Hautle, P., and W.Th. Wenckebach. “Creating High, Portable Proton Polarization with Photo-Excited Triplet DNP.” Journal of Magnetic Resonance Open 20 (September 2024): 100159.
https://doi.org/10.1016/j.jmro.2024.100159.
Dynamic nuclear polarization (DNP) is a powerful tool to polarize nuclear spins and enhance the intensity of their magnetic resonance signal. For DNP a sample is doped with an agent providing unpaired electron spins. Then the sample is cooled in a strong magnetic field to polarize these electron spins and a microwave field is applied to transfer this polarization to the nuclear spins. While DNP is very efficient, it has two inherent issues: the electron spins needed to polarize the nuclear spins are also the main source of polarization decay. Furthermore, polarizing the electron spins requires strong magnets and powerful cryogenics, that may obstruct further use of the polarized nuclear spins.