FDC Weekly Meeting
Date: October 22, 2009
Participants: Daniel, Beni, Bill, Simon, Fernando, Mark S., Mark I., Casey, Eugene, Glenn
Next Meeting: October 29, 2009 @ 10:00 a.m.
- Next week the technicians will be at crane training at the end of the week. Hopefully the physicists will be busy going through the test plan for studying the single layer prototype detector. - Next week's meeting time will be at 10:00 a.m. due to schedule conflicts with interviews.
General Construction Updates
- Tom Carstens and crew completed the reassembly of the clean tent in EEL 126 and we have reorganized the room a bit. Lots of activity and progress occurred very quickly. The space is now being fully utilized for construction of the full-scale prototype. With the clean tent running for several days, a device to measure the cleanliness of the tent recorded particle counts of less than 1000 per cubic foot (of size greater than 0.5 microns). Looking at the floor, you wouldn't have guessed this. - Stack assembly for the single-layer prototype is in progress. The wire frame P1 has been laminated to its associated cathode/gas window frame and placed onto the stack assembly jig. We have to attach the HV pigtails for P1 and then install the gas spacer ring and the second cathode/gas window frame. We will be working on leak checking using an argon-sensitive gas sniffer using an argon/CO2 gas mixture inside the prototype. This work should begin tomorrow. All rigid-flex assemblies have been included on the two single cathodes that include the gas windows, and associated electrical QA has been completed. - We are finalizing the grounding configuration for the single-layer prototype. We will use two new preamplifier cards, four old preamplifier cards (used with the small-scale prototype), and some temporary grounding cards that Fernando has prepared. Fernando will provide a list of signal, HV, and grounding cables to Mark S. to be made over the next couple of days. Fernando's temporary ground boards will be ready by Wednesday of next week. - The preliminary FDC stack assembly document draft is located at: /u/group/halld/Engineering/PRELIMINARY DOCUMENTS. The document will be fleshed out during the assembly procedure for the full-scale prototype.
Wire Frame Update
- Wire frame P1 has successfully passed all electrical QA checkout and its LV and preamp card connectors were fortified with epoxy. Frame P1 was laminated to its associated cathode frame (the screwed up cathode with the gas window). - Wire frame P4 has undergone a preliminary electrical QA check and has a few problems that need to be addressed. Wire frame P3 will then follow. - 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. - 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. - Kim has verified that she will be available in December to complete the wire board redesign work.
- Progress updates: * All rigid-flex assemblies have gone through QA and been delivered for attachment to our cathodes. * We do not have enough rigid-flex assemblies due to yield losses on the original order of 60 (54 are needed for the prototype). An order for another 2 dozen pieces was supposed to go out last week but apparently did not. DSC will follow up with Roger after the meeting. * Rigid-flex soldering update: The two single cathodes are now fully populated with rigid-flex assemblies. Casey has completed work on another cathode that is part of a cathode sandwich. He is ready to flip the sandwich over and proceed on the other cathode. - The current draft of the cathode construction document is located at: /u/group/halld/Engineering/PRELIMINARY DOCUMENTS. - 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. - Roger has verified that he will be available in December to complete the cathode board redesign work.
- Fernando has certified the lastest ASIC preamplifiers as meeting our design specifications. See GlueX-doc-1364 (The Gas-II/GPC-II GlueX Preamp Card Preliminary Test Results) for details and results. Fernando will make one anode board and one cathode board available for the single layer tests next week.
- Bill raised an intriguing idea for simplified the rigid-flex and cathode design. We agreed it might be something that will simplify the design, reduce costs, and make the soldering work easier. As there were some issue to hash out, we decided to take this offline and continue the discussions. The basic idea Bill had was to fold the cathode board through the slot on the frame and to solder the flex assembly to it on the back side. This would eliminate cutting pockets into the back of the wire frame and allow us to increase the trace spacing on the cathode for soldering to the rigid-flex assembly. More to come.
Cosmic Ray Test Stand
- Beni has been investigating the wiggles seen in the reconstructed wire position from the cathodes. We focussed on log entry 419 in the FDC logbook. We believe that the periodicity seen is due to the algorithm Beni is using to determine the U and V centroids. He will talk to Simon and get his parametric form to see if this addresses the problems.
- 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.