FDC Weekly Meeting
Date: November 13, 2008
Participants: Daniel, Simon, Brian, Micah, Bill, Fernando, Mark I., Mark S., Herun, Elke, Eugene, Chuck
Next Meeting: November 20, 2008 @ 1:30 p.m.
Full-Scale Prototype Updates
- Procurements: * Roger has gotten quotes from Allflex on the rigid-flex assembly order. He will pass the cathode daughter board drawings to Fernando for final inspection. The PR for these boards (for the qualification run) should be ready in a couple of days. Roger will hold off on order the ground rigid-flex assembly boards in the first round. * Roger should communicate the board stuffing needs with Kim and she can arrange for the work in-house. * Mark S. and Brian have been working to test the sense wire spool that arrive two weeks ago. They have prepared samples for the SEM checks and have done some strength tests following the outline in our wire specification document. Mark S. and/or Brian will prepare a baseline report for comparison with all future orders. * As it was not clear if the contract depended on our qualification tests, Brian will follow up with the procurement folks to find out. We definitely need our qualification tests built into the order. * The order for the field wire just arrived and Mark S. and Brian will start on the qualification checks. * G10 ring order status: * No new news. Expected delivery date is roughly 3 weeks. * 110IG Rohacell order status: * No new news. Expected delivery date is Dec. 17. - Mark S. has taken responsibility for watching over the FDC component stores and keeping the database up to date. - Bill is working to put the local HV connectors selected by Fernando into the 3D CAD model and to detail how they will be attached (as they are quite massive). Bill will get back to this work when he has a chance. - Brian and Bill will send their procurement information for the full-scale prototype to Mark S. who will update the excel file. * Location: M Drive/halld/Electronics, or for more sophisticated folks, /u/group/halld/Electronics. * Folks should fill it out in the given format.
Wire Frame Construction
- We have settled on a thickness tolerance for the wire frame of 8 mils to match the thickness tolerance for the cathode frames. DSC and Bill are working to complete a specification/tolerance document for the wire frames for circulation. - Mark S. has done quite a bit of prototyping with the wire frame construction during the past week. This includes finalizing the tooling and assembly procedures for laminating the print circuit board ring, studying epoxy seepage through the circuit board holes, making the G10/foam laminate. All tests were very successful and it looks like all procedures are now essentially final. We still need to very that the JLab machine shop can mill the G10/foam laminate to the tolerances that they quoted us. - Mark S. and Brian are presently using the clamp bar assembly designed by Bill to lay up the first print circuit board annulus. After this is fully inspected and vetted, they will proceed to make up the remaining three annuli. The 4 rings will be wrapped and stored away until they are needed. - Mark S. will modify the wire frame construction procedures document after things are a bit further along. He will take photographs of the necessary tools. - We think we have a signed Phase 2 contract in place with IUCF, but we have not received final word from either end.
- DSC has put together a modified R&D plan for the cathodes. Chuck is putting this into FastTrack now and it will be circulated shortly. Folks should look this schedule over carefully, especially those areas where your name is listed. Brian will be responsible for defending the progress on this plan, including all work done, delays encountered, successes, etc. He will work with DSC to keep the schedule up to date. He will defend the work timeline at each FDC meeting. - The specification/tolerance document for the cathode frames is being worked on. It will be circulated shortly. - Mark S. checked on the cathode boards in the storage box and they have not disintegrated. He will also regularly check the pressure in the dewar and replace it when necessary. - Fernando reported on the additional SEM studies of the dark spots that were on the cathode prototype board from Allflex. The dark spots are most likely copper oxide. There is still not a great answer as to why they seem to have a higher resistivity. We could study how the spots charge up in the SEM, but may delay this as it is not a major issue now, just a point of curiosity. - Bill has nearly completed the design of the cathode edge cutting system. He will need another week to complete the fabrication drawings and then the procurement will begin. More to come. - Cathode flatness measuring system: * Micah has completed a scan of the granite table surface and it looks like there is a misalignment problem with the system at the level of 1 mm across the table surface. Bill will look into this and make adjustments. Whatever system problems remain can be used as a baseline measurement that can be subtracted from the measurements for the cathodes. * Micah has measured the high tension cathode in one orientation, but has not accounted for the misalignment issues yet. More to come. - Still waiting on an updated version of the cathode construction document. Bill has this now and will get back to it soon. - Mark S. and Brian have done some studies of making their own Kapton tape for joining the cathode panels. Earlier prototypes look good, but studies are still in progress. They are laying up three panels of our dummy cathodes presently. They will then move on to do some load testing. Eugene will help out with the tension measurements. - Bill laid out an idea that he had for connecting the external ground to the cathodes. He will discuss this further with Mark S. and have him put together a prototype or two to see if it works. More to come.
- Bill reported that we have a sheet of polyethylene and a sheet of polypropylene. The blueprint for construction of the space frame is ready for submission to the JLab machine shop. - Bill is in the process of evaluating two adhesives for attaching this frame directly to the cathode boards. This will eliminate one o-ring groove on these spacers. More to come.
Stack Assembly Procedures
- DSC, Brian, and Bill will work to finalize the stack assembly construction document that has been prepared. This document should be in place before we get too far in the construction process. - Bill has found some plastic threaded rods that could be used to compress the stack. We will be receiving some samples shortly and will carry out some loading tests.
Cooling System Tests
- Fernando is in the process of writing up the results from his cooling system studies. Stay tuned for the GlueX note. - Bill has done some ANSYS modeling to better study the connector that goes from the daughter board card to the cooling loop. These will be added to Fernando's note.
Gas System Design
- Slava has worked on a preliminary layout of the gas handling system for the CDC and FDC. He provided two options for the FDC system design that were essentially a basic version and a fancier version. Slava's design work was based on the original concept that Brian came up with long ago. We will continue the design work as we have time.
- 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. - Kim has provided a draft of a procedures document for the Phase 1 and Phase 2 wire frame PCB component attachment. She has merged this document with Fernando's cleaning and handling document. The document is being finalized with some additional language on soldering iron temperature vs. time profiles. It should be completed before the start of the Phase 2 component soldering.
- ASIC specifications for the dynamic range have now been completed for both the CDC and FDC. Fernando is now communicating all details to Mitch Newcomer to finalize the design before submission. The hope is to have submission for the beginning of December. If we are not ready by then, the submission will slip into 2009. - We still have the lingering issue of the problematic x-y plots from the 2-micron Cu cathodes. Simon looked at data that was collected and remade the picket fence plots. Details are given in the FDC Log Book. Using a better pulser calibration run, he managed to remove the lion's share of the wiggles, but they are still there at a lower level. More thought is needed on this.
- 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.