The commissioning of the LEP polarimeter

A laser polarimeter has been installed in LEP to measure the transverse beam polarization. The authors describe the layout, the production and the control of the polarization of the laser light, the photon detector, and the data acquisition philosophy. The commissioning experience in the first year of operation of the device is discussed together with recent results on the detection of transverse polarization. The behavior of the instrument was found to be in agreement with the predicted performance. The control and the optimization of the polarization states of the laser light were performed from the optical laboratory, and the quality of the circular light was adequate to produce observable effects on the mean-shift of the vertical distributions.<
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