Minutes-2-5-2009
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FDC Weekly Meeting
Date: February 5, 2009
Participants: Daniel, Simon, Brian, Mark I., Mark S., Bill, Beni, Fernando, Roger, Eugene, Chuck
Next Meeting: February 12, 2009 @ 1:30 p.m.
Contents
Full-Scale Prototype Updates
- Elke raised the issue of signed drawings for the FDC prototype. After the
engineering meeting it seems that this will not be required in the short
term after all due to the manpower burden. If there are any changes in
thought on this, we will revisit the issue.
- Procurements:
* The small order of rigid-flex assemblies arrived and Roger certified
that they looked good. He had his techs solder one of these assemblies
to a prototype cathode daughter board. This all looks very good. The
remainder of the order for all the required boards for the full-scale
prototype is on hold as it does not need to go out until all space
and clearance issues are hammered out.
* The replacement order for the Rohacell arrived. Mark checked all the
pieces and they were all within spec. The old, problematic Rohacell has
been marked with red ink and the new, good Rohacell has been marked with
green ink. Mark will send some of the pieces of the original order back
to the company so that they can look into the problems.
* We want the remainder of the cathode order to go out by the end of this
month. This sets the time frame for the redesign work Roger is doing.
The plan is nominally to order 6 more full sets of 2 micron boards and
2 full sets of 5 micron boards. If there is money available, it would
not be bad to order a couple more sets of 2 micron boards as we will need
several for R&D work.
- Chamber Wire:
* Brian has provided samples of our sense and field wires to the SEM folks,
they will complete the mass spectroscopy analysis. As we have not heard
anything for a while, Brian will check in with them.
* Brian will prepare a final QA report with photos and test results
for all wires when all studies are complete.
* A PR has been prepared for a combined Hall B/Hall D wire order for
construction. The PR is not yet funded. Coupling the PR should save
a few dollars and make QA checking based on the same QA specs easier.
- 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.
- The Hall A folks have inquired about use of the clean tent. DSC talked with
Bogdan Wojtsekhowski. We will known much better next week when we can let
them have access. We will not be able to given them all the time they need
in one shot, but that is O.K. according to Bogdan. As they will use our
granite table, we will put a protective cover on it so that it will need
need extra cleaning.
- 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.
Wire Frame Construction
- The four wire frames were finished last week and shipped to IUCF. They were received at IUCF on Friday and were reported to have arrived in good condition. - DSC is working with Keith to set up regular meetings on progress and to define JLab sign-off points before work can continue at IUCF. DSC and Keith may have the first progress meeting tomorrow to go over work setup this week. - 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. - Kim has completed a new version of the wire frame PCB stuffing document. DSC will review it and post it with our other FDC procedures documents. - Bill has designed a wire frame protective cover that will be in place during the Phase 2 component stuffing. This cover is in the shop now being machined and will be done shortly. We may 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.
Cathode Planning
- 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:
* The cathode edge cutting system is now under test. The system seems to
work well. A couple of issues are presenting themselves that we are
working on. One is to position the cathode board without introducing
distortions in it due to static coupling to the granite table surface.
Also, we are trying to rig up a camera to allow us to easily view the
position of the cutting head relative to the edge of the strip along
the full length of the board. A few small pieces are in the machine
shop and work will continue next week. Hopefully we will be far enough
along to test cut one set of the 5 micron "real" boards next week.
* No progress on completing the cathode construction document. Stay
tuned.
* New G10/foam laminates were made up for the cathode boards for the
cathode sandwich prototype. They are in the machine shop now waiting
to be milled to their required thickness. We are in the queue. Once
his work is done, we will make up the prototype cathode sandwich.
* Brian has prepared one "cathode" layup using two pieces of blank
Kapton. This cathode mockup has been attached to the transfer ring and
is sitting in the tensioning fixture now. Some problems were found
setting the tension due to limitations of the fixture, but with the
addition of a few springs, we will get around this tomorrow or Monday.
The tension will be set to 500 N/m as a starting point.
* A second cathode layup will be prepared tomorrow using 3 pieces of
blank Kapton. These pieces will be cut using the edge-cutting system.
* Roger has completed modifications for one of the three cathode panels
to allow for stretching perpendicular to the strips of up to 4 or 5 mm
and parallel to the strips of 2 to 3 mm. He sees no problems modifying
the other two boards.
* The remainder of the cathode order should go out by the end of this
month.
* We discussed plans for using an optical system to measure the
cathode board distortions after they have been tensioned. Presumably
we could use the horizontal mill in the machine shop using their
camera system. This will most likely be needed in about 6 weeks.
* The clearance issue that Bill raised at our last meeting between the
cathode daughter boards between neighboring layers in the middle of the
cathode sandwich can be solved by flipping the artwork on the cathode
daughter board cards. Bill has verified this will work for all clearance
issues. Roger will go ahead and make the necessary changes.
* We had discussed the possibility of making a separate mechanical mockup
of the cathode sandwich so that we could get a better feeling for the
available room and potential clearance issues. Remember that we need to
be able to have access to plug and unplug the preamp cards and the preamp
power cables. As the mechanical cathode sandwich will be ready soon
enough, we will use this to play these space study games.
* We have been worried about the mechanical strength of our cathode frames
and discussed that we may have less of an issue if we were to make up the
cathode frame sandwich (with ground plane) first before attaching the
cathode skins. We decided to hold off on such a plan until we study the
prototype frames being made up at present.
* Brian will pursue ordering a roll of 12.7 micron aluminized mylar for our
ground plane material. All we have on hand at present is 6.3 micron
material.
* We will need to place an order soon for more G10 annuli for the cathode
frames (the larger pieces). Bill will put together a PR shortly after
Mark checks our inventory. This is confusing as we should have ordered
all of the necessary G10 stock with our last order in December.
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.
Spacer Design
- The spacer frames are now under construction in the JLab machine shop.
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.
Documentation
- 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.
Small-Scale Prototype
- We will be moving the FDC cosmic ray test stand from the Test Lab back to the EEL building. This move should be completed in the next 6 months or so.
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.
