FDC Weekly Meeting
Date: October 9, 2008
Participants: Daniel, Simon, Brian, Mark I., Eugene, Bill, Micah, Herun, Elke, Kim, Tim, Fernando
Next Meeting: October 16, 2008 @ 1:30 p.m.
Full-Scale Prototype Updates
- Design Decision: * We will be switching from 31HF to 110HF foam in all composite FDC frames. - Procurements: * Roger has not finished the design work for the cathode rigid-flex assemblies. We should aim to complete this work by the end of Oct. * Elke asked us to prepare a spreadsheet listing all expenditures for the full-scale prototype. Kim has prepared a draft of this, but she still needs input from Brian, Roger, Lorelei, Simon, and anyone else who has ordered parts n' pieces. * Brian has completed the PRs for the sense and field wires for the full-scale prototype. Both have been signed by Elke. DSC prepared two documents for our wires: Wire Specifications Document and Wire Testing Document. These documents have been passed on to the wire suppliers. Brian indicated that Little Falls had no problems with the CuBe wire spec. However, CFW did not like our heat treatment requirement. Brian will check with Steve Christo to get some feedback on this requirement. * Brian will be responsible for preparing the order for the G10 rings for the full-scale prototype. We should be able to put this order together rather soon. Brian is in contact with the company regarding the thickness specification. * Bill will be responsible for preparing the order for the 110 Rohacell foam for all FDC frames. Note that whether we order 110IG (Industrial Grade) vs. 110HF (High Frequency) does not matter. The choice should be on availability and cost. - Working Space: * We need to make sure our clean room work is done is the clean room and our non-clean work is done in EEL 126. Let's try to utilize our space properly. * A new shelving unit has been installed into EEL 126 that makes the space usage much more tidy and efficient. This looks good. All table tops in our space are now amazing exposed! - Storage: Kim has been amassing various and sundry FDC-related components in her area. She will bring them over to Simon for storage in F117 when she gets a chance. We are trying to find someone to create and maintain a database for the FDC components that have been ordered and are awaiting use. - 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
- We have settled on a thickness tolerance for the wire frame of 8 mils to match the thickness tolerance for the cathode frames. Elke wants us to write this up. - Bill and Mark have prepared a laminate with 110HF with some reasonable success. Bill has indicated that the flatness of the 110HF sheets varies from sheet to sheet, but that we should be able to select sheets flat to 5 mils or better. It seems that we should order the foam sheets with allowance for waste and pick out the best sheets for our use. We should be able to meet the flatness requirement. Bill is now in contact with the Rohacell folks as they are working to see what flatness tolerances that can deliver. - For the next Rohacell order for the wire frame, we will add allowance for the two epoxy layers and make the Rohacell a few mils thinner. - Note: A new design study has indicated that we do not need solid (one piece) Rohacell cores. We can split these up into quarters. This eliminates significant material waste and does not compromise the ring strength (so sayeth all engineers present at the meeting). - We decided to use the solder sample boards to finalize the PCB lamination procedures. We will then laminate the PCB ring to one of our existing G10/foam laminates. Photographs will be taken of each of the steps. - Fernando will look at the PCBs that came back from Greg Arnold's group to verify quality. He will also have Herun redo the electrical QA on the boards before construction. - Bill will look over the aluminum jig plates to check the latest work by the machine shop to add the clearance holes. - The wooden shipping box will be shipped back to JLab by IUCF. It looks like the paperwork has been completed. - PCB updates: * Kim has 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. * 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.
- Elke wants us to prepare a write-up for the cathode frame tolerance. - Mark got the nitrogen flowing through our cathode box using the dewar that Brian ordered. Brian will check on the boards to be sure the environment inside the storage box is O.K.. - The W&M SEM group did some study of a small piece of our sample cathode board from Allflex. This sample was one that was stained with some sort of surface contamination. Their mass spectrometer analysis revealed only copper. This is at odds with what Fernando found, which is that this contamination appears to be non-conducting. Fernando has done some additional resistance measurements and the material has resistances of 10k to 100M. This could be copper oxide. We want to close the loop on what the heck these are splotches are. Fernando will go and talk with the SEM folks to see if they can figure this out with us. - Roger will contact Allflex within the next week to follow up with the sales representative on when we plan to place the order for the remaining boards for the full-scale prototype. - Bill has not done any more work on the system to cut the cathode edges. More to come when he gets back to this. - Central cathode board hole: * We discussed more about the central hole in the cathodes. This is not required for gas flow or pressure equalization. Alex Somov has completed some new MC studies showing that the effect of the Kapton on the FCAL rates are at the 10% level. So, apparently we do not need to include these holes. - Cathode flatness measuring system: * Micah is working to get the system operational. He is very close. He will begin by measuring the surface flatness profile of the granite table. - Brian and Bill should begin to layout a detailed outline for the cathode construction steps and circulate for feedback. - DSC wants more parallel development. Mark will focus mainly on the wire frame R&D and Brian will focus more on the cathode R&D. However, in the short term, the wire frame development has top priority.
Full-Scale Prototype Wire Winding
- The Phase 2 winding paperwork has now been signed by the 12 GeV folks and passed on to our contracts people. The contract should be in place very shortly. - DSC has gotten final specifications on the Moire masks from IUCF and passed this onto Roger. He has asked Roger to have this work completed in about 1 month. - It may be, given our current estimates of schedules, that we will not be ready to send the frames to IUCF before the end of November. This schedule should come into crisper focus in a few weeks. It all depends on when we can place the Rohacell and G10 orders and what the turn around time is. We need 3 weeks to make the frames one all parts are in.
- We are presently focusing on two different choices for the material of the solid spacer. One is polypropylene, and the other is Noryl. Noryl is more expensive, but may have less handling and construction costs. We need to do a price estimate. We can easily laminate Noryl to the cathode board and eliminate one o-ring. Polypropylene does not epoxy well and would need to undergo an acid etching step to better prepare the surface to receive the epoxy. Bill will look into this more. - We will be working to make a mechanical prototype as soon as the design is finalized.
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 is doing some ANSYS model (with his new-found skills) to better study the connector that goes from the daughter board card to the cooling loop. He will add these studies 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.
- 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.
- Simon and Fernando have completed their studies of the dynamic range for the anode and cathode ASIC dynamic range. The study results are posted as GlueX-doc-1070. Simon and Fernando are now working with the CDC folks to help them finish their studies. No word yet on when they will be done and ready for sending things off to Mitch. Stay tuned. - 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.
- 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.