Nuclear hyperpolarization of 3He by magnetized plasmas

Abstract

We describe a method to hyperpolarize 3He nuclear spins at high magnetic fields (4.7 Tesla) solely by a magnetized plasma. The conditions for such a magnetized plasma are fulfilled when the mean free path of the free electrons is much larger than their gyration radius in the rf gas discharge. Investigations are carried out in the 1-15 mbar pressure range with rf excitation at ~100 MHz. Quantitative NMR measurements show that for different cell sizes and 3He densities nuclear polarizations in the range 1% to 9% are observed. We explain this phenomenon by an alignment-to-orientation conversion mechanism in the excited 2 3P state of 3He which is most efficient when the Zeeman and the spin-orbit energies are comparable. The method appears as a very attractive alternative to established laser polarization techniques (spin exchange or metastability exchange optical pumping). Application to 3He nuclear magnetometry with a relative precision of 10-12 is demonstrated.

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Cited by in corpus (3)

• How to build a magnetometer with thermal atomic vapor: A tutorial
• Enhanced Polarization of Low Pressure ${}^3$He through Metastability-Exchange Optical Pumping at High Field
• Temperature-related effects in the polarization of atoms in a magnetized plasma as a promising feature towards high ${}^3$He nuclear polarization