Difference between revisions of "Minutes-7-15-2010"

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#* oxygen contamination measurements  [http://www.jlab.org/Hall-D/software/wiki/index.php/Image:Halld_gas_systemB_v2.gif Beni's scheme]
 
#* oxygen contamination measurements  [http://www.jlab.org/Hall-D/software/wiki/index.php/Image:Halld_gas_systemB_v2.gif Beni's scheme]
 
# Other
 
# Other
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<!--
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= Minutes =
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Participants: Fernando, Bill, Roger, Mark, Bob, and Lubomir (fewer people
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because of the trigger meeting at CNU at the same time).
 +
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== Production ==
 +
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- According to Tim, the PR for the clean room is awaiting Claus Rode's signature.
 +
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- Long discussion about the production procedures. Bill included in the Fast Track also the wire frame production, the wire stringing, and the testing of
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the chamber layers. The file is linked above (as jpeg) and is open for
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discussions and improvements. Bill asked Mark to look at the file (with Fast
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Track from Tom) and give his comments. 8 technicians will be involved full day
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and will produce one layer for 6 days, but realistically we assume 8 days. For
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30 layers it will be 240 working days. In addition, two scientists will
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assemble the stack and do HV and cosmics tests. The exact tests are not yet
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defined, but the idea is to use all the time available for such tests, but not
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more than needed for the layer production. Fernando asked about the cleaning
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of the wire frames after soldering and we discussed different options for
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ultrasonic cleaning. Fernando wanted to have a flow chart of the production
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with dates, so that he knows when the different components are needed for the
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production. One of the main unknown is when realistically we can move to the
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off-site space and start organizing the production.  The plan is to have the
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wire frames by 8/24 (first article) and 9/20 (all 30). According to Fernando
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we will have the PCBs by 7/19 (first article) and by 8/19 (all). The PR for
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the cathode foils will be submitted next week and the timing of their
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production is not known yet, but Roger has contacted the company: they can do
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the first article by the middle of August (assuming the procurement doesn't
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take a lot of time). Using this information, Lubomir will start working on the
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flow chart with dates on it.
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- Bill explained us his ideas about the wire stringing. He will use the strong-back that is at IUCF. Lubomir will take care of bringing the
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strong-back to JLab. The idea is to use tape pads to hold the wires at the
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right positions before gluing and soldering them. The wire positions will
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adjusted by hands (or with some tool) using the camera. We discussed once more
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different options for the tension measurements.
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- the templates for the  rohacell arcs will be ready next Wednesday. Two students will start cutting the arcs, supervised by Mark. Bill said the most
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important is to have the I.D. cut correctly. The arcs will be stored in a box
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and then they will start gluing the rings.
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== Electronics ==
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- Fernando: CEM was awarded to produce the PCBs. After getting the first article (two of each) on 7/19, the PCBs will be tested by Fernando within
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two weeks before starting the mass production. In parallel, the first boards
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will be given to an outside company for stuffing, they will be tested again and
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then we will continue with the stuffing of all the boards.
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- Lubomir looked with the differential probe at the output (with 18m cable) of the new anode and cathode cards. The dynamic range of the anode cards is
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about 2/3 of the range of the cathode cards; according to Fernando this is
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normal and comes from the difference in the gains. This explains the cutoff in
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the fADC spectra discussed before.
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== Cathode redesign ==
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- Roger is ready with the design, except for a few cosmetic changes. He will send the Gerber files to the company by tomorrow and expects estimations
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from the company for 70 cathodes by the middle of the next week. At the same
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time he will start the PR paperwork, so that he can submit it as soon as he
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gets the quotation from the company.
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== Full-scale prototype test results  ==
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- Lubomir showed several Beni's plots, linked above. Based on high statistics cosmic data, the mean ADC, measuring the total charge from the wires, goes
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down with the drift time. Same was observed before for the maximum amplitude,
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using the fADC data. This can be explained by ~0.1% oxygen contamination. Beni
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also did measurements at different, by 20%, gas flow rates, but there's no
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visible change in the results.
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- To measure the oxygen contamination we need a pump at the end of the oxygen sensor, as discussed last time. The problem is that the pressure there should
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not be less than 0.5 atm, according to the documentation of the sensor. Beni
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also confirmed this talking to the company. We will look what are the
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parameters of the pump that we have. We may need a relieve valve to keep the
 +
pressure there above half atm.
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-->

Revision as of 15:49, 15 July 2010

July 15, 2010 FDC meeting

Tentative Agenda

  1. Production
  2. Electronics: update (Fernando)
  3. Engineering
    • Cathode foil: update (Roger)
    • Cathode frame prototyping
  4. Full-scale prototype tests
  5. Other


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