Moller Measurements for E02-006 PREX, March - June 2010

Last updated: Mar, 07 2011 moller@jlab.org
Here a summary is given of the Moller measurements done for E02-006 PREX running on March 11 - June 20, 2010.

The Moller results are presented in a table below and on the plot.ps or plot.png

For PREX new 'BRUTE FORCE' Moller target was built and installed. It uses a superconducting magnet for the Moller target magnetization saturation. Two alignments of the magnet magnetic field were done by alignment group (March 30 and April 16).
Three different Moller quads settings were used for PREX running period. Different combinations of the magnet alignment and quads settings require using different analyzing power value for the Moller data analyzes. The most of Moller measurement were done at 3T magnetic field. As it was shown later, the Moller target was not fully saturated at this magnetic field. Due to that, correction on the target saturation was done for 3T measurements.
As a result of combination of low beam energy, different quads setting and magnet misalignment, we had different Levchuk-effect ( ref1 and ref2 ) contribution for different magnetic fields.
Corrections of the Moller results on all of the effects were done.
More information about the corrections and systematic error is given here .
Beam polarization measurements with the Moller polarimeter were done at the beam current 1.5-3.0uA. Beam current for PREX data taken was about 50uA. Possible systematic error caused by the beam current difference was studied in the ref . Summary of the test with three different methods of the beam current adjustment is presented on the plot . From the plot a contribution to the systematic error due to the beam current difference for PREX running and Moller measurements is +/-0.3%. The total systematic error (including the beam current correction) is 1.12% 

  #    date      raw polar.  Cor. polar*  Stat.err.   Syst.err.  Wien filter 
                                   
  --------------------------------------------------------------------- 
  1  04.03.2010    -85.31       -84.85    +/- 0.10    +/- 1.12%   -59.0 
  2  04.05.2010    -88.71       -87.24    +/- 0.20    +/- 1.12%   -52.0
  3  04.17.2010    -88.53       -89.08    +/- 0.14    +/- 1.12%   -52.0
  4  04.22.2010    +90.58       +90.88    +/- 0.14    +/- 1.12%   -52.0   
  5  04.28.2010    -89.30       -89.60    +/- 0.12    +/- 1.12%   -52.0
  6  05.05.2010    -91.00       -90.39    +/- 0.15    +/- 1.12%   -52.0
  7  05.08.2010    +90.89       +90.29    +/- 0.15    +/- 1.12%   -52.0
  8  05.15.2010    -92.49       -89.94    +/- 0.16    +/- 1.12%   -52.0
  9  06.07.2010    -91.37       -90.49    +/- 0.11    +/- 1.12%   -52.0
* Levchuk-effect and target saturation corrections
03.30 - New Moller magnet alignment test.
03.31 - New Moller detector HV adjustment.
04.03 - The first Moller measurement with 'BRUTE FORCE' target. Target saturation test
04.05 - Spin dance
04.17 - New SC magnet alignment.
04.22 - Moller quads scan. Change Q1 setting
04.28 - EXPERT mode test (9uA of the beam current).
05.05 - New Q1 setting. EXPERT mode test.
05.08 - Moller quad Q1 scan. Target position test.
05.15-16 - Target saturation test
06.06 - The beam large charge asymmetry test.
06.07 - Repeat the beam large charge asymmetry test. Target saturation test.

The details of the measurements can be found here .