FDC Weekly Meeting
Date: September 3, 2009
Participants: Daniel, Simon, Brian, Roger, Stephen, Beni, Fernando, Bill, Chuck, Eugene
Next Meeting: September 17, 2009 @ 1:30 p.m.
General Construction Updates
- The assembly jig on which the detector stack will be constructed is waiting for final pieces to arrive next Tuesday. We will then assemble it and do some dry fits to be sure there are no problems. - Bill has begun work on the FDC stack assembly document. He will work to make a draft available after next week's GlueX Collaboration meeting. The document will be fleshed out during the assembly process with relevant photographs.
Wire Frame Update
- Rich's work from this summer on the wire frames has been prepared as a report that he has turned over to Fernando. Fernando will circulate it shortly. - We have been doing additional inspection for frame P1. The worst HV bus is drawing about 300 nA. We inspected with the scope the surface of the HVTB and both sides of the STB. We have done some cleaning and did not see too much debris or surface contamination. We also did not see any big changes in the currents. We will use a warm air system to try to localize the problem and potential due more localized cleaning or use some humidity sealant. Stay tuned for developments. - In the full-scale prototype, there was a design problem with the circuit boards so the wire frames will be laminated to their neighboring cathode planes to give a gas seal. We will move forward with this work as we certify each wire frame as ready. Frame P1 should be certified shortly and then we will work to investigate frames P3 and P4. - We need to have a dedicated meeting to design what the schedule for work on the Phase 3 wire winding will be. The highest priority for work scheduling will be doing work on upgrades of the wire winding facility. This includes a better strongback design, the design and construction of precision combs, modification to the wire winding table, and a list of other items with the system. Stay tuned, more to come. - After the meeting we got an email from Keith Solberg at IUCF. They are developing plans to improve the wire winding room. It will be cleaned up and they are considering including temperature and humidity control. They asked us for specifications that would suit our needs. - The wire frame construction document is located at: /u/group/halld/Engineering/PRELIMINARY DOCUMENTS. We will include the information on the wire electroplating process shortly. - The parts of the jig to use for the wire electroplating operation are in our hands. They will be assembled as we find time. - Brian received the SEM scans for our wire from the W&M folks. He will generate a final QA report with photos and test results for all wires when he gets a chance. - We discussed the use of sticky tabs on the wire frames for HV pigtail strain relief. We may decide to use epoxy as there is much anecdotal experience with sticky tabs not adhering to their surfaces over time.
- Progress updates: * The epoxy contaminated cathode surface was successfully cleaned. This board was then scanned for surface flatness, was laminated to its ground plane, the gas window frame was attached, and the gas window was attached. All ground pigtails have been included as well. * Mark S., Roger let Armen solder several rigid-flex assemblies to sample boards and were not fully satisfied with the results. They decided to buy a stencil for applying solder paste and will use a low temperature solder with a hot air system to attach the assembly to the cathode. The stencil was laid out by Roger and passed on to Fernando for inspection. It should be out this week and arrive at JLab early next week. The low temperature solder is being pursued to reduce delamination of the cathode boards from the G10 frame during attachment. We are hoping to finalize all procedures so that soldering on "real" cathodes can take place toward the end of next week. - We had a meeting with Roger to go over proposed design changes to the cathode board. One change is to increase clearance between traces and through holes in several places. We also want to move the cut-out slot for the rigid flex assemblies and the solder points for the flex-assembly on the cathodes out by 3-4 mm to allow for increased clearance with the spacer ring. Roger and Bill will communicate more about this. It did not seem that either of these design changes would present much of a problem. - The parts for the QA system for the rigid flex assemblies were developed and we are ready to begin testing. This work will begin next week. We will test the rigid-flex assembly by itself, and then we will test the connections after soldering to the cathode. - Bill has been working on the cathode construction document building in the pictures that are being taken. The current draft of the document is located at /u/group/halld/Engineering/PRELIMINARY DOCUMENTS. We need feedback from folks involved in the process to be sure that all steps are included and accurately detailed. - Roger is pressing the Japanese company that has agreed to provide our board material. They have agreed to manufacture the material but are being non-committal on when it can be ready. - Roger needs to prepare a document for QA/stuffing/cleaning for the cathode boards and a similar document for the cathode daughter boards and ground boards.
Cooling System Tests
- Fernando is in the process of writing up the results from his cooling system studies. Stay tuned for the GlueX note. He indicated that he is back to work on this document and it should be done shortly.
Cosmic Ray Test Stand
- Beni is continuing work to setup the cosmic ray telescope and test system in EEL 126. He is making progress on reducing the noise and is working to reproduce the data from the small-scale prototype that Simon had last year. Some of his latest results will be shown in Simon's FDC status talk at next week's collaboration meeting. - We still have some mysterious behavior with the small-scale prototype response with wiggles in the X vs. Y distributions that need to be understood. Beni has reproduced this problem qualitatively and we discussed some possible causes, but more work needs to be done. - Beni has started a bench test plan for the full-scale prototype and is presently working on it after incorporating feedback. The current information is contained on the FDC wiki page under the heading "FDC test cosmic ray test stand". - The parts for the support/rotation of the full-scale prototype in the cosmic ray stand will be assembled as we have time.
- The FDC short-term work list has been posted on the FDC web site. 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.