Revision as of 14:29, 18 April 2016

April 14, 2016 Drift Chamber meeting

Connection

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.

Agenda

1. Detector updates
   • CDC update (Beni/Mike)
   • FDC update (Lubomir, Vlad)
     • Cathode Gain Calibration
     • plots for monitoring
     • photon background in the Hall, Photo-effect x-sections
2. Electronics (Fernando, Chris, Nick)
3. NIM Papers
   • new CDC ShareLaTex repository
   • svn ls https://halldsvn.jlab.org/repos/trunk/publications/GlueXFDC
4. fADC125 meeting (Naomi, Cody, Beni)
5. Other

Minutes

Participants: Curtis, Naomi, Mike (CMU) Eugene, Fernando, Beni, Luke, Simon, Nick, Chris, Vlad, Sergey, Amanda (detector group), Tyler (detector group), Pablo (detector group), and Lubomir (JLab).

Detector updates

- CDC has been successfully fixed after the "near-miss" event. The card that Nick suspected for noise was tested with a scope and was OK. Fernando: "the electronics saved the day" (i.e. the detector).

- Vlad reported on the FDC gain calibration. He did this before, but now the cathode resolution was improved and he uses now higher statistics (~1M hits per chamber). In the attached plots we see the distribution of the gain coefficients is getting narrower with each iteration - 4 in total. Some channels tend not to be calibrated producing tails in the distributions. Vlad will also work on parallelizing the calculations: separate job for each chamber.

- Lubomir proposed

fADC125

- Naomi is still looking at the differences between firmware and emulated output using the long mode (8) cosmic runs.

• Run 11016 2 CDC fadcs were playing up: roc25 slot 9, even ch 36-40 and roc28 slot 16, even ch 36-40 - there were small errors in 4/5 of hits (firmware time too large by 1 or 2 units (0.8ns), and integral too small by 5 to 8). There were a small number of problems with the FDC fadcs (differences in time and pedestal) but nothing significant.

• Run 11017 All CDC & FDC fadcs were ok. For this run the trigger holdoff had been increased to 30us.

• Run 11075 There were many errors in the same two CDC fadc as in Run 11016, and also in one FDC fadc: roc62 slot 17 even ch 36-42 show same behaviour. For this run the bufferlevel had been set to 1.

- Naomi noticed that the fadc configuration parameters in the BOR data read back from the fadcs in run 11075 is corrupt for these 3 boards, ch 36-41 (all) in the CDC boards, and channels 36-47 in FDC roc 62. These include more than the dodgy channels mentioned above. This indicates a problem reading from the chip. If it were a write problem, the discrepancies between firmware/emulator would be much larger than observed.