Minutes-11-20-2008
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FDC Weekly Meeting
Date: November 20, 2008
Participants: Daniel, Simon, Brian, Mark S., Elke, Herun, Micah, Fernando, Curtis, Kim, David, Eugene, Chuck, Mark I., Jim, Beni
Next Meeting: December 4, 2008 @ 1:30 p.m.
Contents
General
- 16 folks attended today's meeting. This is a new record.
Full-Scale Prototype Updates
- Procurements:
* Rigid-flex assemblies:
* Fernando is looking over the design drawings made by Roger. The
plan is to move forward with a PR for a small number of boards
this week. The lead time is about 3 weeks, so the boards might
arrive before the end of the year if the stars line up.
* Roger will pass on board stuffing details to Kim. She will then
serve as our contact with Greg Arnold's group.
* The plan is to submit the remainder of the order for the full-scale
prototype in the first quarter of next year.
* Wire QA studies:
* The QA checks for the sense wires are complete.
* Brian and Mark S. are gearing up to prepare a slide for the SEM
studies of the field wire. They will also perform the mechanical
tests for wire strength of the field wires.
* Brian will check with the purchasing agent responsible for the
wire order to find out what QA qualifications were part of this
order if any. If they were not in place, they will need to be for
future orders.
* Mark S. will prepare a QA report with measurement data and photos
for the wire. This will serve as our baseline wire qualification
document. The results of all future wire spools will be compared
to this data.
* G10 ring order status:
* No new news. Expected delivery date is roughly 2 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.
- 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.
- 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.
Wire Frame Construction
- DSC and Bill are working to complete a specification/tolerance document for the wire frames for circulation. - Mark S. and Brian used the clamp bar assembly designed by Bill to lay up the first print circuit board annulus. The operation worked well in some respects, but height measurements along the lap joint seams revealed variations at the level of 10 to 20 mils. The reasons for these problems have been understood (we think) and they will be ameliorated (nice word huh) before layup of annulus #2. - Mark S. and Brian believe that they should be able to complete laying up the remaining two PCB annuli next week before the Thanksgiving holiday. - 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.
Cathode Planning
- We reviewed the cathode R&D timeline. The plan is that on Wednesday,
Brian will pass along work completion percentages on each task to
Chuck. Chuck will then update the timeline for the FDC meeting and then
we will review the schedule carefully at each meeting. This makes for
proper project management and will allow us to keep track of progress
more closely.
- The current version of the schedule is on the mdrive at:
/u/group/halld/Individual-Schedules/FDC
- The specification/tolerance document for the cathode frames is being worked
on. It will be circulated shortly.
- 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:
* It was verified that the problems seen in the scan data presented
last week by Micah were due to rail misalignment problems. We
agreed that if the job is very simple, we can shim the rail and
then rescan the granite table. If the job would take too long, we
can deal with what we have. This is true as the granite table
measurement is a baseline and can be subtracted from all data.
* David and Micah impressed the heck out of us with some recent scan
analysis work. See the FDC wiki for details. In short they
lined up the surface defects in the granite table surface with the
measurement data and showed us some new details on the flatness scan
of the high tension cathode.
* Micah and David are working on documentation for the system to
provide full instructions for operation and data analysis. Mark S.
will take over as the system expert and Micah will transfer knowledge
to him.
* Micah and Mark S. will be responsible for completing the measurements
on the high tension cathode as a function of rotation angle.
- Still waiting on an updated version of the cathode construction document.
Bill has this now and will get back to it soon.
- Brian and Mark S. have made up a new cathode prototype using the 5 micron
Cu dummy boards. This prototype was built for several reasons:
* To remind folks of how to make the cathodes seeing that one has not
been built for some time.
* To test out the new glue strips. Two-inch wide Kapton strips painted
with high strength hysol adhesive using the foam rollers. The technique
worked beautifully and the epoxy stayed where it was supposed to.
* To set up a system to measure the cathode tension in the tensioning
system. Brian rigged up a bar to support the laser head over the
center of the cathode. With the help of Eugene that measured the
tension in situ. The problem is that measurements of the tension at
the center of the cathode and offset from the center due not give the
same answer (by alot). Eugene believes that this could be due to the
weight chosen (a ring about 6 to 8 inches in diameter). More work
will be done tomorrow.
* The cathode was tensioned up to roughly 1000 N/m and the seams held
perfectly. The new glue strip technology seems to be a success.
* Brian will leave the cathode at high tension for the next several
weeks to make sure that there are no problems with creep.
- 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.
- Herun gave a presentation on work that she had been doing with the
ANSYS program to study deformations in the FDC wires and cathodes. Her
deformation talk has been placed on the FDC web page for viewing.
Spacer Design
- 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.
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. - 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.
Small-Scale Prototype
- 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.
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.
