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November 18, 2010 FDC meeting

Tentative Agenda

  1. Production (David)
  2. Electronics (Fernando, Chris, Roger)
    • PCB status
    • Other
    • Cathode foil and rigid-flex production
  3. Engineering (Bill, David, Beni)
    • Wire stringing status model.
    • Other
  4. Full-scale prototype tests
  5. Other


Participants: Bill, Fernando, Glenn, Eugene, Dave, Al, Chris, Roger, Simon, and Lubomir.


- Blue Crab status: the granite tables and other stuff was moved to make space for the clean room construction. We decided to keep 2 or 3 tables inside the office to be used for gluing the PCB rings and their lamination. Dave found office furniture that we can storage in Blue Crab as long as the accelerator people do not complain.

- All wire frames laminated with Rohacell. Most of them are fly cut and stored in our machine shop; we decided to move them to 126 to make sure they are not exposed to high humidity. Four cathode frames are ready, but Vision Machine had problems with the milling machine and the production will be delayed (this will not affect the production at all). The next step is to glue and laminate the PCBs.

- As requested by Eugene we have updated the FDC production budget linked above; it is needed urgently for the change request. Everybody is encouraged to look at it and make corrections if needed asap.


- Chris sent the PCBs back to the company for cleaning. Only the first article PCBs (two of each) are here and Chris is cleaning them at 126. They will be ready for gluing and laminating by the beginning of the next week. We have to test all the PCBs with HV applying 2500V, before using them in the production.

- Roger: Allflex confirmed they will start the cathode foil production the last week of November. After some iterations with the Gerber files for the rigid-flexes we also expect their production to start at the end of November, so that at the beginning of December we will have the first article: 25 rigid-flexes. These will be used also to exercise the soldering; for that we have to cut the connectors on the side of the cathode foils during their inspection.


- Wire stringing: Bill ordered the parts for the motion system frame. The wheels on the granite table have to be installed better before the other installations.

- Motion system: waiting for the Parker controller. Fernando will send Bill the link for the laser sensor with 200kHz sampling. Fernando tried using a generator and a speaker to vibrate the wires but the amplitude was very small. For now we will use the "scrubbing" method, later with the real wires we can try again using better speaker system.

- Bill ordered the second foil tensioner. Al is working on the heating device to be used for the 3M conductive tape.

Full-scale prototype tests

- Beni compared experimentally the wire resolution when using F1TDC (with discriminator card) and fADC125: ~180microns for F1TDC and ~250microns for fADC125 (page 542).

- Lubomir simulated with Garfield the drift time spectra for distances to the wire from 0 to 5mm with a step of 200um (page 541). Simon used these in his MC simulations (page 543). The Garfield model was calibrated using experimental data with 55Fe source.

- Lubomir investigated the relations between the strip multiplicity (that defines practically the event size), strip resolution, and reconstruction efficiency (page 540) for different thresholds, gas gains, and gas mixtures using cosmics. With a gas gain of 10^5, one can have ~3.5 strip multiplicity, resolution of ~150um at sufficiently high efficiency.