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June 16, 2016 Drift Chamber meeting


  1. Instructions for Bluejeans meeting connection
  2. Meeting ID: 290664653

Headline text

  1. To join via a Web Browser, go to the page [1] https://bluejeans.com/290664653.


  1. Detector updates
  2. NIM Papers
  3. fADC125 meeting (Naomi, Cody, Beni)
  4. Other


Participants: Sean (NU), Naomi, Mike (CMU) Luke, Cody, Alexander A., Simon, Nick, Chris, and Lubomir (JLab).


- Naomi is working on the gains: the phi-dependent gain variations are not correlated with the tube deformations. Mike is working on the time to distance calibration.

- Nick: on the top HVB that had issues over the last run he found some magnetic debris.


- Alex showed a presentation (linked above) about his studies of the FDC efficiency and resolution using higher level (DFDCHit) objects for runs with magnetic field. For these studies he applied some requirements for the track quality, like p>0.4GeV and more than 4 hits per package. The efficiencies look similar to the one with straight tracks, while the resolutions are worse. The cathode resolutions after taking out the magnetic field effects are about 300-350 microns. The FDC timing information is not used, so the residual distributions in direction perpendicular to the wires are almost flat.

- Lubomir presented plots showing drop (of about 30-40%) of the average charge with the drift time, probably due to some contamination. Comparison of the results for the runs since 2014 (first plot) doesn't show deterioration in the FDC performance. Correspondingly, the efficiencies (second plot) for drift distances > 4 mm drop sharply down to ~50% at 5 mm, however it corresponds to about 5% average drop. As we measured the Oxygen contamination to be < 50ppm, there must be something else in the gas.


- Cody: no timing measurements yet, needed for the busy signals.