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    User name Yi Qiang

    Log entry time 11:57:57 on November 13, 2008

    Entry number 248543

    keyword=EPR Calibration

    I did 2 sets of EPR Calibration of transverse polarization with slightly different settings. Both measurements gave very consistent calibration constants (1.473 vs. 1.475 %/mV), and the number is also very close to the not-so-successful EPR calibration we performed last on Tuesday. (1.47 vs. 1.45 %/mV).

    The offset issued was determined to be the input saturation of the PI box. Increasing the lock-in sensitivity from 500uV to 1mV solved the problem.

    The new calibration constant is quoted from the second measurement which has a higher precision (relative error ~ 1 %).

    The polarization after 2 EPR measurments is about 60%

    A copy of this log entry has been emailed to: jpchen@jlab.org, chiran@jlab.org, jinhuang@jlab.org, jkatich@jlab.org, zhangyi@jlab.org

    EPR Sweep #1

    EPR AFP #1

    EPR Calibration #1

    EPR Sweep #2

    EPR AFP #2

    EPR Calibration #2