Difference between revisions of "Minutes-8-16-2012"

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Participants: Eugene, Bill, Dave, Simon, Vlad, Beni, and Lubomir
 
Participants: Eugene, Bill, Dave, Simon, Vlad, Beni, and Lubomir
  
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==  
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== Cathode production ==
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- Dave: working on 8 new cathodes to be used in the second package. The bottleneck is the card gluing since we have not decided if we want to change the procedures.
  
 
== Cathode corrosion ==
 
== Cathode corrosion ==
  
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- Lubomir: a test with cathode foils, Viton/EPDM O-rings and water was done (at Blue Crab dirty area). First, the O-ring samples were pressed against the foils with a lead brick, also using G10 and aluminum plates to equalize the pressure. After a couple of days, water (from the tab) was put on the samples. Corrosion appeared immediately on the next day: very well pronounced on the EPDM sample and resembling the same dark traces that we had on the cathodes of the first and second packages (see first picture above), also some corrosion but with lighter color on the Viton sample. Olga did SEM analyses on the two sample foils at the places of the O-rings: second link above. Generally, the experiment was not done in a clean environment and tab water was used, so you see a lot of dirty  stuff like chlorine. At the same time sulfur is visible in almost all the areas of the EPDM sample, while for the Viton sample sulfur is present in much smaller areas visible with high magnification. We started the same experiment inside the clean room using distilled water; expect results next week.
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- Lubomir about the SEM results: On the wire samples some small crystals (~3um) are seen containing sulfur, Olga counted about 25 of these on 2cm wire length; too small quantity to account for the copper damage on the cathodes. On the EPDM surface - no conductivity and very low yield from the microscope - still one see some sulfur on the used EPDM, and much less or nothing on the virgin EPDM and on the prototype EPDM. Dave will check if the virgin and used EPDMs are from the same batch.
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- Three other test experiments are running. One with production cathodes and a wire frame that started more than two weeks ago. Second one with similar samples using the small-scale prototype, running since yesterday when we were able to fix the HV. The third one is the Vlad's experiment using the vacuum chamber (picture linked) with same samples (EPDM, Viton with/without Apiezon) with same gas, but no HV, with some water inside to create moisture, all this heated with a lamp (only during the day) up to 80degC. It started yesterday; we will open the chamber on Monday.
 
- Three other test experiments are running. One with production cathodes and a wire frame that started more than two weeks ago. Second one with similar samples using the small-scale prototype, running since yesterday when we were able to fix the HV. The third one is the Vlad's experiment using the vacuum chamber (picture linked) with same samples (EPDM, Viton with/without Apiezon) with same gas, but no HV, with some water inside to create moisture, all this heated with a lamp (only during the day) up to 80degC. It started yesterday; we will open the chamber on Monday.

Revision as of 11:50, 17 August 2012

August 16, 2012 FDC meeting

Agenda

  1. Cathode production Construction Tracking (Dave)
  2. Cathode corrosion
    • Status [1]
    • Possible procedure changes
  3. Conductive tape technology
  4. Engineering (Bill)
    • Cathode strong-back
    • Other: epoxy tests
  5. Electronics (Chris, Nick)
    • PCBs
  6. TDR, pages 132-145 (Lubomir)
  7. Other


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