User name Moffit
Log entry time 10:47:08 on January 9,2003
Entry number 91202
keyword=Half-Wave Plate ScanAt 0400, G0 began their scan of the Rotatable Half-wave Plate.... a common element on the injector laser table that effects the Charge Asymmetry observed in every Hall.
This scan ended at 1000 (G0 DAQ and Beam problems made this scan a bit more time consuming than was expected).
Quick result: G0 has set the half-wave plate the 37.5 degress (Close to where they expect to minimize the charge asymmetry for Hall-C).
**** At this angle, Hall-A measures a charge asymmetry of ~-2400ppm ****
Below are the details of the scan that was performed by the Parity DAQ:
Run----RWP Setpoint----Angle----Qasy(ppm)---G0-Qasy
1156 0 0 239 146
1157 750 15 -1000 294
1158 1500 30 -1300 294
1161 2250 45 -1423 -428
1162 3000 60 -2622 -794
1163 3750 75 -4817 -1135
1164 4500 90 -6148 -1162
1168 5250 105 -5265 -1571
1169 6000 120 -1970 -684
1170 6750 135 3057 519
1171 7500 150 6916 1372
1172 8250 165 6020 1565
1173 9000 180 2366 1135
1174 1875 37.5 -2442 -733
Attached is plot of the scan observed in Hall C(figure 1) and in Hall A(figure 2)
FIGURE 1
FIGURE 2
