Minutes-5-5-2011

May 5, 2011 FDC meeting

Agenda

1. Production
   • Status (Dave)
   • Wire position scanning logbook page 564 (Lubomir)
   • End window material (Bill)
2. Electronics (Fernando, Chris)
   • Status
   • Rigid-flex stuffing
3. Engineering status (Bill)
4. Chamber testing (Beni)
   • Equipment needed for Blue Crab
   • Pressure measurements
5. Other

Minutes

Participants: Eugene, Bill, Dave, Roger, Beni, and Lubomir.

Production

- Dave: Two cathode frames type 3 (with ground planes with holes) are assembled waiting for the rigid-flexes and ground wires to be glued on them. One wire frame was strung, the wires glued and now being soldered. Expect to be ready by the end of the day, then we will do position and tension measurements. We started also cutting foils for the third cathode plane and the second wire frame is also ready.

- We discussed the configuration needed to test the first chamber: end window, cathode type 3, wire plane, cathode type 3, end window, plus empty frames to make the same thickness as of the full package. We will use the plastic gussets. Bill wanted first to do gas leakage tests

Electronics

- Chris: got an answer from the company for the stuffing of the first 100 rigid-flexes. Bill and Lubomir: we need 18-20 for the first chamber next week; Chris will talk to them.

- Beni made pictures (pages 561-563) of the pre-amps that we use now on the prototype and then verified with Fernando the resistor settings. So we have for the cathodes 2.6mV/fC (high gain, RC=1, DR at 5% = 130fC or 338mV) and for the anodes (with and without discriminator) 0.77mV/fC (low gain, RC=0, DR at 5% 260fC or 200mV). The dynamic ranges we observe correspond to these values. Before, there was some confusion, we assumed we had 0.62mV/fC for the anode cards.

Engineering

- Bill can't find a good solution for storing the cathode foils. The jig plate for the package assembling is in the machine shop.

Chamber testing

- Simon reported his results about strip resolution and calibration. He used a new procedure (better pedestal subtraction), explained in pages 557-560 of the FDC logbook, that improved the strip resolution by ~20%. Eugene: such procedure may work in different ways on the central and side strips and one may use the sample range defined by the central strip also for the side strips. This however is difficult to implement within the fADC125 firmware.

-->