Minutes-8-25-2011

August 25, 2011 FDC meeting

Agenda

1. Production Construction Tracking (Dave)
   • Status
   • HV cap problem: [1],[2],[3],[4],[5]
2. Engineering (Bill)
   • Stack assembly procedure
   • Wire deadening images
   • Gusset ring
   • Other
3. Electronics update (Chris)
4. Chamber testing at EEL126 (cell#2) (Beni)
   • Results with new gas mixture: [6]
5. Other: how to assemble a package

Minutes

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

Production

- Dave: yesterday finished with stringing and taping wire frame #6, today did the position measurements and by the end of the day the wires will be glued. The cutter is now again operational and the techs will continue with cutting the foils for the cathode set #7; working also on the flaps for the cathode type 2 from set #6.

- HV cap problem (see pictures linked above). Everybody was surprised by the size and the abundance of the solder balls: 1-2mm (compared to the gap of 4.5mm between the pads) under more than 50% of the caps. Based on this observation, a decision was made on Monday to re-solder all the capacitors on the newly built wire planes. The above statistics applies for the two wire frames that were re-soldered by Anatoly so far. The leakage current after re-soldering went down to several nA for the whole frame. Not all the boards are like these: when we started testing the capacitors a month ago, Anatoly re-soldered the capacitors on another board, but we didn't see such solder balls there. After some discussions we agreed that it is worth informing the company. Chris will take care of the communications with them. Eugene: probably it's not worth pursuing this problem legally, but suggested to consult with the procurement.