Daniel Walter

High‐volume production of laser‐polarized 129Xe

A method is described for producing several liters of nuclear spin polarized 129Xe gas via spin exchange with an optically pumped Rb vapor. We use a 140 W AlGaAs laser diode array whose broad spectral output is efficiently absorbed by employing ∼10 atm of 4He to pressure broaden the Rb D1 absorption profile. 129Xe is polarized in a continuous gas flow and is then cryogenically accumulated and stored. Extensions of this technique should enable the production of tens of liters of 129Xe with a nuclear spin polarization of order 50%. Production of laser‐polarized 129Xe in liter quantities is important for the continued development of magnetic resonance imaging using spin‐polarized 129Xe.

Magnetic resonance imaging of hyperpolarized 129Xe produced by spin exchange with diode-laser pumped Cs

We report the results of experiments leading to the production of an image of a polarized 129Xe sample prepared by spin exchange with Cs, optically pumped with a spectrally narrowed 894.3 nm diode laser. Representative images of the average electron spin polarization are shown. Appreciable cesium electron polarization values were achieved, and a nuclear polarization of about 2.5% was measured for 129Xe. The absolute nuclear polarization was measured by water-calibrated free induction decay of the nuclear magnetic resonance signal, and the polarized xenon imaged using a 2 T magnetic resonance imaging system.