FDC Weekly Meeting
Date: January 14, 2010
Participants: Daniel, Simon, Beni, Eugene, Lubomir, Mark S., Bill, Casey, Kim, Fernando
Next Meeting: January 21, 2010
General Construction Updates
- With the prototype in the clean room fully reassembled, we repeated a complete series of leak checking. We also measured the input and output pressures in each layer. We came to the conclusion that our data did not make sense to us. It appeared that there was something different about the flow in the middle layer compared to the outer two layers. The pressure differential between the input and output seemed to indicate a larger leak rate, but this was just not bourne out by our leak check results. This lead us to take apart the stack again. - We did some baseline pressure measurements on a single protootype layer. We then reassembled the stack as two layers and have made a series of pressure measurements. Our last step was to reassemble the full-scale prototype back to three layers. This was just done and we will complete leak checking and pressure measurements tomorrow. Depending on what we find, we may repeat the measurements swapping the wire planes in layers 2 and 3 around. - We will be adding some stiffening pieces to the gusset arcs for the full-scale prototype to help reduce the flexing of the structure. We will work to move the detector to the test stand as soon as we can to begin readout studies. Stay tuned. - We wanted to get the full-scale prototype back into the test stand sooner, but we all felt that the studies we were doing to investigate flow and pressure readings in the individual layers were crucial to validate the design. - Mark has been tried to find some existing equipment to measure oxygen contamination in our exhaust gas. Nothing has been found. We do have an uncalibrated sensor in our gas system. We will look into whether or not this antique can be resurrected. - The preliminary FDC stack assembly document draft is located at: /u/group/halld/Engineering/PRELIMINARY DOCUMENTS. We will review this document after tests get underway on the full-scale prototype to update out-of-date or old procedures.
Frame Redesign Studies
- Beni has been in regular contact with Mihajlo Kornicer at IU regarding the studies of the modified FDC frame design. Mihajlo is having trouble getting his code working again and is getting help from several within the GlueX Collaboration. Folks are moving as swiftly as possible and we will continue to push to find out how we can modify the frames to ensure better gas sealing without adversely affecting the detector performance. - We are awaiting the inner frame pieces for the wire frame and cathode frames from the JLab machine shop. As soon as we have them, we will proceed to assemble frames with these pieces and test their mechanical properties. Stay tuned for details.
Wire Frame Update
- The wire frame construction document is located at: /u/group/halld/Engineering/PRELIMINARY DOCUMENTS. - The parts of the jig to use for the wire electroplating operation are in our hands. They will be assembled as we find time. - We need to prepare a document for the electrical QA of the preamp connectors on the wire boards. - Kim is following up with the contacts regarding large-area PCBs. She has talked to the board supplier and they can provide stock big enough for a single FDC wire frame PCB. The board house claims that they can make a single piece board. Kim is working to get the supplier and the board house talking so that the board house will be able to guarantee their product. Fernando is more worried about find an outfit to complete the Phase 1 board stuffing. Kim will be following up on this. We are trying to push with as much urgency as possible. - DSC, Kim, and Fernando will have some meetings over the next couple of weeks to go over the design work in more detail so that Kim can get started quickly when she can shift over to the board redesign. DSC will work to set up our first meeting early next week.
- The current draft of the cathode construction document is located at: /u/group/halld/Engineering/PRELIMINARY DOCUMENTS. - We need to prepare a document for QA/stuffing/cleaning for the cathode boards and a similar document for the cathode daughter boards and ground boards. Casey has a draft of a document that Mark S. began preparing. He will take this over and complete the document. - We have received word that the cathode material order should be in the U.S. now. Roger will check on this. It is at the U.S. distributor in Mn. They will inspect the order. If Allflex (only some 30 miles away) will agree to store the material until the start of the board work. - Fernando has come up with a plan to modify the design of the rigid-flex assemblies to increase the pitch. Bill has agreed with the plans. We will have a more detailed design meeting next month after Fernando's schedule clears up a bit. - Fernando suggested that the half-strips in the middle of the board be made with square ends as opposed to rounded ends. DSC will add this to Roger's work list. - We would like to push to get the cathode board procurement done on the time scale of this March. Stay tuned. - David Lawrence is working to give us input on the hole size in the cathode center. Stay tuned.
Cosmic Ray Test Stand
- The current version of the full-scale prototype test plan is on the GlueX portal as (GlueX-doc-1304). - 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. - To connect the full-scale prototype to the readout electronics, Fernando will design 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 should be ready in early February. - Beni believes that we have all of the HV and LV cables needed for the full-scale prototype tests. Fernando will take care of making up the necessary signal cables. - Mark S. will work with Beni to put together an adjustment system to position the source and trigger scintillator with simple horizontal and vertical adjustments.
- DSC contacted the W&M folks working on the SEM scans of our production wire samples. Waiting for a reply. - DSC is working to set up a meeting with the IUCF Associate Director overseeing the Wire Chamber Lab. We will try for a meeting at the end of next week. - Next IUCF meeting on Phase 3 preparations will take place in about 3 weeks. See the work plan at: Phase 3 Preparation Work - Master list on wire and cathode frame redesign work is located at: Frame Modification Work.
- 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.