Laser production of large nuclear-spin polarization in frozen xenon

The nuclei of gaseous ¹²⁹Xe atoms are polarized by spin exchange with optically pumped Rb vapor. The Xe gas is subsequently frozen. The nuclear polraizations of up to 25% are largely unaffected by freezing. The spin-lattice relaxation time T₁ was measured as a function of temperature, magnetic field, and isotopic composition. At 77 K and 1800 G, T₁ is limited to about 3 h by a new relaxation mechanism. The potential for accumulating large samples with even higher polarizations makes laser-polarized Xe ice promising for a wide variety of new experiments.