Difference between revisions of "Minutes-1-27-2011"

From GlueXWiki
Jump to: navigation, search
Line 39: Line 39:
 
== Engineering ==
 
== Engineering ==
  
- Bill is working on some additional parts for the stringing system. The techs have been working with it last couple of weeks exercising different techniques. We discussed again the main issue so far, the flatness of the wire frame. Bill suggested using clamps that will be inserted between the G10 frame and the Rochacell ring. Fernando suggested a possible way to push the wire frame down from a supporting frame on the top. The way it works now is by taping the wires down to the board close to the soldering pads. This was proven to work: increase of the wire position deviations from ~10 microns to ~15 microns (sigma). Taping of all the wires is almost done and soon we will continue with gluing and soldering the wires.
+
- Bill is working on some additional parts for the stringing system. The techs have been working with it last couple of weeks exercising different techniques. We discussed again the main issue so far, the flatness of the wire frame. Bill suggested using clamps that will be inserted between the G10 frame and the Rochacell ring. Fernando suggested a possible way to push the wire frame down from a supporting frame on the top. The way it works now is by taping the wires down to the board close to the soldering pads. This was proven to work: increase of the wire position deviations from ~10 microns to ~15 microns (sigma). Taping of all the wires is almost done and soon we will continue with gluing and soldering the wires.  
  
 
- The testing of the "cheap" conductive epoxy was not very successful so far, it has high resistivity. Eugene: it might be better instead of spending time on improving the gluing technology, to use the "expensive" epoxy. Bill: the expensive epoxy has high viscosity and increases the thickness of the connections.     
 
- The testing of the "cheap" conductive epoxy was not very successful so far, it has high resistivity. Eugene: it might be better instead of spending time on improving the gluing technology, to use the "expensive" epoxy. Bill: the expensive epoxy has high viscosity and increases the thickness of the connections.     
Line 45: Line 45:
 
== Full-scale prototype tests ==
 
== Full-scale prototype tests ==
  
- Lubomir re-visited the unsolved problem that wires are not in the middle w.r.t. top and bottom cathodes. This time the long wires were scanned along their lengths. One sees (page 550) systematically that the wires are closer to the middle at the beginning of the wire going up at the middle of the chamber by up to 1.5mm. This may indicate that the cathodes are sagging. It could be due to pressure difference, gravitation, or electrostatic forces. The last two effects normally must be small. The holes on the cathode frames must eliminate the differential pressure on the cathode, but it could be that the ground plane sags and couples to the cathodes strongly in the middle. The plan is to investigate the pressure effects by changing the gas flow. The next step would be to turn the chamber upside down, but most likely at this position the chamber will not be operational. Therefore, before doing this any other ideas of what needs to be checked, are welcome.
+
- Lubomir showed a new plot (page 550) demonstrating how the ratio top/bottom strip signals changes over the plane of the top chamber. One possible explanation is deformation of the cathode/ground planes due to pressure difference in the different volumes. We discussed if it will be an advantage to have the volumes of all the chambers in a package connected together, i.e. to have holes in the ground planes that are now separating the chamber volumes. Now we are testing the bottom chamber.  
 
+
  
  
 
== Others ==
 
== Others ==
  
For the next collaboration meeting (Feb 2-3) Beni and Lubomir will decide about the FDC talks in the tracking session. Simon will talk about the tracking analyses in the off-line session.
+
NO MEETING next week due to the collaboration meeting (Feb 2-3) Beni, Lubomir and Simon will have talks on the collaboration meeting.
  
 
-->
 
-->

Revision as of 19:48, 27 January 2011

January 27, 2011 FDC meeting

Tentative Agenda

  1. Production (David)
    • Blue Crab status
    • FDC QA docs QA doc
  2. Electronics (Fernando, Chris, Roger)
    • Rigid-flex assemblies
    • Foil production status
    • Other
  3. Engineering (Bill, David)
    • Wire stringing
    • Other
  4. Full-scale prototype studies
  5. Other