FDC Weekly Meeting
Date: June 26, 2008
Participants: Daniel, Simon, Kim, Roger, Mark, Micah, Eugene
Next Meeting: July 3, 2008 @ 1:30 p.m.
- Roger has basically completed the cathode design drawings. He has sent the design drawings to Fernando for blessing on the layout. Fernando is currently on vacation, but he may be able to bless the layout remotely. After the meeting DSC spoke with Bill Crahen who has looked over the gas hole and through-hole locations and given his final blessing on these. We still need to include the cathode layout into the CAD model and this will be done at some point in the near future (probably after the CD-3 deadlines). - The plan is to procure the cathode boards for the full-scale prototype in a two-stage process. We will first procure two full sets of 2 micron Cu boards and two full sets of 5 micron Cu boards. We received a quote this week from Allflex on the first order. It has come in at $3.2k per set with a $2k tooling charge. After we bless these boards, we will hopefully then move to order an additional 4 sets of each board type. - Roger has all other information necessary to complete the PR and hopefully this will converge very shortly so the order can go out. - DSC asked Roger to meet with Fernando upon his return next week to lay out the plans for electrical checks on the delivered cathodes. After we finalize the plan, we will order the test equipment needed if we do not already have it. - Roger is working with the Allflex representative to find whatever information is available from Nippon on the raw material specifications. - Additional solder tests of the rigid-flex assembly to the cathode board mock up will proceed after Roger gets the hot air pencil from Fernando. This work will wait until the cathode board PR is completed and Roger has time in his schedule. - Due to the height of the solder connection between the cathode board and the rigid flex assembly, we will have to revisit the design from the standpoint of adding clearance pockets on the surfaces that mate up against this solder region. Chuck is responsible for looking into this and letting us know. - Brian will modify his Lucite box design for storage of the completed cathode planes. The cathode planes can stack upon one another (unlike the strung wire frames). He will make some minor modifications to the existing box drawings and prepare the PR. This work will proceed in July when Brian gets back to town. - Bill found a precision straight edge 1.5 m long for $750. We can decide in the upcoming weeks if this is appropriate to purchase to cut our cathode boards to width.
- The order for the 5 ft x 5 ft granite table has now gone out. The table should arrive in about 2 weeks of time. - The work to modify the existing aluminum tooling plate and make a second are in the queue in the JLab machine shop. Simon found out from Casey that due to a new high priority FEL job, our work is not scheduled to begin until August. DSC has contacted Elke to find out how we can get our priority for this work increased. - Brian found that the power cord for the clean tent did not reach any of the recepticles in the clean room. He made a request to plant services to have an outlet installed. No update on this work. - Brian and Bill will work to update our wire frame construction sequence document. Brian will provide a first draft to Bill who will work to polish it up. We would like to provide this to Casey so his group (and of course ours) can full understand the procedures. This work has not yet gotten underway.
- No work done on cathode prototyping this week. Still need to pursue techniques to tension cathodes to a particular (pre-determined) point. We still need to pursue mechanical solutions (fixed weights to define the tension). More work when Brian returns from vacation. - We will try to develop a cathode tension measuring system using our laser measurement head. The procedure will be to direct a puff of air at the center of the cathode and measure the amplitude fluctuation vs. time through the laser measurement system. Fitting this amplitude distribution will give us (hopefully) the fundamental frequency that we should be able to convert into the membrane tension. More to come.
Test Frame Wire Winding
- We had a teleconference with IUCF at noon today to finalize the planning on the continuation of phase 1. A budget of $10k was agreed on by all parties and we will move ahead with finalizing the paperwork early next week. We then will want to ship two additional wire frames to IUCF for this work. In this regard, DSC will provide a brief statement of work for Elke to review this week and we will then send it on to the JLab contracts folks. - We have one frame ready to go to IUCF for the continuation of Phase 1. A second wire frame is being worked on in the JLab shop to add the through-holes to the frame. As mentioned above, our delivery date has slipped considerably in the JLab queue due to other work. DSC has contacted Elke to get the work on the second frame done ASAP. More information to come. - DSC is working with Steve Christo to prepare a wire specification document for the tungsten and CuBe wires leading up to procurement. Steve is preparing a document for the Hall B chambers and we will most likely adopt this document for Hall D. DSC reviewed the existing Hall B documents to give folks a flavor of how these documents have been prepared in the past. We need to make decisions on what is required for the FDCs.
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.
Cathode Flatness Measurements
- Micah is working on upgrading the system readout electronics. He has prepared a time line for the system work so that we can have a rough idea how he plans to make progress and complete the system upgrade and complete the required suite of measurements before the end of the summer when he disappears. DSC will go over the schedule and give feedback. - Micah will also put together a list of things that need to be purchased so that we can start the procurement process as soon as we can. This is nearly ready. When the plan is fleshed out, DSC will meet with David and Micah to go over things. - Micah presented some laser scans done on a frame that Denny had already done some measurements on. In short, the features seen in Denny's measurements were not reproduced in Micah's data. This needs to be investigated and we suggested a number of simple checks that could be done as basic sanity checks that the system is providing accurate data. It was also the case that Micah's data showed a bulge that was twice as big as what Denny found.
Cooling System Tests
- Fernando is nearly ready to perform the cooling system measurements. Bill has ordered a flow control valve that will arrive shortly and be installed in the system.
Gas System Design
- Vladislav (Slava) Razmyslovich is working on a preliminary layout of the gas handling system for the CDC and FDC in preparation for the upcoming systems review. We will sit down with him in a specialized meeting to review the design concepts when we get a chance.
- Kim needs to provide an instructional writeup for the Phase 1 and Phase 2 wire frame PCB component attachment. This is on her to-do list, but is not a high priority for now.
Cathode Board Discussion
- 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.
- Simon has continued his data acquisition with the small-scale prototype and has taken new 55-Fe source data and cosmic data with the new grounding configuration. He in principle has everything that he needs to complete a first attempt at extracting numbers for the cathode and anode dynamic ranges. However, there are a number of assumptions that we will have to make along the way. Certainly these assumptions will have to be advertised and discussed. Simon will aim to make a presentation to the Hall D group next Wednesday as well as to update his GlueX note on this topic. This work is posted as GlueX-doc-1070.
- DSC has collected all of the available FDC subsystem design drawings and placed them on the FDC website. The URL is: http://www.jlab.org/Hall-D/detector/fdc/drawings.html. Folks should go through the drawings and let DSC know what drawings and/or categories are missing for a complete design set. - Also folks should send DSC the latest design drawings where there have been changes to keep this web site up-to-date through the review season.
- The FDC short-term work list has been posted on the FDC web site (see http://www.jlab.org/Hall-D/detector/fdc/). 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.