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    User name kelleher

    Log entry time 23:36:30 on March 23, 2006

    Entry number 168016

    keyword=New NMR calibration number (and NMR signal)

    This evening, Gordon and I performed an EPR calibration on Edna. This is our first calibration with this new cell, but our number is consistant with the calibrations performed on the other cells when various systematic effects are taken into account. Because of this consistency, we feel confident that the measured calibration number is reasonably accurate.

    This is an online number that we hope to improve though our ongoing studies. Within the next few days we would like to change the helicity of the He-3 with respect to the field, as this will help us evaluate our systematics. It is possible that these tests will nudge the central value of the calibration upwards by a few percent (relative). For now, to be conservative, we will stick to our measured number. As with our previous calibration numbers this should be considered in the good to 10% spirit.

    The calibration constant that we have agreed upon is 0.431%/mV

    As part of this calibration exercise, we performed a number of NMR measurements. The result of the final NMR measurement gives the following results:

    UP: 121.6 mV DOWN: 120.7 mV

    This corresponds to the following polarization:

    UP: 52.4 % DOWN: 52.0 %

    So, our current average polarization is 52.2%

    A copy of this log entry has been emailed to: bogdanw@jlab.org, tdaver@wm.edu, jpchen@jlab.org, kolarkar@jlab.org