Minutes-9-11-2008
From GlueXWiki
FDC Weekly Meeting
Date: September 11, 2008
Participants: Daniel, Simon, Fernando, Mark S., Kim, Eugene, Bill, Micah, Herun, Jim, Beni, Elke
Next Meeting: September 25, 2008 @ 1:30 p.m.
Contents
Announcements
- Simon will be giving the FDC report at the collaboration meeting next week. He will circulate his slides shortly for feedback. - The FDC DOE report is due by the end of this month. The report will be on the prototype wire winding from Phase 1. Elke will provide DSC with an exact title and a template document in something called "word"? DSC is suspicious that Elke was speaking in German and really meant LaTeX. DSC will work to complete the report in the next week or so and circulate it for feedback.
Full-Scale Prototype Updates
- Clean Room:
* Brian is working to put our clean room/tent together. He has gathered
sticky mats, gowns, hats, gloves, shoe covers, cleaning equipment,
trash cans, etc.. He has ordered a few things such as sticky rollers
to clean the area that will arrive soon. He will get a bench and a
storage closet soon.
* Brian and I are now finalizing a procedure for entering into and
leaving the clean space that we will all have to follow. After this
procedure is finalized, we will all meet at the clean tent have a
walkthrough of everything. As of now, we will be following full clean
room procedures in the tent.
* The clean tent power and clean tent itself have been loaned for
use to Jack Segal and the HD-Ice folks for the next week while we
wait for our cathodes to show up.
- Procurements:
* Roger has not finished the design work for the cathode rigid-flex
assemblies. As he is away for the rest of the month and Kim isn't
fully comfortable finishing the design, we have decided to put things
on hold until Roger returns. The final number of these boards (roughly
70) has yet to be finalized.
* Elke asked us to prepare a spreadsheet listing all expenditures for the
full-scale prototype. Kim has started to prepare this including all
of her procurements (including those through Fernando) and those of
Bill. She still needs input from Brian, Roger, Lorelei, Simon, and
anyone else who has order parts n' pieces. We will post a draft of
this spreadsheet in an accessible place shortly.
* Brian is working on the procurement of the sense and field wires
for the full-scale prototype. DSC has prepared two documents for our
wires: Wire Specifications Document and Wire Testing Document.
These documents have been passed on to the wire suppliers. More
discussion on this when Brian returns. These documents are posted on
the FDC procedures web page.
- Fernando has considered how we will make the connections from the HVTBs
to the power supplies. He has identified a connector that will connect
to the baby cables soldered to the HVTB and the cables that go to the
power supply. Bill is working to put the connectors into the 3D CAD
model and to detail how they will be attached (as they are quite massive).
Once we get some of these details worked out, we will discuss when we
want to place the order.
- Brian identified a group that can do our SEM wire studies (the W&M group).
Brian brought them our already prepared sample from our earlier SEM tests
to see if they were content with our slide. They were not and redid the
slide and then performed some scans. Eugene showed a sample of SEM
pictures that showed the wires were quite dirty (likely dust particles).
However, one picture showed a wire sliver coming off the sample. We have
no idea what this was. The picture that Eugene showed have been placed on
the FDC web page in the SEM directory. Note that our new SEM contact can
be used to study a sample of the cathode board that we received from Allflex.
Fernando has prepared the sample and given it to DSC. This will be done
when Brian returns.
Cathode Planning
- We have not gotten any updates on the shipment of our cathode board
order. We are expecting it any day now. Kim will check with Allflex
to find out when the package was or will be shipped.
- We have not yet devised methods for handling the boards when they
arrive from Allflex. This will have to be developed once the boards
arrive. Presently we are planning on doing a battery of QA checks on
all boards in the first order.
- Bill has not done any more work on the system to cut the cathode edges.
More to come when he gets back to this.
- Holes, holes, holes:
* We are still pondering deeply whether we will include the central
Kapton beam hole in the cathode boards and whether we will include
the side gas holes. Bill is convinced that the perimeter gas holes
in the frame are sufficient.
* Eugene's preliminary FCAL rate studies show only a modest improvement
if the Kapton in the central beam region is removed (of course in
all scenarios there is no Cu in the beam area). These calculations
are being followed up by Sasha.
* Bill and Mark want to do some test hole cuts (with a punch) in one of
our cathode prototypes. Bill has a small size punch and a large size
punch will be coming with the cathode order. Eugene and Micah will
measure the cathode tension for the prototype that they will use
before the cuts are made. This tension measurement will use the weight
deflection method already used by Eugene.
