FDC Weekly Meeting
Date: May 23, 2007
Participants: Daniel, Simon, Brian, Kim, Roger, Chuck, Fernando
Next Meeting: Wednesday, May 30, 2007 @ 1:30 p.m.
New Prototype Cathodes
- CCT continues to work with Sheldahl on the issues with making our cathode boards. We clearly do not have the full story, but here is what seems to be the case. CCT has made several sets of cathode boards for our small-scale prototype. Now they cannot make boards without shorts between the strips. They claim (even though they are using the same material as they used for our previous planes) that there is a problem with the material. There are also rumors that due to safety issues, they are not using the chemicals for the etching. This is most likely the case. They claim that the current cathode material has a chrome flashing. They believe that if Sheldahl replaces this with a nichrome flashing, their process will work. CCT stated emphatically that they will give us a final answer by June 4. - Brian has contacted an EE who used to be with F. Sauli's group about providing European contacts. - Roger has also found an alternative manufacturer and he will forward this information on to Brian. - There is still hope that we can find a materials manufacturer who can supply the material to make a single piece cathode board.
- No progress on the HVTB and STB development this week as Kim was busy on other projects. - Fernando reported that the existence of magic circuit boards made from HVPF may be a myth. - We discussed how to make the connections from the cathode boards to the back side of the cathode frames. The present idea is to include a cut-out and feed a flex cable through the cut out to the back side connector. We want to prototype this. Roger will look into purchasing some parts and pieces that Brian can use to play some games.
FDC CD-2 Document
- DSC and Simon had a phone conference with Richard Jones regarding the different options that we want simulated for the FDC active area. We provided a written document to Richard (see the Hall D FDC wiki). He will get to work on preparing the geometry files and pass them on to David Lawrence and Matt Shephard. Hopefully he can complete his work within a week.
Magnetic Field Tests
- Simon has contacted Bogdan W. from Hall A. He has two small Si counters that he can lend us. We shall continue to look for other alternatives. DSC contacted Alex after the meeting regarding IUCF contacts.
- We discussed the issue of carbon fiber support rings in the magnetic field and magnet quench issues again. It is clear that we need some outside information. - Brian will contact Paul Brindza on this topic when he gets back from his trip to Russia. - We also began to discuss alternative materials that are non-conducting, for example Kevlar that could replace the carbon fiber, or even e-glass.
- Now that Brian is back from his lengthy hiatus, we began discussing cathode backing options that replace the 5-mm of low density Rohacell with something even lighter. Brian will begin to think about. One idea that came up was a foam composite, with a thin layer of low density Rohacell to define the surface flatness (say 1 mm) and a 4-mm backing of ultra-low density foam (large air pockets). More to come on what we can do. Once Brian has a few ideas, we can go about computing the thicknesses and compare to the 5-mm Rohacell option.
- The FDC short-term work list has been posted on the FDC web site (see http://www.jlab.org/Hall-D/detector/fdc/). This is continually being updated and DSC welcomes any feedback or comments from the group.
Minutes prepared by Daniel. Send any comments or corrections along.