Hyperpolarization of helium-3 through metastable exchange optical pumping at high pressure

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Helium-3 is an isotope of the more common element helium (helium-4) which is extracted from the nuclear decay products of tritium. Due to its odd number of nucleons, the nuclei of Helium-3 posses a magnetic moment and its gas can be polarized to a degree of several tens of % (hyper polarization). A gas of helium-3 atoms in the ground state with a high degree of nuclear polarization is highly useful for many applications in different fields such as nuclear physics, materials science, nanotechnology, quantum memory, and biophysics and medicine. In thermal equilibrium, the nuclear polarization of helium-3 induced by only applying a magnetic field is too weak to be useful for many of these applications. However, it is possible to polarize helium-3 to a high degree inside a plasma discharge through optical pumping using a continuous laser. In the so-called "metastability exchange optical pumping process" (MEOP) a nuclear polarization close to 100% can be obtained. However, the current technique operates at a very low pressure (mbar), while most applications require the use of samples of dense and highly polarized helium-3 near atmospheric pressures.The goal of this project is to achieve optimal polarization of helium-3 through MEOP near atmospheric pressure in a moderate magnetic field. This research will be done simultaneously on three fronts, taking advantage of the complementary strengths of our team: (i) the plasma discharge used to generate the helium-3 atomic metastable states that are optically pumped, (ii) relatively high magnetic fields (~ 1 Tesla), and (iii) the numerical modeling, combined with plasma diagnostics, of the excitation and polarization process taking place in the plasma. This project is a collaboration between two universities (INRS and Université de Montréal), a government organization (Atomic Energy of Canada Limited) and an industrial partner (Tyler Research Corporation) specialized in the development and commercialization of high-end medical and scientific instruments.