* The nominal plan as of now is to set the cathode tension on the
boards and then to add the central hole.
- Please consult regularly the cathode R&D plan to better understand the
order and the time assignments. Contact DSC with questions.
- Cathode flatness measuring system:
* All order parts n' pieces have arrived. The machined parts from FSU
have been shipped but not received. Bill will check into this.
* Mark has prepared the stabilizers for the granite table and has
attached the pieces for the rail installation.
* The granite table has been moved into EEL 126.
* As soon as the parts from FSU arrive, Bill and Mark will install
the rails and then turn things over to Micah who is standing by to
install/attach his parts n' pieces to the system.
* Micah stated that the scanning and display software will be ready
to go when the system is put together. He is mostly done with his
planned work.
- Eugene has posted GlueX-doc-1090 containing all details regarding his
studies on the cathode tension measurements and the allowed flatness
variations. He believes that if we can keep the flatness within 200
microns, we will be in good shape.
- Brian and Bill should begin to layout a detailed outline for the cathode
construction steps and circulate for feedback.
Wire Frame Construction
- The frame that was used for our wire tension load test (which is discussed in the FDC TDR) has been modified to include the pockets for the rigid-flex assembly and the bolt holes. It was machined to the nominal I.D. and O.D. of our wire frames. The foam core and the G10 skin were removed to an I.D. of 1032 mm to account for the problem with the HV decoupling capacitor placement. The plan is to redo our loading tests and measure the in-plane and out-of-plane distortions of the wire frame up to a load of 50 lbs max (the full wire load is about 35 lbs). Bill is working on the FEA calculations to determine the loading limits for the frame. This will also tell us how high in tension we can go with our load test, which uses a single wire down the middle of the frame (which is significantly worse that the distributed load of the real frame). - The nominal wire frame construction plan devised by Brian will be updated by Bill before the start of wire frame construction. The current version of the plan is posted on the FDC web page under the procedures link. It will be updated when Bill is done working his magic. - Bill will look into performing the PCB through hole enlargement next week. We need to make sure that the boards are handled properly and that the drilling out of the holes is properly done. The boards will then all need to be properly cleaned. - We are presently planning on borrowing an A-frame for EEL 126 for the wire frame construction (that Tim arranged). No other frames could be found in storage that we could claim. - PCB updates: * Kim has nearly finished the moving of the decoupling capacitors on the back side of the STBs. Fernando is now looking over the design drawings to make sure all is well. * A couple of changes have been decided upon by Fernando. One is that the protection resistors on the STBs that were chosen to be 10k will be changed to 1M. Fernando is working to decide if this change needs to be made on the boards for the full-scale prototype. Second is the HVTB resistors will be changed from an 805 package to a 1206 package to give an increased current rating. * The updated PCB drawings will be given over to Bill so that they can be put into the 3D model. * The PCBs for the FDC will need to be handled by all folks involved with more care. Many of the boards have sustained damage to the fragile lap ends. The damage is not severe enough to cause any construction worries, but handling procedures do need to be established and followed.
Test Frame Wire Winding
- IUCF has supplied the official report from the Phase 1 wire winding continuation and an official budget for Phase 2. Now that Elke is back, DSC will meet with her to go over things and we will discuss the situation (past, present, and future) in detail. The current idea is that we will have a teleconference with IUCF in the first part of next week.
Spacer Design
- Bill has not yet finalized a choice of material. It looks like the best choice may be polypropylene. He would prefer nylon-6 due to its superior mechanical properties, but nylon-6 absorbs water like a sponge. One problem with polypropylene is that it is very difficult to epoxy to it. If this ring has o-rings on both sides, there is no problem here, but Bill needs to be able to attach the gas inlet and outlet tubings. He described a number of potential work arounds. - We will be working to make a mechanical prototype as soon as the design is finalized.
Stack Assembly Procedures
- DSC, Brian, Tim, 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 use 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.
Gas System Design
- Slava is working 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. Slava provided some drawings that DSC will review. We will then 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.
Small-Scale Prototype
- Simon and Fernando are in the home stretch on completing the specification of the cathode and anode ASIC dynamic range. All required measurements have been completed and work is ongoing to finalize the test results in the document. What we have so far is posted as GlueX-doc-1070. - We still have the lingering issue of the problematic x-y plots from the 2-micron Cu cathodes. Simon will revisit this problem by taking some new pulser calibration data to see if this makes the apparent problem go away.
CAD Model
- We discussed a bit about making sure all relevant design features of the FDC are in the full CAD model. Tim will have Slava work to put in the capacitors and resistors on the wire frame PCBs into the model.
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.
