Impact Ionization of Polarized Atoms by Polarized Electrons - Measurement of the Integral Polarization Asymmetry

Raith W, Baum G, Granitza B, Leuer B, Steidl H. Impact Ionization of Polarized Atoms by Polarized Electrons - Measurement of the Integral Polarization Asymmetry. Institute of Physics Conference Series. 1992;(122):247-253.As a continuation of our asymmetry measurements for metastable helium (Baum et al. 1989) we are now concentrating on high-resolution studies near threshold. In another experiment we measured the ionization asymmetry A(I) as function of the energy E for cesium, employing optical pumping with two laser diodes for polarizing the Cs atoms (Baum et al. 1991). The obtained A(I) (E) curve of cesium is distinctly different from those for the other alkali atoms. It displays a maximum of 0.31 at E almost-equal-to 2 . E(I) which is significantly higher than the value at threshold of 0.16. Because of this increase of A(I) with energy in the near-threshold region the Cs asymmetry is similar to that of He(2(3)S). More theoretical work is desirable