Difference between revisions of "Minutes-5-20-2010"

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- Kim received the third quotation for the PCBs from TriLab; the price is more than $200K, which is factor of 5 higher than the CEM's price. Fernando generated the step files for the PCBs, Bill checked for consistency with his 3D model: three holes had to be modified and Kim did it. Kim will submit the PR for the PCBs.  
 
- Kim received the third quotation for the PCBs from TriLab; the price is more than $200K, which is factor of 5 higher than the CEM's price. Fernando generated the step files for the PCBs, Bill checked for consistency with his 3D model: three holes had to be modified and Kim did it. Kim will submit the PR for the PCBs.  
  
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- We discussed the noise bursts we observed on the FDC signals. Beni identified the source: the CAEN HV crate used for the scintillator PMTs. At the same time we discussed why the noise on the bottom cathode is stronger than on the top (see FDC logbook page 457, linked above). Possible explanantions: additional ground plane on the top, different grounding on the different cathodes. Bill, Fernando, Mark and Lubomir looked at the prototype after the meeting. It is also strange that the bursts are correlated with the trigger (seen from the same picture); Beni's explanation: the noise is induced also on the trigger input.
  
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== Cathode redesign ==
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== Electronics ==
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- 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.
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Roger is working on the Bill's modifications, will have the cathode design ready soon.
  
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- 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.
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== Full-scale prototype test results ==
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- 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.
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- 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.
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== Cathode redesign ==
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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.
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- Lubomir is analyzing the data from the fADC125 tests and showed two pictures. The firs one (linked as "one event using fADC125" above) shows
  
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== Cosmic tests ==
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- Beni:
  
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- On Tuesday the 3-layer prototype was installed back at the stand for testing with cosmics.
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== Other ==
  
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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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- Bill had a good news: the workshop is getting a CNC horizontal milling machine
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Revision as of 17:53, 20 May 2010

May 20, 2010 FDC meeting

Tentative Agenda

  1. Production
  2. Electronics
    • fADC125 status (Fernando)
    • PCB status (Kim, Fernando)
    • grounding (Fernando, Lubomir)
  3. Cathode redesign Bill's changes proposed on the last meeting (Bill, Roger)
  4. Full-scale prototype test results
  5. Other



Minutes

Participants: Bill, Mark, Casey, Simon, Eugene, Glenn, Fernando, Beni, Lubomir, and Gerard on the phone

Production

- Bill has given updated drawings with our requirements for the off-site space to Ron Lauze. Ron will work on the infrastructure of that building.

- Bill has reviewed the production planing document linked above. There were several questions regarding the testing of the FDC layers and packages with cosmics. What we want to do will depend on the available time. For now we assume one day-night for testing per layer. We will come to this again after creating the production flowchart (Bill will take care about the latter). Fernando explained us the procedures related the the PCB inspections/tests. We need to set-up a place for testing, preferably in 117, and have one person trained for that. Bill mentioned that (from mechanical point of view) the most important is the quality of the PCB edges.

Electronics

- Fernando and Gerard informed us about the last week fADC125 tests. The module was installed in the VXS crate in 126 and connected to three FDC cards (top, bottom cathode and an anode). The tests were done using Gerard's code to configure the module and read the data into a file. Beni wrote a code to read the file from root. The DAQ group will work on incorporating the fADC125 into CODA system. For the beginning, they promised us (within two weeks) to write a simple interface to the module so that Beni can include it in the cosmics set-up. We discussed the heating issues we had with the modules in the VXS crate. Beni said there were problems with the F1TDCs there. Gerard asks us to be cautious and not have the fADC powered for long time (hours).

- Kim received the third quotation for the PCBs from TriLab; the price is more than $200K, which is factor of 5 higher than the CEM's price. Fernando generated the step files for the PCBs, Bill checked for consistency with his 3D model: three holes had to be modified and Kim did it. Kim will submit the PR for the PCBs.

- We discussed the noise bursts we observed on the FDC signals. Beni identified the source: the CAEN HV crate used for the scintillator PMTs. At the same time we discussed why the noise on the bottom cathode is stronger than on the top (see FDC logbook page 457, linked above). Possible explanantions: additional ground plane on the top, different grounding on the different cathodes. Bill, Fernando, Mark and Lubomir looked at the prototype after the meeting. It is also strange that the bursts are correlated with the trigger (seen from the same picture); Beni's explanation: the noise is induced also on the trigger input.

Cathode redesign

Roger is working on the Bill's modifications, will have the cathode design ready soon.

Full-scale prototype test results

- Lubomir is analyzing the data from the fADC125 tests and showed two pictures. The firs one (linked as "one event using fADC125" above) shows

- Beni:

Other

- Bill had a good news: the workshop is getting a CNC horizontal milling machine

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