Minutes-10-8-2009

FDC Weekly Meeting

Date: October 8, 2009

Participants: Daniel, Beni, Bill, Simon, Fernando, Mark S., Mark I., Casey, Stephen, Roger

Next Meeting: October 22, 2009 @ 1:30 p.m.

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General Construction Updates

 - We are presently gearing up to begin stack construction for the
   full-scale prototype starting in the first part of next week. We will
   initially construction a single cathode-anode-cathode layer (using the
   two cathodes attached to our end gas windows) and work on measuring and
   eliminating gas leaks. The plan is to perform a 3D voltage check with in 
   an Ar-CO2 gas environment with the chamber at nominal plateau voltage to 
   be sure that there are no breakdown problems. Fernando will have a cathode 
   and an anode preamp board available for us to check some signals on the 
   scope. Stay tuned for details. We may have the opportunity to verify some 
   of the crucial design features of the detector in terms of signal to noise
   levels next week.
 - The preliminary FDC stack assembly document draft is located at:
   /u/group/halld/Engineering/PRELIMINARY DOCUMENTS. The document will be
   fleshed out during the assembly procedure for the full-scale prototype.
 - Tom Carstens has been working on moving the clean tent from the EEL
   building clean room to EEL 126. The move is nearly done. Due to the
   size of the clean tent, we are still finalizing the reorganization of
   EEL 126 and working to put a few things into storage until they are
   needed. The clean tent should be fully sealed by the end of this week.
   We will turn the air flow on shortly and make the tent clean in
   preparation for stack construction. Mark S. will find a particle counter
   to verify that the tent is sufficiently clean for construction. The
   fan speeds on the clean tent are adjustable and Mark S. will talk to
   Jack Segal for information on proper settings.

Wire Frame Update

 - Wire frame P1 status:
    * During handling on Friday of last week, 3 wires were broken on the 
      frame. They have been repaired and the frame is ready for final 
      electrical QA checkout and connector gluing. This work will take place
      today or tomorrow as P1 is the first frame needed for stack assembly.
      The frame will then ready for lamination to its cathode plane. This
      lamination will take place either tomorrow or Monday.
 - Wire frame P3 status:
    * This frame is ready for final electrical QA checkout and connector
      gluing before lamination to its cathode plane. All Snoop-related
      problems have been mitigated and DSC will pay off Fernando as soon
      as he can raise the cash.
 - Wire frame P4 status:
    * After sitting in an Ar/CO2 environment for 4 more days, frame P4
      is feeling much better. All busses are below 30 nA except for one
      which is at about 80 nA (but was improving with conditioning). This
      frame is essentially ready for final electrical QA checkout and
      connector gluing before lamination to its cathode plane. A couple
      of other minor operations are neede on P4, replacing two capacitors,
      filling in of a joint between the left HVTB and the filler board, and
      coating with the humidity sealant.
 - We need to have a dedicated meeting to design what the schedule for
   work on the Phase 3 wire winding will be. The highest priority for
   work scheduling will be doing work on upgrades of the wire winding
   facility. This includes a better strongback design, the design and
   construction of precision combs, modification to the wire winding
   table, and a list of other items with the system. Stay tuned, more
   to come.
 - The wire frame construction document is located at:
   /u/group/halld/Engineering/PRELIMINARY DOCUMENTS. We will include
   the information on the wire electroplating process shortly.
 - The parts of the jig to use for the wire electroplating operation
   are in our hands. They will be assembled as we find time.

Cathode Update

 - Progress updates:
     * Fernando is overseeing the QA electrical tests on the rigid-flex
       assemblies. We should be able to get another set or two delivered
       next week and all available boards by the week after next.
     * We do not have enough rigid-flex assemblies due to yield losses on
       the original order of 60 (54 are needed for the prototype). Roger
       will finalize the order today and we expect to have the remaining
       boards in our hands within 2 weeks. The order will be for ~25 boards.
     * Fernando has certified the soldering procedure of Mark S. and work
       has begun soldering the rigid-flex assemblies to the first cathode 
       frame for stack assembly. Four boards have been attached but still 
       need electrical QA. The work is taking longer than Mark S. expected 
       as the procedures are still being tweaked. Ultimately we expect to a 
       single cathode frame will need about 2 days for all flex assemblies 
       to be attached. The soldering work on the first cathode should be
       done tomorrow if all goes according to plan.
 - The current draft of the cathode construction document is located at:
   /u/group/halld/Engineering/PRELIMINARY DOCUMENTS.
 - Roger has been discussing packing of our cathode material for delivery
   to JLab.
 - 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.

Cosmic Ray Test Stand

 - Beni is continuing work to setup the cosmic ray telescope and test
   system in EEL 126. He has been working on getting the IU chambers into
   the readout. He has taken some data, adjusted the geometry alignment
   parameters, and is trying to make sense of the data correlating the
   IU chamber coordinates with those from the small-scale prototype. The 
   latest plots are in the FDC electronic logbook at:
   http://www.jlab.org/Hall-D/detector/fdclog/
 - We still have some mysterious behavior with the small-scale prototype
   response with wiggles in the X vs. Y distributions that need to be
   understood. Beni has gotten a larger data set on the small-scale
   prototype and the wiggles are still present. There seems to be a
   high-frequency wiggle and a low frequency wiggle. See the FDC logbook
   for plots.
 - Beni has started a bench test plan for the full-scale prototype and
   is presently working on it after incorporating feedback. The current
   information is contained on the FDC wiki page under the heading 
   "FDC test cosmic ray test stand".

Preamplifiers

 - Fernando reported that the issues with the ASICs seemingly having problems 
   with their linearity are not as bad a first thought. Optimizing the
   components mounted on the preamplifier boards was the cure and we will not
   have to wait for a new order! Fernando will have preamplifier boards for 
   our single layer voltage checks available next week.

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.