This thesis summarizes the results of two experimental studies of spin polarized atoms.
In the first experiments, I studied optically pumped metastable Xe atoms that were produced in glass cells with weak electrical discharges in low-pressure Xe gas. The polarization and relaxation rates of metastable 129Xe atoms are measured with magnetic resonance spectroscopy, at both microwave frequencies, where ΔF = 1 transitions are induced between the sublevels, and at radiofrequencies, corresponding to ΔF = 0 transitions. The nuclear spin polarization of the optically pumped velocity group is measured to be 22 ± 2%. The relaxation of metastable xenon atoms is dominated by depolarizing collisions with ground state atoms. We also present a model to simulate the density matrix with optical pumping and the magnetic resonances, and to use the resulting density matrix to simulate the attenuation of the optical pumping light, which provides the primary data for my studies.
The second experiments were aimed at detecting any non-linearities in the pressure shift of the hyperfine frequency of Cs atoms in Ne buffer gas. Such nonlinear shifts can be produced by the formation and breakup of CsNe Van der Waals molecules. Nonlinear shifts have been observed in the heavier buffer gases, Ar, Kr and Xe. My work shows the nonlinear part of the pressure shift from Ne is too small to be detectable with my apparatus, the most sensitive available today.
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