Minutes-8-20-2009
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FDC Weekly Meeting
Date: August 20, 2009
Participants: Daniel, Simon, Beni, Brian, Bill, Mark S.
Next Meeting: August 27, 2009 @ 1:30 p.m.
Contents |
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General Construction Updates
- Stephen Burnett from Hall B will be providing technical assistance to FDC prototype construction work for the next couple of months. He will begin with us for a significant portion of this time starting on Monday. - Brian will be off of the FDC project for most of October. This schedule should be fine if we can complete detector construction by the end of September, which is what we are presently expecting. - Mark S. has completed the emergency solenoid work from last week and is back to his normal work level for the FDC. - The parts for the assembly jig on which the detector stack will be constructed will be put together as there is time. - Bill has begun work on the FDC stack assembly document. The draft will be made available after he completes a bit more work on it. The document will be fleshed out during the assembly process with relevant photographs. He expects to have a draft available shortly as he has made significant progress on it. - The composite frames for the two gas windows have been completed. Sealing of the I.D. and O.D. of the frames has been completed, with the sealing of the bolt holes remaining. The tensioning of the gas windows and the lamination to the composite rings will begin next week. Due to the stresses on the gas window frames (with the tensioned gas window attached), Bill wants them attached to their corresponding cathode frames just after they are prepared. The plan is that the gas windows will be laminated to the end cathode planes.
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Wire Frame Update
- Mark S. will go through Rich's notes to provide information on the problematic wire frame HV busses so that we can know where things were during their last tests. What is needed is a list of frame number, bus number, and current draw. - One of the wire frames has been sitting in the tent for several weeks now and still needs to have HV checks completed. No work has been completed on this but it needs to get done as the wire planes are soon to become our construction bottleneck. Brian and Beni will work on this starting on Tuesday of next week. Based on the results obtained, we will then make a plan on how to proceed to diagnose the high current problems seen on several of the HV busses. - The last wire plane that needs checking and repairs is P1. This work will not happen in the short term as only 3 frames are needed for the full-scale prototype and we don't have the manpower to work on this now. Three of the frames have been cleaned and had wire repairs done. - We were worried about torques applied to the preamp card associated with the cooling loops. We will most likely improve the bonding strength to the wire frame by adding epoxy around the perimeter. We will investigate this when we get a bit further in prototype assembly. - 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. He will include the information on the wire electroplating process as well. - 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.
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Cathode Update
- Progress updates:
* Bill has all safety work in place to remove the epoxy from the
contaminated cathode. This work will begin shortly. We are presently
planning to use this cathode in the full-scale prototype.
* Flatness measurements for the two cathode boards for the second
cathode sandwich have been completed and are in spec. There does
seem to be some sort of systematic problem at the 20 micron level
that always shows up on the left side of the flatness scan. Bill
will look into this.
* The first cathode sandwich is done up to the point of attaching
the rigid-flex assemblies.
* The two cathodes for the second cathode sandwich will be laminated
together today. It will then be ready for soldering of the rigid-flex
assemblies. We have simplified the design for the ground tab
attachment for the cathode that the ground plane was laminated to.
This reduced the number of pigtails by six.
- The end cathodes will need to have their ground planes attached. These
mylar planes will have holes added to them to keep the differential gas
pressure at zero. Work will begin on make some test holes before working
on tensioning the full-scale foils next week.
- We will be investigating strain relief design for the ground pigtails to
be sure that they cannot be over stressed and ripped off.
- Rigid-flex assembly electrical QA status is unknown. Mark S. will check with
Armen Stepanyan. We expect Fernando to be back to work at JLab next week
to follow up.
- Mark S. will begin test soldering of the rigid-flex assemblies to
test cathode pieces to finalize the soldering procedures. He will work
under the direction of Roger and Fernando. As this project is another
bottleneck in the completion of the prototype, we are eager to get started
to understand the schedule for completing this work.
- Bill would like some additional design work done on the cathodes to give
more space between traces and holes. He sketched out his concerns, but we
will need to have a separate meeting with Roger to find a solution.
- 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.
- We are standing by waiting for information on the PR for the 2-um board
material.
- 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.
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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.
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Cosmic Ray Test Stand
- Beni is continuing work to setup the cosmic ray telescope and test system in EEL 126. He is now battling a noise source somewhere broadcasting at about 30 kHz. He has also found some isolation transformers to give him some clean power sources. It looks like one important source of noise (among several) is the CAEN HV supply that we are using for the hodoscope scintillators. - Beni has been working to reproduce Simon's picket fence plot for the small-scale prototype and has made some good progress. Presently his is chasing down some potential problem with the gas and will work to verify the gas mixture. - 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 is now trying to reproduce the "picket fence" plots from the small-scale prototype to get back to where Simon was last year. He is getting close. - 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.
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Work List
- 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.
