Hyperpolarisation techniques, such as optical pumping or dynamic nuclear polarisation, are relevant for all areas where an enormous boost in nuclear polarisation is mandatory or highly desirable. This primarily includes basic and applied physics but, also, chemistry, material sciences, biology, or medicine, through the ubiquitous use of nuclear magnetic resonance (NMR) analytical tools. Polarisation enhancement factors with respect to thermal equilibrium can reach several orders of magnitude.
Hyperpolarisation of noble gas atoms by optical pumping (OP) currently enables a tremendous gain in signal in all types of research field, notably in NMR and NMR-based spectroscopy (MRS) or imaging (MRI). However commercial OP setups and most laboratory prototypes operate at low, typically millitesla, magnetic field strength. Remote polarisation and transfer into a high-field measurement system introduce complexity and losses.
The HELPING project targets innovative schemes allowing in situ hyper-polarisation of noble gases, in particular of the spin-1/2 odd isotopes: 3He for helium and 129Xe for xenon. Physicists and NMR specialists join efforts to explore new frontiers in laser OP in alkali vapours (notably high-field SEOP of 129Xe, by spin exchange with cesium atoms) and in gas discharges (notably high-field MEOP of 3He, by metastability exchange with 3He or 4He atoms in isotopic gas mixtures), as well as to launch investigations of PAMP (Polarisation of Atoms in a Magnetised Plasma), a laser-free hyperpolarisation scheme recently discovered in 3He.
Experimental, computational, and theoretical investigations are combined to advance basic knowledge and to develop, both, appropriate diagnostic tools and operational prototype devices. Measurements are performed in a super-wide bore 7 T NMR spectrometer/imager, priorly purchased by the two partners and located at NIMBE, on the CEA-Saclay campus. The instrument benefits from an advanced architecture and a broadband rf equipment suited for multi-channel spectroscopy and 3D imaging. The very large bore size allows design and test of a variety experimental setups, equipped with NMR and optical probes, for in-depth studies up to 7 T and for proof-of-concept NMR experiments with 129Xe (study of porous materials) or 3He (high-field magnetometry).
