Minutes-11-6-2008
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FDC Weekly Meeting
Date: November 6, 2008
Participants: Daniel, Simon, Fernando, Mark I., Mark S., Herun, Roger, Drew
Next Meeting: November 13, 2008 @ 1:30 p.m.
Contents
Full-Scale Prototype Updates
- Procurements: * Roger has finished the design work on the cathode rigid-flex assemblies. He still has some minor work to do on the ground rigid-flex assemblies. He has been in contact with Allflex and is working out details on the specifics for the order. The plan is to order two runs of boards -- a first run of 5 to 12 prototypes, followed by a production run of about 70 boards. The first run is to ensure the boards fit in position given their tolerances. A quote has been received from Allflex of about $5k for everything. The PR for the first run should be ready for Elke to sign in about a week. Remember that before the design work is considered done, Fernando will double-checking the drawings. * Roger should communicate the board stuffing needs with Kim and she can arrange for the work in-house. * The order for the sense wire has arrived. Mark S. is making plans to test the wire according to our requirements (surface plating check in the SEM and strength test). Mark has been given a copy of the wire specification document prepared by DSC. The field wire order is expected any day now and it too will be tested. Brian will work with Mark to train him on how to handle the wire spools to prevent damage and contamination. * G10 ring order status: * Brian has verified that the order for the G10 rings has gone out the door. Expected delivery date is roughly 4 weeks. * 110IG Rohacell order status: * Bill checked that the Rohacell order has gone out. The expected delivery date is Dec. 17. - Mark S. will take responsibility for watching over the FDC component stores and keeping the database up to date. Kim will provide him with the excel spreadsheets for what we now have. All boxes are sitting in F117. - 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. - Kim has placed the procurement spreadsheet on the mdrive. * Location: M Drive/halld/Electronics, or for more sophisticated folks, /u/group/halld/Electronics. * Folks should fill it out in the given format.
Wire Frame Construction
- We have settled on a thickness tolerance for the wire frame of 8 mils to match the thickness tolerance for the cathode frames. DSC and Bill are working to complete a specification/tolerance document for the wire frames for circulation. - Additional prototyping work by Mark S. has led us to essentially finalize our PCB annulus lamination technique. A chamber-safe epoxy choice has been made (a type of JB weld adhesive) and studied to ensure that it is fully controllable under gluing pressure (no voids or epoxy on the board surface). Mark S. has constructed a simple notched scraper tool to control how much epoxy is in the lap joint. The prototypes that Mark S. brought looked beautiful. The machine shop is working on manufacturing a simple clamping jig designed by Bill. After some low-level design verification, this system will be used to glue up the PCB annuli for the full-scale prototype wire frames. This gluing should take place next week. - A new epoxy application system for laminating the G10/Rohacell layer to the PCB layer has been devised that gives a very satisfactory control of the epoxy during the vacuum-bagging procedure. A soft foam roller has been used that is dipped in an epoxy reservoir. The epoxy is then rolled on to the PCB boards. In the past, we used a hard-rubber fingerprint roller with epoxy poured onto the PCB. The new system has been shown to give fully satisfactory results to date. A few more tests are planned to study the seepage of epoxy through the holes in the circuit boards before declaring success. The prototypes that Mark S. brought looked beautiful. - The JLab machine shop is in the process of modifying one of our aluminum jig plates to work as a vacuum table. This will be done very shortly and will be tested out. - 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
- The specification/tolerance document for the cathode frames is being worked on. It will be circulated shortly. - Mark S. will check on the cathode boards in the storage box to make sure that there are no problems. This still has not been done yet. However, there has been regular checking on the nitrogen source. - Fernando has communicated with the W&M SEM folks and will be heading up another check of the surface deposits on our sample cathode board. More to come soon. - Bill has nearly completed the design of the cathode edge cutting system. He will need another week (when he gets back from vacation next week) to complete the fabrication drawings. We will then have a procurement window for some parts before we can test it out for tolerances. More soon. - Cathode flatness measuring system: * Micah is doing some test measurements now. He has defined a grid size of 1 in by 1 mm that allows a cathode scan to be completed in 15 minutes or so. * Micah will do a measurement of the surface flatness of our granite table and then complete the cathode flatness measurements with our high tension cathode prototype. He expects to have results early next week. * Waiting on results of measurements. Presumably some have been completed but no report is now available. - Brian has prepared a first draft of a cathode construction document. Bill is working on expanding it with available pictures. DSC passed his comments on to Bill to be added. - DSC and Bill have prepared a short-term cathode R&D schedule (derived from the full schedule that was prepared several months ago). It has been circulated to Elke, Brian, and Drew for feedback. We will need to have a meeting to figure out how much time we can get from Brian to work on this. The first work to be completed is to update the cathode tensioning system. This will lead to construction of a cathode prototype or two that will be used to finalize the cathode tension choice and the artwork distortions. Roger will have some redesign to do (most likely) to be sure that the board stretching does not lead to problems with the through holes. DSC stated that we will use one set of our new cathode boards to make a prototype. However, before this happens, we will work with blank Kapton sheets and our existing dummy boards to finalize all techniques and requirements. - We discussed a bit more about the glue strip design. Mark S. and Brian will study using 2-in Kapton tape with Hysol adhesive applied with the new soft rollers. There is hope that this may work and eliminate our worries about the glue strips. - Just before Bill left for vacation he had come up with a new idea for attaching the external grounds to the cathode boards. We will discuss this more fully with Fernando when Bill returns.
Full-Scale Prototype Wire Winding
- The IUCF folks modified the dates in the Phase 2 contract and this was O.K.'d by JLab. Looks like we are days away from a signed contract. - We are going to struggle from our end to get the wire frames to IUCF before the end of the year. 1 week to complete orders, 4-ish weeks for bits and pieces to arrive, 3 weeks to manufacture 4 frames, 2 days for shipping. (Heavy sigh). - The Moire pattern masks have been received by IUCF. They were inspected and found to be satisfactory. - IUCF sent us back our transport box for the wire frames. Brian has placed it in a secure (undisclosed) location.
Spacer Design
- Bill reported that we have a sheet of polyethylene and a sheet of polypropylene. The blue print 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.
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 will revisit this problem by taking some new pulser calibration data to see if this makes the apparent problem go away.
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.