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April 29, 2010 FDC meeting

Tentative Agenda

  1. Production space
  2. Electronics
    • PCB (Kim, Fernando)
    • grounding/oscillation tests (Lubomir)
  3. Cathode redesign (Roger) beam hole, fdc left, cathode adapter
  4. Cosmic tests (Beni)
  5. Other
    • talks at the Collaboration meeting
    • open house


Participants: Fernando, Casey, Roger, Brian, Glenn, Bill, Kim, Simon, Beni, Eugene, Lubomir

Production space

- Tim is the contact person from our side for the 727 B.C. property. He will meet with Rusty to discuss our requirements and all the details. There was a meeting with the network people from the computer center. They will organize the network using their equipment. We will pay for the COX business connection.

- A document has been created (attached above) with the intention to list all the steps of the FDC production and describe them in terms of manpower and time. Lubomir will get help from Brian and Mark to estimate the manpower required for each step. The wire stringing procedure will be based on the UVA experience. Then Bill will review the document and we will continue with creating a flowchart of the production.


- PCBs: some minor modifications have been done and the design is now final. Kim got quotes from San Francisco Circuits ($76K) and CEM ($41K) for 28 of each board. Both are bellow our budget ($98K). CEM has special notes: quotation based on using FR4 instead of G10 material (not acceptable!) and that the flatness specs may not be achievable. Bill, Brian and Fernando discussed what is our actual flatness requirement. Kim expects one more quotation. Bill requested a solid model of the PCBs so that he can include it in his CAD design.

- The "power outage test" last Friday showed that the source of the oscillations is not external. After all the power was shut down at 6pm, the oscillations remained exactly the same as before. Same test was repeated on Monday early in the morning when the scope showed only few mV (on 10MOhm probe) random noise, and the result was the same. We moved the chamber back in the tent for testing. Lubomir did some investigations: the old cathode board had no oscillations when the cable was grounded properly. All of the new cathode boards showed oscillations that were reduced significantly in amplitude when grounding the cable from the chamber side. The oscillations are stronger at one side of the card; the speculation is that the line used for calibration that goes to the input of the preamplifiers that is at the same side, may be responsible for the feedback, but Fernando noted that the coupling is very weak. If nothing else works, Lubomir suggested to reduce the amplification of the new cathode cards so that they can be used for the prototype tests. Fernando will be testing the cards tomorrow (Friday).

Cathode redesign

- Roger discussed the plots attached above. Everybody agreed on the design of the beam hole (first plot). Roger used the unused corners of the foil to place connectors on which one can exercise the soldering. Roger showed the modifications he did at the above plots and got several suggestions from Bill and Fernando. Fernando will help Roger with the PR for the cathodes.

Cosmic tests

- In the last week tests with cosmics we were able to use only the anode cards. Beni showed several plots demonstrating that one can still get important information from these runs. The drift time spectra look much better compared to results from the Sr source tests: there's almost no tail at the end of the spectrum. Few runs were taken with two chambers with parallel wires, one on the top of the other. Beni showed the hit correlations between the two chambers and used this configuration to estimate the wire efficiencies. They are close to 100%, except at the end (shortest wires) where it is down by ~5%.

- Beni plans to include one of the chambers in the tracking, to predict the position of the track on the second chamber. He will also look at the correlation between the timing difference of the wires from the two chambers and the slope of the track as defined by the IU chambers.


- There will be two FDC talks at the Collaboration meeting: Lubomir will present the FDC status, and Beni will talk about the tests (cosmics and source) with the full-scale prototype.

- At the open house, this Saturday, we will have the 4th wire frame and one cathode frame (both in a plastic box) for demonstration in the Hall D tent.