The beam is polarized. A sharp change in X position (hence energy) was observed at 3C12 during one of the IHWP out runs.
Charge Asymmetry 6.48715 Global Laser Phase 0 Half Wave Plate 1 Hall A Photocurrent 0 Hall A Slit pos 8 Hall A atten 120 Hall A current 0.0272639 Hall B Photocurrent 4.64436 Hall B Slit pos 16.7 Hall B atten 236 Hall B current 30.4015 Hall C Laser att. 407 Hall C Photocurrent 49.3819 Hall C Slit pos -0.996094 Hall C current 37.8523 Helicity Mode 0 Int. Las. Phase Noise 1.37 Laser Phase measured -4.51224 Negative PITA Voltage 2.9304 Positive PITA Voltage 3.2381 Pre-Buncher 1 Rotatable hwp 6070 Wien Angle 2.49577 X spot position 1280 Y spot position 1120