The attached plots show the quality of the VDC time-to-distance conversion (averaged over all track angles) before and after the VDC electronics & HV changes. The first plot is from the 650 kHz December 2009 test run, the second, from Saturday's detector calibration run 1200. In both cases, "distance from time" was calculated with the exact same conversion function and fit parameters that have been used for 10+ years. The effect of the HV change is evident (lower slope, mismatch at small distances, etc.), although not dramatic. The yellow line represents the ideal dependence.