Virginia Tech Update for Tracking Group, June 27, 2007

Juliette is gone for the next three weeks teaching talented high schoolers at Santa Cruz. But thankfully, she left Mark with code set up to do the collimator rotations described in the figure below. Mark will try to get that done next week.

Figure 1 - Roll, pitch and yaw for the 12 o'clock and 6 o'clock octants.

Drift Chamber: As reported in May, Norm and our spring/summer undergraduate research assistant Elizabeth Bonnell completed a full-size six plane (xuvxuv) chamber. The chamber underwent initial testing. Simple wire maps showed some missing wires and some "hotter than average" wires. The chamber was returned to the clean room for diagnosis. There was a variety of causes of the missing channels: * There was one cold solder joint on the end of a wire and two cold solder joints on a card edge connector. All the connections had previously been checked for continuity with an ohm-meter, but these were either missed or opened up since they were checked. Soldering will be done more carefully in the future. * Two dead channels were due to opens on a TDC ribbon cable connector. * Two dead channels were due to nicked traces on the circuit board that brings the signal from the sense wire to the edge connector. * All of the above problems were fixed. We had the aluminum end-plates Alodined (Chromate coating) with the thought that it might improve our ground connections (see Figures 2) on the Faraday cage. The chamber was reassembled and one leak was found at a circuit board/Ertalyte joint. This was fixed with epoxy. The chamber has been returned to the test room (see Figure 3) and is presently being flushed with gas for further testing. We still see some evidence of induced noise from the DAQ system (it appears to be our Struck 3100 VME controller). We would like to switch very soon to a system with the F1 TDCs and a VXI crate. Steve Wood says he has another VXI crate on order, so it can replace the one he will give us. All the stuff is available he just needs to collect it up when he gets time, so we hope to pick the stuff up in the next couple weeks. Work is still(!) in progress on adapting the HKS/SOS tracking code to do track reconstruction for our current 6-plane chamber. Mark hopes to be done with this in the next week. Figure 2 - The "golden" chamber with its fresh Alodine coating. Figure 3 - Chamber back in place in the testing area (on the Hokie orange table).

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