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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
 - 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   out-of-date or old procedures.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.

Cathode Update

 - 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.

Construction Updates

 - 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.

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.