Just as was done in the pp2006: longitudinal polarization, I calibrated using the technique described SpaceCharge and GridLeak Calibration How-To Guide. Just a couple notes:

• I did not even attempt to look at the no-calibration data as the pp2006: longitudinal polarization showed this to be of little help. I simply assumed that ZDC east+west would again be the best relevant scaler.
• Again, calibration was done without the beamline constraint with one exception. For the last pass, I used the values predicted by all the previous passes along with the beamline constraint. The result was a new data point which sits almost exactly on the fit curves, not changing the fits, which is good evidence that the fit had indeed converged.
• The fits for the offset parameter were not as good as the other fits, but almost certainly good enough to move forward.
• Spread in the measures of the SpaceCharge ionization did not improve in any significant way with the use of the beamline calibration. This implies that either the beamline calibration is not doing anything useful, or the spread in the sDCA distribution is dominated by something else.

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Here are the plots and output from my final iterative pass:

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Gene Van Buren