A Universal Method to Generate Hyperpolarisation in Beams and Samples

TL;DR

This paper introduces a simple, theoretically supported method using radio-wave induced quantum interference to generate significant hyperpolarisation in nuclear spins, applicable to samples at rest and beams, with potential in MRI and nuclear fusion.

Contribution

It presents a novel, easier technique for hyperpolarisation based on quantum interference, demonstrated experimentally for hydrogen beams and applicable to various samples.

Findings

Large hyperpolarisation achieved at low magnetic fields

Method proven experimentally for metastable hydrogen beams

Potential applications in low-field MRI and fusion fuel production

Abstract

Sizable hyperpolarisation, i.e. an imbalance of the occupation numbers of nuclear spins in a sample deviating from thermal equilibrium, is needed in various fields of science. For example, hyperpolarised tracers are utilised in magnetic resonance imaging in medicine (MRI) and polarised beams and targets are employed in nuclear physics to study the spin dependence of nuclear forces. Here we show that the quantum interference of transitions induced by radio-wave pumping with longitudinal and radial pulses are able to produce large polarisations at small magnetic fields. This method is easier than established methods, theoretically understood and experimentally proven for beams of metastable hydrogen atoms in the keV energy range. It should also work for a variety of samples at rest. Thus, this technique opens the door for a new generation of polarised tracers, possibly low-field MRI with better spatial resolution or the production of polarised fuel to increase the efficiency of fusion reactors by manipulating the involved cross sections.