Dramatic improvement in the "Bulk" hyperpolarization of Xe via spin exchange optical pumping probed using in situ low-field NMR.

We report on hyperpolarization of quadrupolar (I=3/2) Xe via spin-exchange optical pumping. Observations of the Xe polarization dynamics via in situ low-field NMR show that the estimated alkali-metal/Xe spin-exchange rates can be large enough to compete with Xe spin relaxation. Xe polarization up to 7.