November 30, 2016 Calibration

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GlueX Calibration Meeting
Wednesday, November 30, 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 .

Calibration Tasks

  1. Spring 2016 Recon Checklist
  2. Mcsmear updates - mcsmear 20160323
  3. Data Validation
  4. GlueX Detector Performance Document

Upcoming Calibrations

  • Add timing information to FCAL clustering/inner ring calibrations? (Adesh/Matt S.)
  • BCAL TDC calibrations (Andrei)
  • TAGH alignment (Nathan)
  • Tagger energy map (Richard J.?)
  • TOF alignment (Beni/Simon)


  1. Announcements
  2. Run Planning
  3. Calibration Updates
  4. Alignment
  5. Simulations
    • sim1.2 planning
      • 30x data needed for FCAL, ~30% of Spring 2016 statistics. More needed for analyses?
    • Variation updates
      • Use "mc" for simulating data
      • Use "mc_generic" for simple tests
    • mcsmear updates
      • BCAL (Will M.)
      • FCAL (Adesh)
      • CDC (Mike S.)
      • FDC (Alex A.)
      • Tracking (Paul/Simon)
      • TOF (Beni)
      • SC (Mahmoud)
  1. AOB


Attending: Sean (NU); Simon, Thomas, Nacer, Adesh, Nathan, Brad, Mark I., Beni, Mark D., Eugene, Justin, Mike S., Lubomir, Alex A. (JLab); Will M., Naomi, Curtis (CMU); Matt S. (IU)

  1. Run Planning
    • Sean reported that cosmic data was taken before Thanksgiving with the f250's requiring 2 samples to be above threshold before a pulse is recored (previous default was 1), and this gave more stable results. Some edge cases are being worked on.
    • Naomi reported that the BOR records for the f125's are not showing up again. The saving of these records is still spotty.
    • Sean tested calibration jobs on the new farm nodes, and saw good scaling up to the number of physical cores (36). Beyond that his tests were dominated by fluctuations.
  2. Calibration Updates
    • FDC - Mike S. has been working on studying the tracking residuals. The current alignment parameters determined by Lubomir don't work with the sim-recon reconstruction. This seems to be due to differences in how cathode strips are treated when forming FDC hits. These differences are being worked out. Alex A. is also updating the errors on cathode clusters with <3 hits.
    • TOF - Beni has some preliminary results for efficiencies but needs to refine his selections. Tracking-based efficiency determinations are sensitive to the accuracy of the track reconstruction since the tracks are projected over a long distance - the previous alignment problems can affect them. Beni will study these biases in simulation - Sean will point him to the most recent efficiency plugin outputs.
  3. Alignment
    • We looked at the wiki page Mike S. put together to organize tracking alignment efforts. Mike mentioned that the CDC pull updates were essentially done, Alex A. and Simon were working on fixing some of the error conditions.
    • Lubomir mentioned that a consistent set of alignment constants had been written out. Sean said that it would be nice to have an official GlueX note of this, to prevent future confusion.
    • Sean is working on a scheme rationalizing the geometry classes in sim-recon, which should help with alignment efforts.
    • Mike S. mentioned that it is known that ver03 has some alignment problems. It seems better than previous versions. Kinematic fit results should still be viewed with extreme caution.
  4. Simulations
    • sim1.2 planning
      • Sean and Mark I. have been working on another round of simulations. These will be bggen events with E(beam) > 3 GeV. The preliminary goal is to generate 30 times as many events as sim1.1, i.e., ~30% of the number of triggers in the Spring 2016 data. Feedback is welcome.
    • A goal is to update detector-level efficiencies before this launch.
    • Variation updates
      • The use of CCDB variations is a constant source of confusion. Sean and Mark I. met and clarified the current policy of using "mc" for simulating data, and generated a new variation named "mc_generic" for which a set of fixed conditions are stored, useful for simple studies when no run number-dependence is required.
    • mcsmear updates
      • BCAL - Will has been studying the clustering of charged particles and will give a detailed report at tomorrow's Calorimetry meeting.
      • FCAL - The hit time resolution was updated from 200ps to 400ps based on Adesh's latest studies, and is now pulled from CCDB. Adesh is developing a scheme to record dead channels using LED pulser data for upcoming runs. The number of dead channels is very small, so the plan is to not incorporate this information from the Spring 2016 data. Efficiency information from Jon Z.'s studies will be useful in matching data and simulation, and can help decide if a bottom-up or top-down approach is needed.
      • CDC - Naomi said that she sent a list of bad channels to Sean after the last meeting. Sean didn't remember this, so she will resend the link.
      • FDC - Alex A. has a list of dead channels which he wants to do some checks on before the end of the week. Lubomir pointed out that Luke also has a list from tests done before the run. Sean will talk to him about extracting the information and comparing it to Alex's list.
      • TOF - Beni is looking into this.
      • SC - The timing resolutions were stored in the CCDB with the wrong units (ps instead of ns), and this was fixed yesterday. Mahmoud is looking into differences in efficiencies between simulation and data.