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April 14, 2011 FDC meeting


  1. Production status (Dave)
  2. Electronics
    • Status (Fernando,Chris)
    • fADC125 requirements
    • Cathode foil inspection
  3. Engineering
    • Status (Bill)
    • Radiation tests with conductive tape (Lubomir)
  4. Chamber testing (Lubomir)
  5. Other


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


- 11 cathodes were inspected so far; one panel was damaged by us because of incorrect packaging.

- the first production cathode was glued tensioned and the frame was glued to it; cutting the flaps and the holes is next. Some of these procedures still require signatures. Cutting the second production cathode started with problems with the cutter. Bill thinks it is the granite surface that damages the blades. Using harder blade and treating the granite surface must help. Bill also made modifications to the cutter to prevent wobbling of the blade.

- a PCB ring was glued to be used for the first production wire frame. Tests with light show the surface at the seams is not perfectly flat. Anatoly will work on this. Next steps: trimming the Rohacell OD on the wire frame and laminating the PCB ring. We will accelerate this so that we can work on the wire frame in parallel with the cathodes. Bill asked if it will be acceptable to use parafin to cover some parts of the Rohacell OD that is needed for the ultrasonic cleaning. Lubomir will investigate this.

- Dave is working on the paperwork for making holes in the clean room. We decided to have 4 holes: two in the cathode area and one in each of the small rooms. The holes will be used for nitrogen, compressed air and chamber gas mixture supply.

- We received the solder wire (0.65mm) from UVA that we will use for wire soldering at the beginning. Al has progress with the software (for the Parker controller) used to find the wire position.


- Chris: nothing new, waiting for quotation for the rigid-flex tinning.

- Yesterday at the tracking meeting we discussed possible modifications for the fADC125: increase of the gain to cover the whole 12 bit range that was requested by the CDC people. This is not acceptable for the FDC and as seen in the document linked above we are happy with the current version. Eugene insisted that we don't want to have two fADC125 versions which will delay their production and increase the costs, and that this will not solve the problem with the dynamic range. Now they are considering modification of the termination of the CDC pre-amps. In any case for us the fADC125 will not change.


- Bill is working on the package assembly jig plate and placed orders for: the new 3M tape gluing tool, cutter modifications, and spacer ring needed for the end window gluing.

- One rigid-flex sample set (two samples) that had higher radiation exposure was taken out of Hall C yesterday. It showed some residual radiation but we still were allowed to have it in 126. The two samples passed the electrical tests successfully. Bill had an idea how to do the mechanical tests: by gluing a Kapton piece on the top of the rigid-flex.

Chamber testing

- The prototype is now in vertical position. To test it, we used 55Fe source triggering with one of the wires. Data was taken, but no results yet due to some software problem; waiting for Beni to fix it.

- At the end we also discussed possible ways to replace the radioactive sources when testing the chambers at Blue Crab. Possible ways: using nitrogen laser (needs special gas mixture), X-ray tube like TV tube. We expect safety issues like with the use of radioactive sources at Blue Crab, so we are giving up unless it's absolutely necessary to have some kind of source there.