[Solid_gem] minutes of November GEM monthly meeting

[Jianbei Liu]

Hi all,

Minutes from yesterday's GEM meeting have been attached to the meeting agenda and copied below.
https://hep.ustc.edu.cn/indico/conferenceDisplay.py?confId=8

follow-ups on testing the small 2-D GEM at THU (Yan)
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- final spatial resolution determined to be 204+-13 um using Fe55 data in a rather analytical way (previous preliminary estimate is quite consistent with this result, though) 
- estimated the "sparking rate" by looking at strip hit multiplicity (high multiplicity events taken as sparking events). Very tiny sparking rate(~10^-5)  observed this way.
- upgraded the Fe55 collimator to allow more flexible movement
- investigating the impact of non-uniform spacing between GEM foils on chamber performance by intentionally adding a spacer between 2 GEM foil frames on one side to increase the distance between the 2 GEM foils on that side (thus artificially creating non-uniform space between the foils).
- simulating the GEM performance with Garfiled++.

APV25 test at USTC (Cheng)
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- tested an APV25 chip with a home-made system (see slides for details of the system)
- observed reasonable output of APV25 when injecting a signal 
- but the APV25 output didn't look right when running in calibration mode.
  + it was suggested to contact Paolo or Condo for expertise

Status of APV25 readout electronics test at CIAE (Shouyang)
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- updated the readout system with an italian backplane
- results from dry running (without a chamber connected) looked reasonable 
- some anomalies observed when running with a GEM chamber
  + Condo commented via email before the meeting about potential defects of the ZIP connector which might be responsible for the anomalies observed. 


Jianbei