Minutes-6-13-2013

June 13, 2013 FDC meeting

Agenda

1. Production Construction Tracking (Dave)
   • Spare package status
2. Engineering (Bill)
3. Full electronics test [1], [2], [3] (Beni, Lubomir)
4. Other

Minutes

Participants: Bill, Dave, Chris, Nick, Simon, Vlad, Beni, Eugene, and Lubomir.

Production

- The spare package with four cells was opened last week on Thursday down to the top of the cell #5 (second from the bottom) to fix the gas leakage in an O-ring of the spacer ring there (the O-ring was mashed). The place on a wire showing a "point noise" in cell #4 (wire frame #27) was cleaned. Then we put again the four cells together, this time swapping the top two wire frames: #27 put on the top and #28 below it. The gas leakage was fixed.

- At the beginning of this week Vlad tested cells #5-3. The "point noise" disappeared. Another type of noise was also present at three places on the strips coming from wire frames #27 and #28. We observed it long time ago when tested these wire frames and it comes from positive HV traces on the back of the PCBs at the place where the are laminated to the solid part of the G10 wire frame. The frequency of this noise varies between 100-3000Hz and is visible only on the strips at the place where the traces leading to the strip connector are close to the HV trace. Definitely, it is the wire frame responsible since when we swapped the wire frames the noise showed up on the new cathodes. The only way to fix it is to drill the wire frame from the back, but it is not worth doing it since this is only in three places and the frequency is not that high.

- On Wednesday we installed one new cell and right after the meeting we installed the last cell of the last (spare) package! In these two cells we put the thicker version of the spacer ring to study the feasibility for cluster counting. Now the spare package is being flushed with gas.

Full electronics tests

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