February 17, 2011 FDC meeting
- Production (David)
- Blue Crab status
- Electronics (Fernando, Chris, Roger)
- Rigid-flex and foil production status
- Engineering (Bill, David, Lubomir)
- Lessons learned from the test wire plane FDC Log Book, page 551
- Wire stringing modifications
- Chamber testing
- Plans for full package tests (Beni)
- Tests with the middle chamber (Lubomir)
Participants: Bill, Mark, Dave, Chris, Simon, Beni, and Lubomir.
- Dave: the stringing table and the cathode tensioning system are the only main items not yet moved to Blue Crab. The stringing table will be modified before moving there: 6 holes in the granite have to be drilled and different other new pieces mounted there. Will have three computers in the clean room, one new and another two used, all Windows. The temperature in the clean room is lower than the required one and the vendor will fix the problem tomorrow. It turned out the temperature control is not in the clean room and we are not supposed to use it.
- The plan for the next month work at Blue Crab includes: cathode frame inspection, building PCB rings, cutting, aligning, and gluing cathodes. We will start with old PCB and damaged cathode foils and then use the new/good ones. The ultimate plan is to build parts for one chamber that has to be tested before the mass production.
- Dave's working on the procedures/travelers, we can't start production without these documents.
- Bill asked if we need summer students for some work starting end of May.
- Chris: 50 cables were reworked, but 13 of them came short by a foot. It turned out those are CDC type cables. Even if the length is not critical, we decided not to accept such cables for the FDC. Simon was concerned that we need a plan how to bundle, run the cables. Bill has some preliminary drawings, but everybody agrees that this is important.
- The rigid-flex will be produced as it was in the first article. We requested additional 140 flexes to be used for exercising and as spares in case of cathode foil failure. In total we will have 615 flexes.
- There was a long discussion what we have learned from the stringing:
- Bill questioned whether the wire vibration (used in tension measurement) is the reason for the several broken wires between the epoxy and the solder. Suggested using computer to control the amplitude and frequency of the generator. Dave will try connecting to the generator with LabView. Lubomir thinks the wires were broken by the leads while trying to keep them on the solder. The use of conductive rubber (from Fernando) will prevent this because one can put the leads away from the soldering pad. Bill suggested using pogo pins so that fewer people can do the measurements.
- To prevent wire breaks at that place we can put later additional epoxy to cover the wires at that region, but Bill wants to avoid having epoxy on the solder.
- Bill wants to try soldering before gluing. Lubomir: in this case it will be difficult to cover the wires to prevent from solder balls, without touching the wires.
- We discussed again different types of solder and epoxy we and other groups have used.
- Bill wants to make tools for the wire taping.
- Lubomir is concerned having magnets (for the weight shield) close to the weights because of the possibility for attracting the weights and wire breaking.
- Bill wants to know if we can use aceton, it's need for the cathodes. Lubomir will study this issue.
- The CMU conductive epoxy will be tested soon. We can have more from CMU.
- Beni started discussing what is needed for the full package tests that will start in the middle of the next year (see the above link). It will be a multi-crate system that require new modules. The only concern so far are the F1TDCs that will not be ready by that time. Instead we have to use the old F1TDCs with translation boards.
- Lubomir is scanning the middle chamber. The variations of the bottom/top strip ratio are as big as for the top chamber.