June 4, 2014 Calibration

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GlueX Calibration Meeting
Wednesday, June 4, 2014
11:00 am, EDT
JLab: CEBAF Center, F326

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  1. Announcements
  2. Status Update
  3. Tracking
  4. Calorimetry
  5. Other systems
  6. Simulations and Calibrations


Attending: Sean (NU); Curtis (CMU); Eugene, Simon, Lubomir (JLab); Zisis (Regina)

  1. Status Update
    • There is a new CCDB release that treats 1D row-wise and column-wise tables in the same manner. Sean has verified that it works, once he found out that GetCalib() returns false when the table is correctly loaded (!).
    • Sean is doing some final sanity checks and will check in his first round of changes in the next couple days. These will depend on the new CCDB version.
    • Sean updated the Constants_to_Review page. This can serve as a list for the various groups over the summer to update based on their first data. A few old lines of code have already been taken care of. Review of the geometry classes used in reconstruction is ongoing.
    • Simon updated the tracking code to use a time-to-distance table based on the parameterization used in the simulation and Naomi's B field variation correction (discussed below).
  2. Tracking
    • Lubomir reported on his work on FDC alignment using cosmic test data for package 3. This procedure assumes the wire planes are located accurately, and allows for each cathode plane to have an offset, rotation, and change in pitch. Using this data, he obtains a 150 micron resolution for the wire planes, and a 150-200 micron resolution for the cathode planes. Some improvement in the cathode alignment can be made. For instance, it's known that some of the cathode foils have gaps of a few hundred microns between them, so as there are 3 foils per layer, we would potentially need 3 sets of (offset, rotation, pitch) and two gaps.
    • Naomi reported on her scheme to correct the drift times for the variations in B field. The plan described here. Basically, it involves a correction to the drift time that is linear in the B field. She also looked at the effect of the radial B field on drift times and found it to be <2 ns for nearly the entire CDC. This can be safely neglected for now.
  3. Calorimetry
    • Zisis and Sean will keep in touch to develop a plan for updating the BCAL calibrations as manpower is available.
    • Eugene asked about the plan to analyze FCAL cosmic data. It is not known who is working on this; Matt should be consulted.
  4. Simulations and Calibrations
    • Work at NU is stalled due to cluster problems.