SQUID detected NMR of laser-polarized xenon at 4.2 K and at frequencies down to 200 Hz

A spectrometer based on a dc SQUID (superconducting quantum interference device) was used to record nuclear magnetic resonance signals from laser-polarized 129Xe at 4.2 K and at frequencies ranging from about 200 Hz to 110 kHz in magnetic fields varying from about 0.02 to 9 mT. The 129Xe resonance linewidths were found to increase with increasing magnetic field, and, at a given field, to increase with higher 129Xe concentration. The spin-lattice relaxation times were observed to decrease from ∼ 8000 s at 5 mT to ∼ 2000 s at fields below 0.05 mT. Such long relaxation times make possible a variety of spin polarization transfer experiments.