From GlueXWiki
Jump to: navigation, search

March 24, 2016 Drift Chamber meeting


  1. Instructions for Bluejeans meeting connection
  2. Meeting ID: 290664653
  3. To join via a Web Browser, go to the page [1] https://bluejeans.com/290664653.


  1. NIM Papers
  2. Detector Status
    • CDC update (Beni/Mike)
    • FDC update (Lubomir)
  3. Electronics (Fernando, Chris, Nick)
  4. fADC125 meeting (Naomi, Cody, Beni)
  5. Other


Participants: Mike (CMU) Luke, Beni, Eugene, Simon, Nick, David L. and Lubomir (JLab).

NIM papers

- Attached is the submitted version of the contribution to the VCI conference.

Detector and firmware status

- Beni: no HV trips in the CDC even when the gas was Argon-reach (when the CO2 switch-over didn't work). Testing with Cody latest version of the firmware which in addition to some fixes, has the option for PBIT parameter to be negative.

- For the first part of the run FDC had threshold for sparsification of 120 for all the channels, with TH=100 and TL=25. Since then we tried (with cosmics) individual thresholds of 7 and 5 sigma the widths of the pedestals, that however have to be bigger than TH which was set to 50 and 40. The problem is that TH is the same for all the channels in the module. Lubomir is studying the effect of the TH/TL on the resolution of the timing algorithm. This is done by comparing the time from the wire TDCs (using fADC125 trigger time as reference) and the leading edge time from the firmware for the corresponding strip signal. Results will be presented on the next meeting. In any case, for rest of the run we will use 5 sigma thresholds, since the data volume with cosmics from 120 to 40 threshold increased by only about 20%.

- The trigger time is reported in two words, the first having the most significant part. In f250 the first word has the less significant part of the trigger time, which is done to save space in case you don't need two words. We will discuss this on the next meeting.

- Lubomir: sometime the timing algorithm reports leading edge time bigger than the threshold crossing time (with the quality flag set to 1). Lubomir proposed to check if the leading edge is smaller than the threshold crossing and if NOT, to use the threshold crossing as a start of the integration and peak searching algorithm. Cody: it's doable. Will be discussed on the next meeting.

- Since the magnet is down we propose to get some straight track data. The proposal was accepted later on a run coordination meeting for 6 hours in total (2 on empty target).


- David for the open house: it would be good to have the spare package on the platform, will give people an idea what's inside the magnet. The downstream side will be closed with aluminum cup, we may leave the upstream opened or have a transparent cover.