A Far Ultraviolet Polarization Analyzer for Rocket Use

A rocket version of a far uv polarization analyzer has been constructed to measure the polarization of resonantly scattered sunlight. The rotating, eight-plate, LiF polarization analyzer has principal transmittances which vary from k(1) = 0.088 and k(2) = 0.0037 at H Lyman-alpha to k(1) = 0.623 and k(2) = 0.075 at 2500 A. The region from 1200 A to 2000 A is divided into four intervals by using filters of CaF(2), BaF(2), and Al(2)O(3) in conjunction with the solar blindness of the CsI photocathode. The calculated polarizations, which are a direct consequence of the Zeeman effect, are given for some of the uv multiplets which could contribute to the uv day airglow in planetary atmospheres. Departures from the calculated polarizations may be due to the effects of multiple scattering, collisional excitation, and hyperfine structure. The observed polarization of the sum of the lines which constitute a multiplet is dependent upon the relative population (a measure of the temperature) of the ground states of the multiplet.