Minutes-2-25-2010
From GlueXWiki
FDC Weekly Meeting
Date: February 25, 2010
Participants: Daniel, Simon, Beni, Lubomir, Mark S., Bill, Roger, Fernando, Eugene, Brian, Casey
Next Meeting: March 4, 2010
Contents
Construction Space
- Glenn asked us to prepare a couple of room layouts for EEL 126. The first was for the additional 10-ft of space and the second for the space up to the wall. Lubomir made the figures and we reviewed them and the time lines. We will request that the additional 10-ft of space should be ours within 1 to 2 weeks and the rest by the first part of May. Lubomir has prepared a floor plan layout that we will send to Glenn shortly.
General Construction Updates
- The two-layer prototype continues under source tests in the cosmic ray test facility. We plan to open up the detector for work on and inspection of the HV busses by March 15 to give DSC time to work on the detector and also to diagnose the problem before circuit board procurement. - Casey and Mark have finished sealing the 24 through-holes in our third prototype layer with epoxy. For the bench test, we will place the wire frame on top of a spacer ring and the big plastic sheet (a sealing surface) and fill with the nominal gas pressure. We will then sniff for leaks around the upper cathode. This should happen next week. We will then make a plan for the next step. - We want to try putting the oxygen sensor in our system and measure the oxygen contamination on our input and output lines. Due to the worries about high input impedance of this device, we have some additional checking to do. We expect to attempt this work next week. - The preliminary FDC stack assembly document draft is located at: /u/group/halld/Engineering/PRELIMINARY DOCUMENTS. We will review this document in the coming weeks to update out-of-date or old procedures.
Frame Modification Studies
- The two laminates for the cathode boards (G10 skin + new inner G10 core) came back after fly-cutting in the machine shop. We have two dummy cathodes mounted to tensioning frames. The first cathode was tensioned to roughly 600 N/m and allowed to sit overnight. It will be glued to its frame today. We will tension the second cathode tomorrow and glue it to its frame on Monday. We will then prepare the ground plane and complete the sandwich lamination by the end of next week. - Bill has put together a few slides showing the frame design changes. - The redesigned frame piece for the wire board is expected back from the shop within a couple of weeks.
Wire Frame Update
- The wire frame construction document is located at: /u/group/halld/Engineering/PRELIMINARY DOCUMENTS. - Kim expects to be done with her work on the PCB redesign by tomorrow and will prepare the files for distribution to the FDC group early next week. We will also send the drawings to IUCF for Keith Solberg to check out. We want to start the procurement process for the circuit boards by the end of March. Hopefully none of the current/HV problems with the full-scale prototype are due to remaining design problems with the circuit boards.
Cathode Update
- The current draft of the cathode construction document is located at: /u/group/halld/Engineering/PRELIMINARY DOCUMENTS. - DSC and Fernando have inspected the cathode samples and have signed off on them. - The next rigid-flex design meeting will take place shortly. - We would like to push to get the cathode board procurement done by the end of March. - David Lawrence is working to give us input on the hole size in the cathode center. Stay tuned.
Prototype Testing
- The current version of the full-scale prototype test plan is on the GlueX portal as (GlueX-doc-1304). - To connect the full-scale prototype to the readout electronics, Fernando is designing a simple translator board that allows connection from the 24-channel preamp connector to the 16-channel connectors on the ADCs and TDCs. These boards will be ready shortly. - The signal cables for the full-scale prototype are being made up by Fernando's group and will be ready shortly. - The two-layer prototype has been under tests for several weeks. Beni has been measuring plateau curves and studying drift time spectra. His most recent studies are in the FDC Log Book. He has been comparing the chamber response to two different gas mixtures, 40/60 Ar/CO2 and 60/40 Ar/CO2. - The delivery of the remainder of the preamp cards for the full-scale prototype will be in mid-March or so according to Fernando. - Fernando will pursue purchasing enough cathode ground boards for all six cathode planes for the full-scale prototype. - A while ago we focussed on the wiggles seen in the reconstructed wire position from the cathodes (see log entry 419) in the FDC logbook. We believe that the periodicity seen is due to the algorithm Beni is using to determine the U and V centroids. Stay tuned.
Construction Updates
- No new updates on the wire inspection this week. - DSC has contacted Keith Solberg at IUCF regarding the status of the review of the Phase 3 budget for the wire winding. Keith indicated that this work is in progress and should be done shortly. - It is time for the next Phase 3 preparation meeting with Keith Solberg, Bill, and DSC. DSC will work to schedule this only after we have a preliminary Phase 3 budget in our hands. See the work plan at: Phase 3 Preparation Work - Master list on wire and cathode frame redesign work is located at: Frame Modification Work. - Bill continues working on a brief write-up of the summer IUCF work. When it is completed, we will circulate it for discussion with Tim and others. It will then be sent on to IUCF for budget estimates. - Lubomir presented some preliminary results of the study of secondary hits in the FDC as a function of wire length and position relative to the frame. More to come next time.
Mechanical Prototype
- DSC prepared a brief write-up regarding the FDC full-scale mechanical prototype. It was circulated around to a small group of folks. We will do a bit of work to beef this up and then post it for group comment.
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.