OPTICAL ELECTRON POLARIMETRY WITH HEAVY NOBLE-GASES

We have measured the polarization of fluorescence emitted by the noble gases He, Ne, Ar, Kr, and Xe following impact excitation by polarized electrons. In He, the 3(3)P --> 2(3)S transition was studied; in the heavy noble gases the np(5)(n + 1)p D-3(3) --> np(5)(n + 1)s P-3(2) tr ansitions were analyzed. We investigated these transitions as candidat es for efficient optical electron polarimetry and found that, because of their larger excitation cross sections and analyzing power,the heav y noble gases are superior to He, which had been used previously as a polarimetric target. Several issues with regard to the implementation and accuracy of optical electron polarimetric techniques are discussed .