Difference between revisions of "Minutes-5-6-2010"

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== Production ==         
 
== Production ==         
  
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- The plan is to have the space available starting Sep.1. Bill talked to Rusty and he has contacted two vendors for the clean room and will have a teleconference with them. We discussed also what can be done in 727 B.C. without the clean room if the space there is available.
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- The plan is to have the space available starting Sep.1. Bill talked to Rusty and he has contacted two vendors for the clean room and will have a teleconference with them. We discussed also what can be done in 727 B.C. without the clean room if the space there is available before Sep.1.
  
 
- Brian and Mark made estimates for the manpower needed for the different steps in the FDC production. Bill will review the procedures and the numbers. The estimates for some of the procedures are not so certain, either they have never been done or the experience is not so solid.  
 
- Brian and Mark made estimates for the manpower needed for the different steps in the FDC production. Bill will review the procedures and the numbers. The estimates for some of the procedures are not so certain, either they have never been done or the experience is not so solid.  
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Bill suggested moving the connector and opening for the rigid-flex outwards as explained in the above document. Roger will do this correction.
 
Bill suggested moving the connector and opening for the rigid-flex outwards as explained in the above document. Roger will do this correction.
  
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== Cosmic tests ==
  
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== Production space ==
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- On Tuesday the 3-layer prototype was installed back at the stand for testing with cosmics.
  
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- 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.
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- Beni: additional delays are needed for the cathode signals to have them within the ADC gate. Beni will use long flat cables for that. He is working on his code to reconstruct the hit position from the cathode strips above and below the wire plane. The cathode pedestals are wide: RMS of ~80 ADC channels. Fernando suspects the post-amplifiers are noisy. He suggested using the shaper board instead of the post-amps and look for change of the widths.
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- 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.
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== Electronics ==
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- 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.
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- 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).
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== Cathode redesign ==
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- 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.
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==  Cosmic tests ==
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- 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%.
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- 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.
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== Other ==
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- 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.
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- 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.
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Latest revision as of 15:32, 7 May 2010

May 6, 2010 FDC meeting

Tentative Agenda

  1. Production
  2. Electronics
    • update on oscillation problem (Fernando)
    • possible grounding improvement
    • PCB (Kim, Fernando)
    • fADC125 test plans (Fernando)
  3. Cathode redesign Bill's changes (Bill, Roger)
  4. Cosmic tests (Beni)
  5. Other
    • summer students, techs from FEL working on FDC project
    • talks at the Collaboration meeting FDC update
    • no meeting next week


Minutes

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

Other

- We started our discussions from the last point: what work do we have for the summer students. There are several projects related to the UVA equipment for wire stringing: setting up the position measuring system (camera with computer), help in the development of a system for tension measurements. Not exactly related to that, but very important, Bill, Brian and others started discussion what else is needed to use the UVA equipment. We will have more discussions on the next meeting, but for now we will contact UVA to bring the equipment at JLab and store it in room 117.

- There's a possibility to have techs/engineers matrixed from FEL to work on the FDC project. Roger made the point that whenever FEL finds funding for them, they will abandon our project. We have to make sure that their contracts have the clause that they first have to finish their responsibilities for us.

- everybody is encouraged the look at the FDC Collaboration talks linked above

- because of the Collaboration meeting next week we will have no FDC meeting

Production

- The plan is to have the space available starting Sep.1. Bill talked to Rusty and he has contacted two vendors for the clean room and will have a teleconference with them. We discussed also what can be done in 727 B.C. without the clean room if the space there is available before Sep.1.

- Brian and Mark made estimates for the manpower needed for the different steps in the FDC production. Bill will review the procedures and the numbers. The estimates for some of the procedures are not so certain, either they have never been done or the experience is not so solid.

Electronics

- Fernando reduced the gain on the new cathode cards from 3.2mV/fC to 2.6mV/fC and the oscillations disappeared. The noise level of the cards when looking at the output of the shaper board (low amplification) is 10-15mV peak to peak. The oscillations are explained as a result of the increased capacitance of the system. We may have to reduce the amplification further for the 6-layer configuration. Bill asked if one can simulate/predict the amplification that works for the final configuration. Fernando: it will be difficult, effects are not linear.

- There were very interesting proposals how to improve the grounding to alleviate the oscillation problem. Fernando proposed to separate the grounds of the different layers; now one ground foil acts as a ground of two layers. We discussed how to increase to area/number of the connections between the ground and cathode foils and also to use the ground foil/copper tape to shield the input of the pre-amps. Eugene proposed to add thicker aluminum foil ring on the top of the ground plane covering only the frame area. Certainly there are good ideas; Bill has to look what modifications can be done to improve the grounding.

- Kim got a corrected estimate from CEM when using g10 (instead of FR4): $400 more. Bill stated, the flatness they can hold +/- 0.004" is acceptable for us. No quotes yet from TriLabs. Kim was having problems creating the step files for the PCBs that Bill needed for the 3D model. Fernando and Bill think it is important, so Fernando will help Kim, it may take a week.

- Gerard Visser will be here next week. Fernando plans for Thursday (05/13) to have him working on the FDC prototype to check the fADC125. The module will stay with us, unless Dave Abbott needs it, and it will be very important to start working with it.

Cathode redesign

Bill suggested moving the connector and opening for the rigid-flex outwards as explained in the above document. Roger will do this correction.

Cosmic tests

- On Tuesday the 3-layer prototype was installed back at the stand for testing with cosmics.

- Beni: additional delays are needed for the cathode signals to have them within the ADC gate. Beni will use long flat cables for that. He is working on his code to reconstruct the hit position from the cathode strips above and below the wire plane. The cathode pedestals are wide: RMS of ~80 ADC channels. Fernando suspects the post-amplifiers are noisy. He suggested using the shaper board instead of the post-amps and look for change of the widths.

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