Minutes-11-10-2011

November 10, 2011 FDC meeting

Agenda

1. Production Construction Tracking (Dave)
   • Production update
   • Second package tests (Lubomir)
2. Engineering update card positions (Bill)
3. Electronics update (Chris)
4. Test set-up at EEL126 (Beni)
5. TDR (Lubomir)
6. Other

Minutes

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

Production

- Dave on second package production: first cell was installed, all the elements for the second cell are ready except to populate the wire boards (Chris will do it tomorrow). Cathodes for the third cell also ready, working on the fourth cell cathodes. Third wire plane was strung and wires glued and soldered. The HV caps were replaced on the fourth, but we have problems so far with the dark current there; may require additional change of some capacitors. The fifth wire frame was laminated today. Problems with field wire spools, Dave will discuss it with Steve Christo from Hall B.

- Lubomir: The installation of the first cell was much easier due to the new hubs/pins Bill designed. Flushing with gas since Tuesday, chamber is very tight (bubbles at as low as 15 ccpm). Setting HV on it was also easy. Vladimir tested all the channels with a scope and 55Fe: all working fine. But, we again see a noise at the same place (around HV trace on the fourth +HV sector) we saw on three cells in the first package, this time with higher frequency (~2.5 kHz). Will rotate the top cathode by 30deg after the meeting to make sure we have the same problem here.

Engineering

- Bill showed a scheme for the positions of the signal connectors in the package; it will be linked to this/next meeting after some update. Related to that, once more we discussed the FDC naming convention linked above.

- Cooling system: need to build tool that will help forming the right tubing diameter (120cm), maybe out of plywood. Casey may do it tomorrow.

- Right after the meeting Bill installed the holding brackets on the first package.

- Gas system: following the discussing on the collaboration meeting yesterday, Lubomir made estimates about the oxygen diffusion into the gas volume due to the open end of the thin tubes used at the output of the cells. The diffusion length per second is less than a cm. The speed in the thin tube is at least 10cm/sec which at 2m length makes the oxygen concentration negligible. Today we tried using one bubbler after the thin tubes, it worked better than without thin tubes, but stopped bubbling after running for ~30 min at a flow of 80 ccpm. Needs further studies.

Electronics

- Chris (not at the meeting) will work next week on the pre-amps: installing cooling brackets and testing; possibly Vladimir will help him.

Chamber testing at 126

- Beni: Will get two more VXS crates, need more 20Amp power sockets, Mark will help him.

TDR

- Lubomir started working on the FDC part of the TDR, current version will be at the link above, right now very pre-preliminary. Beni suggested to concentrate on the technical description of the detector and just refer to the CDR for the motivations and MC studies.

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