FDC Weekly Meeting
Date: February 19, 2009
Participants: Daniel, Brian, Mark S., Bill, Chuck, Roger, Beni, Mark I., Elke, Eugene, Fernando, Simon
Next Meeting: February 26, 2009 @ 1:30 p.m.
Full-Scale Prototype Updates
- Clean Room Issues: * The Hall A folks have been given the clean tent to use until Monday morning. We will let them know then if when we need it back. * The refurbishment of the EEL clean room is in the planning stage. There have been rumors that it could start in April. Elke will continue to communicate our needs to the management so that our plans are considered in all of this. - Cathode Board Redesign: * Roger is continuing work on the cathode board redesign to allow for the board stretching. He should be ready to circulate drawings shortly so that we have a hope of getting this order out the door in the next couple of weeks. Folks should look the drawings over to be sure that all necessary alignment artwork is present. * Roger has a new version of the cathode daughter board with the power connector flipped to the other side. He will circulate drawings to Fernando and Bill for study. - Chamber Wire: * Brian has not yet made contact with the SEM folks. He has tried but could not reach anyone. He will continue to pursue them. * Brian will prepare a final QA report with photos and test results for all wires when all studies are complete. - Mark S. is also responsible for upkeep of the list of procurements for the full-scale prototypes. * Location: M Drive/halld/Electronics, or for more sophisticated folks, /u/group/halld/Electronics. - A bottle neck in our prototype construction is that we have only one cathode board tranfer ring. Bill will prepare a drawing for the shop and work to have a second frame constructed. - Procurements: * Fernando discussed a proposal to purchase HV modules, HV cables, and HV connectors for the prototype. We discussed ways to proceed with placing this order under the aegis of ordering parts for the final detector. Offline discussions will continue on how to proceed. - Calibrations: * Fernando brought up the issue of gain calibrations due to component tolerances on the ASICS and the calibration circuitry. Details of the issues are contained in GlueX-doc-1185. It appears that to do better than 10% on the channel-to-channel gain calibrations we will have to characterize each daughter board card and keep track of it in a calibration database. More to come.
Wire Frame Update
- We had a teleconference with IUCF on Tuesday to get an update on their status working on Phase 2. We will arrange for another tomorrow. At this point they should be ready to wind the wires for the first two planes. More details on this conference to come, stay tuned. - Nominally Bill will go to IUCF for the week of March 16. If this moves up, IUCF will give us a heads up so plans can be made. - To remove the problem with glue wicking up through the vias in the PC boards, we have asked Kim to reduce the size of the vias (to eliminate the openings) and to cover the vias with the solder mask material. - Bill has designed a wire frame protective cover that will be in place during the Phase 2 component stuffing. It needs to be test fitted onto our existing wire frame to be sure all is good in the world. Bill will also design a turntable for the solder technicians to use with the wire frame for this task. - Mark will update the wire frame construction document based on lessons learned from the prototype frames. A new version will be posted when his work is done. - We plan on performing the electroplating technique with at least a couple of our full-scale prototype wire planes. We will do some more practice on the Phase 1 winding planes to finalize the technique and to prepare a procedures document. A positioning jig will be put together to allow for precision positioning of the deadened region and its size. We will plan on doing optical scans of the plated region to be sure the plated region is very smooth and well defined. - To be compatible with the HV connectors that Fernando has selected, we will most likely have to modify the granularity of the HV connections on the HVTBs. We will reduce the number of connections on each HVTB from 6 to 4. More thinking on the split remains to be done.
- We reviewed the cathode R&D timeline. Folks are reminded to pass on progress updates to Chuck every Wednesday. The current schedule is being kept on the mdrive at: * Location: M:\halld\Individual-Schedules\FDC or for more sophisticated folks, /u/group/halld/Individual-Schedules/FDC - Progress updates: * No major progress has been made with the cathode edge cutter while we await pieces from the shop to hold our viewing camera. By next week Bill believes the system will be complete and all test cuts done and studied. We should be able to cut "real" cathodes by next week. * No progress on completing the cathode construction document. Stay tuned. * We have made one cathode frame up using a two-piece bare Kapton "cathode" panel. It was tensioned to 500 N/m. There were significant distortions and pringling of the board, but it held the mechanical load without cracking or breaking. The distortions were significant though. Bill is laying out a transfer jig to keep the cathode frame flat as it is transferred from the tensioning jig to the construction jig. We want to ensure the cathode frame remains flat to ~1/16 in to protect the frame and the cathode boards. * A second cathode frame is now being put together using a three-piece bare Kapton "cathode" panel (whose pieces were cut with the edge cutter). This will be tensioned to 500 N/m. After this is removed from the tensioning system, we will tension an aluminized mylar ground plane and then put our mechanical mock-up cathode sandwich prototype together. With this prototype we will configure our external ground connections to the cathode planes and the ground plane. If everything works out, we should be able to claim that we have an essentially final design for our cathode frames. This would be a major step forward in the FDC design. * Bill surmised that we might be ready to start construction of a cathode frame prototype using our "real" 5 micron Cu boards by the end of next week. * Brian has tried to find a roll of 12.7 micron aluminized mylar for our ground plane material but is not having luck so far. All we have on hand at present is 6.3 micron material and we will use this in the mechanical cathode sandwich prototype.
Cathode flatness measuring system
- Documentation of the system continues. See the FDC wiki page for details. - Brian has completed a PR for a second laser for the FDC work.
- The spacer frames are now under construction in the JLab machine shop. They should be in our possession very shortly.
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.
- 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.
Cosmic Ray Test Stand
- We will be moving the FDC cosmic ray test stand from the Test Lab back to the EEL building. This move should be probably take place in April. - 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. - We would like to put together a bench test plan for the full-scale prototype within the next couple of weeks. This preliminary test plan will be used to provide information on what test stand fixtures to support the chamber we will require. Bill can then work on the design and get things prepared in the shop. Also, we would like to layout a design for the electronics before too much longer so that we can reduce time from when the full-scale prototype is constructed to when we get into the test plan.
- 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.