrations should be run)
      • What are the requirements for the different calibration codes?
    • Sean will discuss some of these points offline with various subgroups and come back with a more detailed proposal next meeting. A submeeting will probably need to be spun off to plan for this.
    • Note that the scope will depend on getting calibration plugins added to sim-recon.
  5. Subdetector Reports
    • FCAL - Adesh is working on hardware gain balancing, and discussing per-channel timing calibrations with Mike S.
    • BCAL - There are issues with the clustering algorithm that are being investigated. This is a longer-term project. Elton updated his GlueX Note for the low-level calibration definitions to reflect how they are currently being used in sim-recon.
    • CDC - Simon adjusted the overall CDC gains to give better definition between the curves due to different particle types. He has implemented some constants and code in his own sim-recon branch to correct for the CDC sag. He is still testing these corrections - ask him for the branch name if you are interested.
    • FDC - Lubomir is working on implementing a DANA plugin to generate the histograms, etc. needed for FDC calibration. He is currently comparing the results of this plugin with those from his standalone code.
    • TOF - Nothing new.
    • Start Counter - Nothing new.
    • TAGH - Nathan has implemented a functional form for the timewalk correction suggested by Elton that includes a term that takes into account saturation of the PMTs. Initial tests show some improvement.
    • TAGM - Alex B. is studying the alignment of the microscope in order to understand the shifts he showed at the collaboration meeting.
  6. Future Simulations
    • We have defined conditions for simulations of next years' conditions. Elton pointed out that a solenoid current of 1300A would be a more conservative choice. Sean will update the CCDB, and Mark I. will then run some test jobs.
  7. AOB