Liquid hyperpolarized 129Xe produced by phase exchange in a convection cell

We present a method for the production of liquid hyperpolarized 129Xe that employs spin-exchange optical pumping in the gas phase and subsequent phase exchange with a column of xenon liquid. A convection loop inside the sealed glass cell allows efficient transfer of magnetization between the gas and liquid phases. By condensing to liquid a large fraction of the sample, this scheme permits the polarization of many more 129Xe atoms in a given sealed-cell volume than would otherwise be possible. We have thus far produced a steady-state polarization of 8% in 0.1 mL of liquid with a characteristic rise time of <15 min.