OPTICAL DETECTION OF ELECTRON POLARIZATION

A method is suggested for measuring the polarization of low-energy electron beams by observing the polarization of the light emitted by mercury atoms following their excitation by electron impact. It is shown that the asymmetry of the left and right circularly polarized components of the 2537 Angstrom radiation of the even isotopes is approximately equal to the longitudinal polarization of the incident electron beam. The efficiency of such a detector is estimated for incident electron energies near the excitation threshold and its expected performance compares favourably with that of a typical Mott detector. Some distinctive advantages of the proposed scheme are pointed out.