July 22, 2010 FDC meeting
- 727 B.C. status
- production planing: 5 techs production schedule
- Electronics: update (Fernando)
- Cathode foil: update (Roger)
- Wire stringing design (Bill)
- Cathode frame prototyping
- Full-scale prototype tests
Participants: Eugene, Bill, Fernando, Glenn, Roger, Casey, Beni, Simon, and Lubomir.
- David Butler accepted the position of a FDC Construction Coordinator and will start on Aug. 2. Both Bill and Lubomir are confident he will do the job. He has expertise in working with PCBs which may be helpful for Fernando when testing our PCBs.
- No news about Blue Crab.
- Lubomir presented a Fatstrack version of the FDC production with 5 people occupied, linked above. It will take ~12 working days to produce one layer (one wire and two cathode planes). This is to be compared to the previous version with 8 people producing one layer for ~6 working days. In case of 5 people, two techs are working on the two cathodes (one of them with a ground plane), one electrician is soldering the cathode connectors and the wires, two technicians are preparing the wire frame and stringing the wires. Eugene asked about other intermediate options: with 6,7 people available. Bill: the schedule will become realistic when we start the production (everybody agrees). Fernando: we must include additional, probably only visual inspection of the electrical part of the wire frames before starting the stringing. Berni: we should include the machining (fly cut) of the wire frames in the schedule even if it will be done outside.
- Fernando: we don't have yet the first article PCBs. Recently, space was freed in F117 for the PCB testing. They are interviewing people for a tech position, to work on the testing.
- fADC: Gerard has now a version of the firmware that works at high rates. Gerard will soon include in the next release the auto-load of firmware, as well.
- a sample of clamps (made by TechEtch) that may be used to improve the grounding on the cathodes, was shown. Fernando also proposed the holes in the wire and cathode frames made to hold the cables, to be used also to improve the grounding.
- Cathode foils: Roger received quotation for 74 cathode foils (4 first article) at $1340 per cathode. We discussed what the yield would be and how many spares do we need. Eugene proposed 80 cathodes: 60 needed + 30% spares + 2 to exercise. Roger has started the paperwork for the PR.
- Cathode frames: Bill: when we have the foils we will need theframes. Bill will go ahead and submit a PR for the cathode frames: 30 of each type.
- The strongbacks are being shipped from IUCF, will have them in a week or two. Bill wanted to have sketches or pictures of the position and tension measuring systems that are worked out at UVA. Lubomir will contact UVA.
- The two Liping's students are busy with PRIMEX. We should start cutting the rohacells when we have people available.
- The new cathode frame prototype was glued to the kapton foil and the latter was cut at a diameter larger than the I.D. of the transfer ring. Next step is to create flaps, according to the Roger's design, and glue them.
Full-scale prototype test results
- Beni explained that the old estimate of the wire resolution of ~200microns has to be scaled up by ~40%. This is due to the fact that the drift times for the field configuration with zero voltage on the field wires, are ~40% bigger. Beni is working now with the bottom layer.
- The new rack is ready to be used for the gas system. Beni used the third flow controller for the IU chambers and freed the rotameter needed for the oxygen sensor. We discussed whether we need a relieve valve (Bill: or pressure regulator) between the pump and the oxygen sensor (see the scheme linked above). Because we use a low power pump we may not need the valve.