Moller Measurements, Jul-Nov 1999

Moller Measurements in Jul-Nov 1999

Last updated: Mon, 29 Nov 1999 moller@jlab.org

Here a summary is given of the Moller measurements done for the period of July - November 1999. In July, HAPPEX was running (the results are also described in here), while later E84-012 and E89-19 were running practically in parallel.

The longitudinal beam polarization is calculated as:
P=A/P_targ/cos(a)/Azz,
where

A is the asymmetry observed
P_targ is the target polarization. We used a constant value of P_targ=7.6% for all the data
a is the target angle with respect to the beam. This value was observed on a dial attached to the target mechanism and also was calculated using the measured counting rates at the given target position and at 90^o. In order to reduce the systematic error we always took an average of two measurements: one at about 20^o and another at about 160^o.
Azz is the analyzing power

The laser phase had been checked before the measurements.

The table of all the measurements is shown here:


  #   m   d   h   1-st run   GeV     Polarization   COS(spin)    uA Laser:power atten slit    loss  1/2wave B   C
  1   7  10  10    7006    3.3250   75.63 +/- 0.18   -0.997    0.503      73.0  500. 15.90    0.66   0      0   0
  2   7  12  17    7023    3.3250  -74.35 +/- 0.17   -0.997    0.545      73.0  500. 15.80    0.81   1      1   0
  3   7  12  18    7053    3.3250  -74.88 +/- 0.20   -0.997    0.137      73.0  500. 13.90    0.44   1      1   0
  4   7  13  13    7066    3.3250  -76.02 +/- 0.18    1.000    0.509       0.0    0.  0.00    0.00   0      1   1
  5   7  15  14    7127    3.3250   76.27 +/- 0.19   -1.000    0.478      73.0  500. 15.50    0.99   0      0   0
  6   7  15  20    7147    3.3250   76.56 +/- 0.18   -1.000    0.547      73.0  500. 16.00    0.64   0      0   0
  7   7  15  21    7177    3.3250   76.37 +/- 0.18   -1.000    0.231      73.0  500. 14.50    0.53   0      1   0
  8   7  22   8    7190    3.3250  -71.37 +/- 0.17   -0.997    0.575      73.0  500. 15.75    0.91   1      1   1
  9   8   4   0    7318    1.1480   79.72 +/- 0.26    0.983    0.189      73.0  500. 14.58    0.45   0      1   1
 10   8  12  12    7393    0.8570   78.53 +/- 0.21   -0.997    0.206      73.0  200. 16.50    0.49   0      0   1
 11   8  14  17    7424    1.6690   77.57 +/- 0.19   -0.920    0.275      73.0  355. 15.50    0.78   0      1   1
 12   8  18  12    7452    1.6690   77.54 +/- 0.19   -0.920    0.253      73.0  328. 16.15    0.38   0      1   1
 13   8  19  21    7477    4.1080  -80.73 +/- 0.14    0.996    0.525      73.0  500. 15.70    0.88   0      1   1
 14   8  24   7    7608    4.1080  -80.17 +/- 0.15    0.995    0.303      73.0  600. 15.45    0.66   0      1   1
 15   8  24  18    7639    1.6690   74.85 +/- 0.16   -0.921    0.301      73.0  500. 15.30    0.73   0      1   1
 16   8  26  16    7664    1.6690   75.87 +/- 0.17   -0.919    0.271      73.0  500. 15.00    0.72   0      0   1
 17   8  27  19    7690    1.6690   75.73 +/- 0.16   -0.920    0.290      73.0  500. 15.01    0.77   0      1   1
 18   8  30  10    7718    1.6690   76.11 +/- 0.16   -0.920    0.291      73.0  500. 15.30    0.71   0      1   0
 19   8  31  15    7743    1.6690   75.94 +/- 0.17   -0.920    0.255      73.0  500. 15.20    0.65   0      1   1
 20   9  21   9    7778    1.2680   65.08 +/- 0.20   -0.976    0.220      75.0  200. 17.10    0.37   0      1   1
 21   9  24  10    7807    2.5020   64.62 +/- 0.18   -0.988    0.308      75.0  600. 16.20    0.29   0      1   0
 22   9  27  11    7834    2.5020   62.90 +/- 0.15   -0.988    0.453      76.0  600. 16.20    0.43   0      1   1
 23  10   2  12    7863    2.5010   61.07 +/- 0.20   -0.988    0.401      76.0  600. 15.46    0.87   0      1   1
 24  10   5  16    7915    2.5010   58.75 +/- 0.21   -0.988    0.362      76.0  600. 15.00    0.96   0      0   1
 25  10   8  13    7947    2.5010   66.55 +/- 0.20   -0.988    0.284      76.0  600. 15.00    0.75   0      1   1
 26  10  15  17    7995    2.4980   68.36 +/- 0.22   -0.988    0.324      76.0  600. 16.20    0.30   0      1   0
 27  10  20  15    8016    3.1150  -68.71 +/- 0.23    0.995    0.305      76.0  430. 16.70    0.20   0      1   0
 28  10  23   9    8049    3.1150  -67.70 +/- 0.22    1.000    0.293      76.0  600. 17.40    0.14   0      1   1
 29  10  29  14    8090    1.9470  -70.36 +/- 0.17    1.000    0.249      75.0  600. 15.30    0.61   0      1   0
 30  11   2  13    8118    1.9470  -73.28 +/- 0.17    1.000    0.296      75.0  600. 14.80    0.75   0      0   0
 31  11   5  18    8138    4.7920  -70.00 +/- 0.18    0.997    0.305      75.0  600. 15.15    0.80   0      1   0
 32  11   6  15    8167    1.0000  -73.98 +/- 0.17    0.994    0.197      75.0  600. 14.80    0.50   0      1   0

where the date is given in the columns 2-4, the average polarization for 2 target angles is presented in the columns called "Polarization". The 1-st Moller run of the measurement is shown in column 4. The column named "COS(spin)" shows the value of cosine of the expected spin angle in the hall. The column named "loss" shows the estimated value of the "additional" attenuation parameter (see the details here). The columns named "B" and "C" show whether the lasers of Halls B and C were on or off during the measurements.

The Moller results, along with the Mott polarimeter results and indications of the injector and other changes are presented on a plot. The PAW macro which creates this plot is available from E.Chudakov.

The line "radiation damage" indicate the moment when the Moller detector was slightly damaged by radiation during the tune-up of the beam. Mostly, the left top lead glass counter was damaged, loosing about 40% of the amplitude. In several days the detector has practically recovered.