Region III Wire Chamber Report, Mike Finn, September 12, 2007.

• All G10 boards needed for the Region III assembly were delivered last week. John has dried assembled a complete set of boards of each type.  All components fit together nicely, and all holes line up. Spot checks of critical dimensions agree with specs.  Below are a couple of pictures of  G10 boards on the gluing jig with the dowel pins in place. A single layer to be glued is shown in the first picture. The glued board and backplane are then moved to the wiring jig for final assembly. A five layer stack, containing one layer of each type, is shown in the second picture. There will be eight layers of boards per chamber.
  
  
• Several students now know how to string wires, and all will eventually be trained. After a day of experience, students are able to string wires without breaking them. There is no sign of creeping in the wires that have been strung for over a month.
• Here is an average position histogram for 18 wires made by Brian. Wire-to-wire positions have a total spread of 350 microns, more than I would like, although insignificant from the point of view of the experiment. What we want to do is get the outliers to fall within a tighter envelope (half the wires are within 50 microns of each other). The placement jitter should go down as we get better with our technique. No problems have been encountered with the gluing technique thus far. A larger number of wires have been strung in our test set up covering different regions of the chamber. We plan to measure these to see if there are any systematic effects along the length of the chamber or at boundaries of the alignment segments. All testing has been done with 20 micron wire so far. We will begin testing the 25 micron wire we actually plan to use shortly.
   
• Brian and Josh are working on an automated scheme for the wire tension readout. Here is a typical tension scan made by Siyuan. We are only interested in knowing whether the wire tension is constant to about 2%, so a relative quick testing procedure is envisioned. Any wires failing the tension test will be removed and replaced.
  
• Final assembly of the chambers are awaiting production of the wire chamber readout interface boards.  Klaus has a design for the boards that he wants us to run by the JLab staff before sending out the order.
• The aluminized Mylar ground plane stretching frame is being redesigned to get the cost down. David and I think that the design can be significantly simplified.
• Most of the shipment of aluminized Mylar has arrived:
  • 165 feet of the 200 ft ordered of the single-sided material (the remaining 35 feet are on backorder).
  • all 300 feet of the double-sided material.
• We have five graduate students currently assisting on this construction project, three of which have just passed their PhD qualifiers and are interested in doing thesis work with the Qweak project.  An ad is out advertizing for a replacement for Klaus. We can hire undergraduates as needed, so we are not manpower limited.