Minutes-12-4-2008
From GlueXWiki
FDC Weekly Meeting
Date: December 4, 2008
Participants: Daniel, Simon, Brian, Bill, Mark S., Micah, Herun, Mark I., Chuck, Roger, Beni, David, Fernando, Jim
Next Meeting: December 11, 2008 @ 1:30 p.m.
Contents
Full-Scale Prototype Updates
- Procurements:
* Rigid-flex assemblies:
* Fernando and Roger have not yet converged on review/approval of
the design drawings. The plan (like it was at our last meeting)
to move forward with a PR for a small number of boards in the
next couple of days. The lead time is about 3 weeks, so the
boards will not be in our hands this calendar year. DSC stressed
the importance of completing this order and getting the main
order out the door as soon as we can.
* Roger has passed on the board stuffing details to Kim and she
has communicated with Greg Arnold's group.
* Wire QA studies:
* The QA checks for the sense wires are complete.
* Brian has prepared a slide for the SEM studies of the field wire
and given it to the SEM folks. They will complete their work in
about a week. The mechanical load studies of the field wires were
done and the wire passed (barely).
* Brian will prepare a final QA report with photos and test results
for all wires in the next week.
* Brian checked with the purchasing agent responsible for the
wire order to find out what QA qualifications were part of this
order if any. Apparently they were not part of the order. It is
not clear what happened. Was this a miscommunication or a did
somebody drop the ball?
* G10 ring order status:
* No new news. Expected delivery date is roughly 1 week.
* 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
- Bill has completed a draft of a specification/tolerance document for the wire frames and we discussed it. Presently the final tolerance is given as a linear sum of the different sources of uncertainty. It is more likely relevant to quote the quadrature sum. - Mark S. and Brian have completed assembly of the 4 PCB annuli. This included all touch up work and cleaning. The board rings were placed in the plexiglas storage box for safety. - Bill has worked with the JLab machine shop to do some tests of the system to do vacuum bagging on the G10/foam laminate. While things did not work fully has Bill had hoped, he declared that we are ready for preparation of the G10/foam laminates once the orders arrive. Bill has already provided the drawing for the foam cutting template to the machine shop (remember that we will be piecing together our foam cores from several arcs). - Bill has communicated with the machine shop about the machining requirements of our G10/foam laminates. DSC has a remaining question on whether any machining is needed on the wire frames after assembly. We should be able to get this work through the machine shop relatively quickly. - Mark S. is working to modify the wire frame construction procedures document including the photographs that he took. A new draft has been passed around to Bill and Brian for feedback. A draft will be given to DSC shortly for review. - DSC talked to Keith at IUCF with regard to the unofficial schedule for winding. It looks like we should be able to get the wire frames to IUCF by the middle of January if our current schedule holds up. - 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.
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
- Bill has completed a draft of a specification/tolerance document
for the cathode frames and we discussed it. Presently the final tolerance
is given as a linear sum of the different sources of uncertainty. It is
more likely relevant to quote the quadrature sum.
- Bill has completed the design of the cathode edge cutting system. He is
finalizing the fabrication drawings and then the procurement will begin.
Some of the parts actually have already been ordered and delivered to
JLab. After assembly of the system, we will work through a full test
plan before cutting any of our "real" cathodes.
- 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. The rail
was reset and the granite table surface rescanned. It seems that a
rail misalignment still remains, although at about half the level
it was at before.
* Bill arranged for the Survey Group to survey the flatness of the
granite table (to separate problems with the table surface from
rail misalignment issues). The work will be completed by the end
of the day today. The survey data will then be passed along to Bill.
* David showed us comparisons of table scans before and after resetting
the rails. See the FDC wiki for details.
* 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. This
work should be completed in the next week.
- 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. Eugene has completed his tension measurements and
has placed his results on his web site.
The measurements demonstrate a systematic dependence of the result on
the radius of about 4%. The measurements with different weights are
consistent within 1%, apart from one point, which must be an error of
the particular measurement (the laser moved?). The foil elongation
perpendicular to the strips was measured to be about 0.33% for the
1-mil Kapton with 5-micron Cu at about 1300 N/m.
* Brian has attached the cathode to a G10 ring and will leave it for the
next several weeks to make sure that there are no problems with creep.
* Bill is still working on the design for the system to hold the laser
head and allow movement for measurements at several locations. It is
presently not clear if this is a necessity. DSC willl talk to Eugene.
* Brian has been asked to come up with a detailed list of remaining
prototypes that need to be made before we can consider making up a
cathode from our "full-scale prototype lot".
- We will use the sample board from Allflex (2-micron Cu) for performing
some handling studies. We will then use it to measure the stretching of
the foil at the nominal cathode tension to compre the properties of
Espinex-m to Kapton.
- Mark S. made up several prototypes of a scheme to connect the cathode
boards to the external ground. Folks should look these over from the
standpoint of mechanical and electrical connections and give feedback.
Spacer Design
- Bill has declared that the spacer ring will have two o-ring grooves. This is the best solution (and most viable). He will move to have the machine shop prepare the polyethylene and poly propylene rings. These will be complete spacers, and thus, will include the o-ring grooves and the gas plumbing.
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.
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.
