November 6, 2013 Tracking CDC/FDC

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Meeting Time and Place

Wednesday November 6, 2013 at 11:00am At Jefferson Lab, the meeting will be held in F326


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  1. Announcements
  2. Status Update
  3. Tracking
  4. Calorimetry
  5. Other systems


Present: Sean, Amiran (NU); Curtis, Naomi (CMU); Beni, Simon, Eugene, Lubomir, Dave L. (JLab)

  1. Announcements
    • The BCAL group presented their preliminary thoughts on calibrations in the Calorimetry meeting the previous day. They plan to present a proposal for their calibration tables at the next meeting. (PS. The TOF group plans to do the same.)
  2. Status update
    • The first set of draft calibration tables were made available for discussion.
    • Both the CDC and BCAL groups would like to have additional scintillator paddles installed for taking data with cosmics. There appears to be enough room underneath the detector, but the exact extent needs to be measured before further plans can be made. Lubomir said that the space under the magnet is filling up fast and he will try to take some photos of the hall so we can look for places to put the scintillators. The possibility of putting paddles above the detector is still an open question.
    • Curtis said that survey results should be put into the DocDB.
    • Sean is looking into standard codes for aligning multiple detectors.
  3. Tracking
    1. CDC
      • The time-to-distance calculation depends on the exact gas mix. Naomi had generated tables for this calculation corresponding to different gas mixes, and it was agreed that these should be stored as calibrations.
      • Some more work is still needed on the alignment table. Naomi pointed out that we should save the location of the up- and downstream endplates separately.
      • The two hit resolution parameter in the simulation (CDC_TWO_HIT_RESOL) is 25ns, which was generally agreed to be too small. The simulation parameters should be updated based on experience with the actual detector.
      • In the simulation, the distance-to-time calculation is made using a parameterization that involves a total of 8 parameters, and includes the effect of the magnetic field on drift times (which is roughly 20%). If this parameterization is used, then the parameters should be made into constants. A lookup table (i.e. the inverse of the time-to-distance table) could also be used. Sean agreed to look into historical details on this.
    2. FDC
      • The FDC is being moved in and out the magnet, and it is mechanically stable except for shifts in z. Work is being done to enable a survey when the FDC is sitting the magnet.
      • There are several tables currently in the CCDB which are either not used or are still works in progress.
      • The FDC group will present what alignment constants they need at the next meeting.
  4. Calorimetry
  5. Other systems