Minutes-5-3-2012
May 3, 2012 FDC meeting
Agenda
- Production Construction Tracking (Dave)
- Production status
- Third package refurbishment status
- Third package tests (Lubomir)
- Engineering update (Bill)
- Electronics update (Chris)
- Tests with first package at 126 FDC E-log (Beni)
- Other
Minutes
Participants: Bill, Dave, Chris, Nick, Simon, Beni, and Lubomir.
Production
- Dave: for package #3: wire planes 4 & 13 were deadened, now all the elements for this package are ready. Package #4: wire planes 24 and 25 ready for deadening, will be done on Monday. Chris will put components on wire plane 26 tomorrow. Anatoly is gluing daughter cards on cathode 47. Tina working on cathodes 49 and 50. Casey is filling the groove on the second type-1 cathode to be converted into type-2.
- Now we have four cells in package #3 installed. After the first cell installed and tested we put the next three cells on Wednesday, Thursday and Friday at once without tightening the chamber in between. On Friday after starting the gas we found huge leakage from the top spacer ring. It turned out the O-ring was smashed at one place. We suspect it happened because of the grease and incorrect use of the installation metal pins. When you insert the pins up into the new holes during the next cell installation, the pin can lift some of the frames and create gaps in between them. When you have gap the O-ring can stick to the surface above the groove (due to the grease), and then get out of the groove. To exclude this from happening again, when inserting the metal pins we should always apply force from the top (by fingers) to avoid separation of the frames. It is dangerous because you can damage an O-ring anywhere in the already installed cells which will require re-installation of the whole package. In case we have more problems Bill will consider designing a tool for pulling the pins. The damaged O-ring was replaced on Friday and we started flushing the package with gas.
- Withe four cells in the third package after 6 days flushing with gas we have 130ppm oxygen with 220 sccpm gas flow. A gas leakage that we had before was significantly reduced by putting a 5mil shim in between the bottom gusset ring and the end window. Now the leakage detector shows between upper 10^-4 and lower 10^-5. HV was applied on the top cell without problems (2100V) and all the channels were tested with a source. Today we continue with the tests of the next cell.
Engineering
- Installation of the remaining two cells of the third package will require new metal pins. The pins that are now there are bent and can't go up. Bill ordered them and we will have them at the beginning of the new week. We discussed if we need better (and more expensive) pins: as long as we have spares we will be fine with these.
