The figures plot Compton asymmetries/beam polarization as a function of run number. This is a decent proxy for time, since each run lasted approximately two hours. Run 16085 (the first run) was shorter, which is why its error bar is larger.
All error bars are statistical only. I have not accounted for any systematic errors within the Compton.
Fig. 1 shows the maximum Compton asymmetry computed separately for the left-polarized laser state and the right-polarized laser state. These are approximately symmetric about zero, as they should be.
Fig. 2 shows the magnitude of the Compton asymmetry, averaged over left and right polarization states.
Fig. 3 shows an extremely rough polarization estimate resulting from
these asymmetries. We are not yet equipped to report absolute
polarizations with the Compton (we need a better detector response
function for this). In order to arrive at this polarization estimate, I
used a cross-calibration to the Moller measurements taken Feb. 11 and
Feb. 19 (in the linked post). However, this is an imperfect calibration:
the Compton measurements could not be taken simultaneously with the
Moller measurements and the absolute beam polarization may have shifted
between the two measurements.
A copy of this log entry has been emailed to: brads, vasulk, camsonne