Accessories for low-frequency hyperpolarized xenon pulsed NMR

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Nuclear magnetic resonance (NMR) is an extremely powerful analytical tool used in the fields of physics, chemistry, engineering, biology and medicine. Despite its technological and scientific importance, conventional NMR suffers from low sensitivity arising from the relatively small percentage of nuclear spins that can be polarized, even in the presence of large fields generated by superconducting magnets. In recent years it has been demonstrated that high-spin polarization may be achieved in xenon gas by a method employing intense lasers. The hyperpolarized xenon may then be used as a magnetic probe in novel NMR experiments requiring high sensitivity and/or spatial selectivity. We are pursuing one such application, namely, enhanced solid-state NMR spectroscopy of solid sample surfaces.Another advantage of a hyperpolarized magnetic probe is that experiments having acceptable signal to noise ratios may be performed in low magnetic fields that are attainable without the use of costly superconducting magnets. Here we are seeking funding for a few minor but essential components to complete our apparatus for producing hyperpolarized xenon and using it to characterize solid-state surfaces. Some items for which we are requesting funding will be used to characterize and optimize the nuclear-spin polarization, the relaxation times, and the production rate of xenon produced in a continuous-flow spin-exchange optical polarizer. The remaining items are for assembly of a low-frequency (100 kHz-1 MHz) pulsed NMR system for spectroscopy at kilogauss fields, which we will generate using a non-superconducting solenoid. The first experiment we will perform with this low-field apparatus is a hyperpolarized xenon-NMR study of the vortex phase at the surface of a high-temperature superconductor.