Minutes-12-2-2010

December 2, 2010 FDC meeting

Tentative Agenda

1. Production (David)
   • Blue Crab status
   • Frame production
   • ETC change request for FDC Tim's new schedule
2. Electronics (Fernando, Chris)
   • PCB status
   • Cathode foil production
   • Other
3. Engineering (Bill, David)
   • Wire stringing table model, camera, linear unit, weight
   • Movement system and position sensor
   • Other
4. Full-scale prototype
   • fADC to F1TDC comparison with 40/60 (Beni)
   • resolution simulations (Simon) FDC Log Book, page 545
5. Other

Minutes

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

Production

- Blue Crab status: the clean room construction started this week, walls are erected already.

- Wire frames (Bill): all wire frames inspected, we have 30 ready to go (out of 32), one is a little off the specifications, and another one is way off. Next step: gluing and laminating the PCBs that should start next week at Blue Crab. 16 cathode frames are ready; important is to check the depth of the O-ring groove.

- New schedule: we discussed the feasibility of the package full tests scheduled to start at the beginning of 2012. For that we will need enough electronics to equip one full package: 12 F1TDCs, 36 fADCs, 24 anode and 108 cathode cards. According to Fernando we will have the cards and the fADCs by June 2012 and the F1TDCs by Sep 2012. Eugene looked at the last schedule for the electronics and concluded that actually we will have a good fraction of the electronics ready by the beginning of 2012. A delay is expected with the F1TDCs and we discussed options to replace those with other types of TDCs. Beni raised the question about the additional modules needed for the DAQ, since we are going to have at least two crates. All these questions require additional information from Fernando and other people, so we will continue the discussion off-line and on the next meeting.

Electronics

- Chris cleaned and tested with 2500V channel by channel all the first article PCBs. So, now we have two sets of PCBs ready to be laminated. For the cleaning, he used first Vigon bath but was not enough, so he did the final cleaning with Flux-off bottles. The rest of the PCBs that were sent back to the company for cleaning are still there. Fernando ordered two solder types for the wire soldering that we will test.

- Roger who is now at the Allflex facility in Minnesota, informed us that the production of the first foils started. On Tuesday two panels were produced, one of them developed a wrinkle during the photo-resist stripping. We can still use such foils for practicing; it's good we have a lot of spare material. We don't know yet when they are going to ship the first article. Still, we decided to move two tables inside the Hall B clean room tomorrow afternoon, so that we have the place ready for the foil inspection.

- Bill informed us about accelerated aging tests done with the 3M conductive tape: the specialists are confident that it will last for 10 years, but the company is not going to state this officially. Bill will try another type (7303) of such tape that has pure epoxy.

Engineering

- Wire stringing: almost all the parts needed for the stringing table are ready. Bill showed details on the attached to the agenda figures.

- The controller for the stepper motor should be here within a week. Two people representing Acuity were at JLab today demonstrating their laser sensors. It turned out that the new sensor that has higher sampling rate (9.6kHz compared to 1.2kHz that we have now) has bigger spot size and doesn't see the 25um wires on the first prototype. They proposed to use another two-dimensional sensor but it is not clear if it can see our wires, and also the price is high. Casey will string several field wires with the nominal tension of 20g directly on the granite table, and we will try to measure the tension using our old laser sensor.

Full-scale prototype tests

- Beni was working with 40/60 Ar/CO2 comparing fADC and F1TDC resolution. With this gas mixture, compared to 90/10, the resolutions are closer still F1TDC gives better resolution. We switched today to Ar/methane/CO2 gas. Beni is also implementing the new fADC125 library from Bryan Moffit.

- Simon is studying the resolution for different gas mixtures with Geant simulations. Comparing 90/10 and 40/60 (pages 543 and 544) the spread of the drift time is smaller for 40/60 in the region up to 2mm, but bigger at 3-5mm. Expect more results for the next meeting.

Other

- The Allflex company asked for permission to mention our detector in their trade journals and advertisements. Eugene will inquire about the procedure for such a permission.