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May 5, 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. Electronics (Fernando, Chris, Nick)
  3. NIM Papers
  4. fADC125 meeting (Naomi, Cody, Beni)
  5. Other


Participants: Curtis, Naomi, Mike (CMU) Eugene, Fernando, Beni, Luke, Simon, Nick, Chris, Vlad, and Lubomir (JLab).


- Naomi discussed some issues ( a bug fixed in the timing algorithm?) and future firmware developments, like self-triggering.

- Lubomir looked at some runs with the special f125 firmware for the TRD studies and found sometimes the event number (within the same data bank) is different for the different modules. Looking at the time stamps (trigger time) indeed they correspond to events from the past or the future. Sometimes (even the event number per buffer is one) there are several consecutive events from one module. Beni: that is possible if the buffer level is set to >1 in mode 8.

Detector updates

- Beni: the HV and LV of FDC and CDC were turned off for the summer. As discussed later with Fernando we plan at some point to turn the HV on to look at the CDC card that had issues over the last run and also to test the stability of the FDC HV. Beni also lowered the gas flow and bypassed the alcohol bubblers. The latter is needed to reduce the effect of the alcohol on some type of glue used in the CDC, which however is not critical.

- Most of the remaining time we discussed Vlad's results on the cathode calibration, see attached presentation. The expression to be minimized consists of two terms: (1) the total charge on the top minus the bottom charge and (2) the residuals of the fit (with Matheson function) of the amplitudes for each hit. Vlad demonstrated the convergency of the procedure - after each iteration the distribution of the gain coefficients is getting narrower. However, once the amplitudes are corrected by the gain coefficients, the strip resolution deteriorates. Vlad: it might be a result of the strongly non-uniform hit distribution over the chambers. Eugene proposed to start with a simpler minimization using only the second term, to apply it for one cathode only on a small area and also to add a normalization term. Discussions continued after the meeting.

NIM papers

- Beni started working on the CDC paper from the svn directory. He wants to have the first version ready before the summer so that people have what to work on during the break.