Minutes-9-15-2011
September 15, 2011 FDC meeting
Agenda
- Production Construction Tracking (Dave)
- Status
- First package tests (Lubomir)
- Engineering update (Bill)
- Electronics update
- Chamber testing at EEL126 (Beni)
- Other
Minutes
Participants: Eugene, Bill, Dave, Mark, Simon, Beni, Glenn, and Lubomir.
Production
- Started stacking again the package; we have already installed the first cell and the first cathode of cell#2. The second cathode of cell#2 and the second wire plane are also ready for installation after replacing two wires (see explanations below). Cell#3: the wire plane is ready except that four broken resistors need to be replaced. The two cathodes for cell#3 were checked with a generator and a problem in one connector was found: attenuation of the signal on several channels; the conductive tape on that connector will be re-heated. On all the frames in this stack (except the bottom end window and wire frame) we put new O-rings, because we observed some gas leakage. All the cathodes for the first package are ready except one; it has been tensioned and the next operation is to cut the flaps.
- Beni asked if the problems with the conductive tape show up at the same place on the connector due to uneven pressure. No, but Bill proposed to install a manometer at the cylinder to monitor that the pressure that comes from the compressor outside. Regarding resistor braking, we decided not to use lead bricks during the gluing of the PCB ring.
- Testing the first two cells in the package. The first cell that was fixed before was tested again and all the channels were OK. Two problems on the second cell: one wire broken between the pad and the epoxy and a point source of noise inside the chamber was found. Not clear how did the wire brake since that place was covered with epoxy and then the wire was checked by the tension measurements. The noise showed up on one wire on both cathodes, pointing to a fixed position; that's how it was identified. Both wires were replaced. It was difficult to conclude what was the source of the noise: Case saw several kinks in that area. After the wire was removed we looked with a microscope and found a small fiber-like piece looped over the wire, but not sure if that was at the same place. To bubble to the packages we had to increase the flow to 100 ccpm (compared to 20 for the first cell before) meaning some increased gas leakage.
