Difference between revisions of "Minutes-8-11-2011"

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# Other
 
# Other
  
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= Minutes =
 
= Minutes =
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- Wire deadening: the wire deadening of the first production chamber (wire plane #2) was successful. The thickness of one sample was measured by a microscope from Olympus company and they found it ~66 microns along one wire. The surface looked very good. We have permission to use the W&M microscope to check samples. Bill is going to look at different wires to make sure the tickness is the same.  
 
- Wire deadening: the wire deadening of the first production chamber (wire plane #2) was successful. The thickness of one sample was measured by a microscope from Olympus company and they found it ~66 microns along one wire. The surface looked very good. We have permission to use the W&M microscope to check samples. Bill is going to look at different wires to make sure the tickness is the same.  
  
- The chamber from 126 with cell#1 was moved to Blue Crab and the wire plane #1 was replaced with wire plane #2. All the cathode channels were tested with the testing card. We found that several daughter card connectors didn't make good contact at some channels. After re-connection (sometimes several) finally we got them working. One bad connection was found between the flex at the cathode (the first one of this kind!) and it was fixed after re-heating/pressing without changing the conductive tape.  
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- The chamber from 126 with cell#1 was moved to Blue Crab and the wire plane #1 was replaced with wire plane #2. All the cathode channels were tested with the testing card. We found that several daughter card connectors didn't make good contact at some channels. After re-connection (sometimes several) finally we got them working. One bad connection was found between the flex at the cathode (the first one of this kind!) and it was fixed after re-heating/pressing without changing the conductive tape. We found also on the top cathode at an area that was exposed directly to the AC blower in 126, that the silver epoxy got some brownish color. It turned out that 9 days ago after a thunderstorm overnight the AC in the EEL switched from cooling to heating and the temperature in the morning reached 95deg F. The Ac was fixed by 10am. It is not clear if it was the heat or humidity that caused this discoloration. We will prototype it, but the resistivity at this place was still low.  
  
 
- Bill wants to try on one end window to use scotch-weld for gluing the thick mylar, he is afraid of the bubbles that appeared somewhere on the end windows.
 
- Bill wants to try on one end window to use scotch-weld for gluing the thick mylar, he is afraid of the bubbles that appeared somewhere on the end windows.
 
   
 
   
 
== Engineering ==
 
== Engineering ==
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- Bill: we received the strong-back for the package; ordered legs for it (ready in two days). Also ordered second set of gusset rings and hubs needed for the spare package, to be ready in two weeks. Simon: it will be good to put the strong-back on the chamber in 126 to see if it will solve the flatness problem.   
 
- Bill: we received the strong-back for the package; ordered legs for it (ready in two days). Also ordered second set of gusset rings and hubs needed for the spare package, to be ready in two weeks. Simon: it will be good to put the strong-back on the chamber in 126 to see if it will solve the flatness problem.   
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== Chamber testing ==
 
== Chamber testing ==
  
- Beni: DAQ is now working with the modified VXS back plane. More studies showed that the drift time spectra looks very different from what we had with the prototype for 90/10 Ar/CO2. Most likely in the first chamber we have problem with the gas mixture in addition to the flatness and HV problems. Also Beni found that the efficiency of the chamber now is ~60% and was 99% before, but it could be a result of the new DAQ and/or related software. For that, it would be good to have a working chamber to troubleshoot these problems.
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- The new package (old cathodes, end widows and new wire frame #2) was moved to Blue Crab on Wednesday.
 
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- Beni on testing Humi-seal with radiation: the effect we expect to see is the polymerization on the wires (Molter effect) and it happens when both: there's high radiation, and the HV is on for a long period of time. So, if we want to see these effects it will take long time and high radiation doses. However, it is known that one can use alcohol in the gas mixture to prolong the chamber life. Therefore, we should start these tests but at the same time we can use Humi-seal in the chambers production and, if we have to, we will add alcohol to the gas mixture.
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- After the meeting there were additional discussions. It is clear that we want to have a working production chamber at 126 and at the same time to do these long-term studies with Humi-seal. Going back to the prototype to study only the Humi-seal would not be an efficient solution. That's why it was proposed to replace the wire frame #1 with wire frame #2 and test it at 126. Frame #2 also has Humi-seal on the capacitors and we can do all the tests simultaneously. In addition we can add the strong-back to that package to test the flatness.
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Revision as of 18:46, 12 August 2011

August 11, 2011 FDC meeting

Agenda

  1. Production Construction Tracking (Dave)
    • Status
    • Wire deadening
    • Other: Humi-seal, silver epoxy overheating
  2. Engineering (Bill)
    • Update
    • Package flatness
  3. Electronics (Chris)
    • Update
    • Pre-amp card connectors
  4. Chamber testing at EEL126
    • Cell#2 status
  5. Other


Minutes

Participants: Bill, Dave, Chris, Beni, Simon, Glenn, and Lubomir.

Production

- Dave (see link above): all wire frames for the first package were laminated. Wire plane #5 ( the first to go in the package) will be populated tomorrow by Chris, followed by putting Humi-seal on the caps, and then wire deadening. Techs are working also on cathodes for cell#6: cathode type 1 is ready and the foils for type 2 are being cut.

- Wire deadening: the wire deadening of the first production chamber (wire plane #2) was successful. The thickness of one sample was measured by a microscope from Olympus company and they found it ~66 microns along one wire. The surface looked very good. We have permission to use the W&M microscope to check samples. Bill is going to look at different wires to make sure the tickness is the same.

- The chamber from 126 with cell#1 was moved to Blue Crab and the wire plane #1 was replaced with wire plane #2. All the cathode channels were tested with the testing card. We found that several daughter card connectors didn't make good contact at some channels. After re-connection (sometimes several) finally we got them working. One bad connection was found between the flex at the cathode (the first one of this kind!) and it was fixed after re-heating/pressing without changing the conductive tape. We found also on the top cathode at an area that was exposed directly to the AC blower in 126, that the silver epoxy got some brownish color. It turned out that 9 days ago after a thunderstorm overnight the AC in the EEL switched from cooling to heating and the temperature in the morning reached 95deg F. The Ac was fixed by 10am. It is not clear if it was the heat or humidity that caused this discoloration. We will prototype it, but the resistivity at this place was still low.

- Bill wants to try on one end window to use scotch-weld for gluing the thick mylar, he is afraid of the bubbles that appeared somewhere on the end windows.

Engineering