The Compton polarimeter at the SLC

Compton scattering provides a fast and accurate measurement of the longitudinal polarization of electron beams available at linear colliders. At the SLC, green (532 nm) circularly polarized light from an Nd:YAG laser, frequency doubled, collides nearly head-on with electrons after they have passed the e/sup +/e/sup -/ interaction point but before they have encountered any dipole bending magnets. Unique to this application, the recoil electrons, rather than scattered photons, are detected, after being momentum analyzed by the bending magnets nearest to the interaction point. Thus we achieve spatial separation of several centimeters between electrons from scattering at different Compton angles. >