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| − | September 22, 2011 FDC meeting | + | September 29, 2011 FDC meeting |
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| − | Participants: Eugene, Bill, Dave, Chris, Simon, Beni, Vladimir, Mark, and Lubomir. Vladimir is the new graduate student from MePhi Moscow. | + | Participants: Bill, Dave, Chris, Simon, Beni, Vladimir, and Lubomir. |
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| | == Production == | | == Production == |
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| − | - Dave: started checking the continuity before taking the frame out of the stringing table: on the wire frame for cell#5 (that was just finished) one broken wire was found and was fixed today. Epoxy will cure overnight and tomorrow we will put on the stringing table the wire frame for cell#3 to fix one wire there too. Wire frame for cell#4 is ready, just needs final cleaning. On the last cathode (for the first package) the rigid-flexes were glued to the cathodes. Next, they will be tested with a generator and then the daughter cards glued. | + | - Dave: Working on the sixth (last) wire frame for the first package; all wires soldered and today will do tension measurements. The fifth wire frame will be populated tomorrow by Chris. On Monday we will do the wire deadening on that frame and then it will be ready for stacking. Started working on the end windows and first cathode for the package #2. |
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| − | - We discussed the reason for these broken wires, so far we had always one broken wire per plane. On the last one found on the frame for cell#5, we looked with a microscope. The wire was broken at the end of the epoxy right where it touches the soldering pad. The wire tip was bent at ~90 deg at this place somehow. It was not clear if the tip was inside or outside of the epoxy. The wire was checked by doing tension measurements on it. The only operation that happened later was cutting the wires and then doing the continuity measurements. One explanation could be a cold solder and then the wire brakes when twisting it. Dave suggested also that if the wire is above the PCB it may not be fully covered with epoxy and is easily breakable a that point. | + | <!-- |
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| − | - End of last week we put three cells in the package after replacing two wires in the second cell and changing all the O-rings. | + | |
| − | The first three cells were tested channel by channel by Vladimir. All were OK except no signal on one wire channel in the new third cell, most likely broken wire. The third cell was conditioned with HV relatively fast, but then suddenly developed very high current; we left it over the night at 1kV and then in the morning it was OK again.
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| − | - We found again gas leakage with the three cells in about the same area as with the two cells. The amount of leakage was about the same (bubbling above 80-100 ccpm) as with the two cells, indicating that the problem is in the second cell. Bill suspects it is the seam on the wire frame between the PCBs that may have been somehow damaged during the installation. To fix the broken wire and look at the leakage place we decided to unstack the package down to the second wire frame. After finding the broken wire on the frame that is on the stringing table we decided to continue with this tomorrow.
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| | == Engineering == | | == Engineering == |
Revision as of 15:20, 29 September 2011
September 29, 2011 FDC meeting
Agenda
- Production Construction Tracking (Dave)
- Status
- First package tests (Lubomir)
- Engineering update (Bill)
- Electronics update (Chris)
- Chamber testing at EEL126 (Beni)
- Other
Minutes
Participants: Bill, Dave, Chris, Simon, Beni, Vladimir, and Lubomir.
Production
- Dave: Working on the sixth (last) wire frame for the first package; all wires soldered and today will do tension measurements. The fifth wire frame will be populated tomorrow by Chris. On Monday we will do the wire deadening on that frame and then it will be ready for stacking. Started working on the end windows and first cathode for the package #2.
