Difference between revisions of "Minutes-6-9-2011"
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#* Wire Position Measurements | #* Wire Position Measurements | ||
# Other | # Other | ||
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= Minutes = | = Minutes = | ||
| − | Participants: Bill, Dave, Chris, Beni, | + | Participants: Eugene, Bill, Dave, Chris, Caleb, Beni, Simon, and Lubomir. |
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== Production == | == Production == | ||
| − | - | + | - End of last week we assembled the first production chamber, run gas over the weekend, on Monday applied HV and was tripping (1uA threshold) at very low voltages: ~20-30V for sense wires and somewhat higher (~30V, one sector was at -500V for short time) for field wires. Then we found ~1-10MOhm between HV and ground and practically all the pads on the PCBs, even between opposite PCBs on the wire frame that have no electrical connection. The conclusion was: the wire frame got wet (most likely the Rohacell) when it was cleaned in the ultrasonic bath. We tried to dry it with a lamp and then with a heat gun; didn't work. Then today we put it a big vacuum chamber at the Test Lab to take the moisture out. The person servicing the vacuum chamber mentioned that it went down to 10^-4 torrs for ~2hours, much slower than usual (~20min) which indicates there was a lot of moisture there. |
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- Cathodes: we have the third (type 3) and fourth (type 1) cathodes mechanically ready, waiting for the rigid-flexes; on the fifth cathode (type 3) the mylar will be tensioned today. By tomorrow we will have also the second end window (2mil mylar) ready. | - Cathodes: we have the third (type 3) and fourth (type 1) cathodes mechanically ready, waiting for the rigid-flexes; on the fifth cathode (type 3) the mylar will be tensioned today. By tomorrow we will have also the second end window (2mil mylar) ready. | ||
Revision as of 18:31, 9 June 2011
June 2, 2011 FDC meeting
Agenda
- Production (Dave)
- First chamber assembly: HV problem
- Spacer ring: gas leakage
- Second set wire frame and cathodes
- Other
- Engineering (Bill)
- Vacuum chamber
- Ultrasonic cleaning
- Rigid-flex gluing tool
- Other
- Electronics (Fernando, Chris)
- PCB schematics update
- Other
- Chamber testing
- Wire Position Measurements
- Other
Minutes
Participants: Eugene, Bill, Dave, Chris, Caleb, Beni, Simon, and Lubomir.
Production
- End of last week we assembled the first production chamber, run gas over the weekend, on Monday applied HV and was tripping (1uA threshold) at very low voltages: ~20-30V for sense wires and somewhat higher (~30V, one sector was at -500V for short time) for field wires. Then we found ~1-10MOhm between HV and ground and practically all the pads on the PCBs, even between opposite PCBs on the wire frame that have no electrical connection. The conclusion was: the wire frame got wet (most likely the Rohacell) when it was cleaned in the ultrasonic bath. We tried to dry it with a lamp and then with a heat gun; didn't work. Then today we put it a big vacuum chamber at the Test Lab to take the moisture out. The person servicing the vacuum chamber mentioned that it went down to 10^-4 torrs for ~2hours, much slower than usual (~20min) which indicates there was a lot of moisture there.
