Figure 1: Continuously re-hyperpolarized 1H-MR signal extending for more than 700 s.
Absolute polarization produced during the continuous hyperpolarization process. Each data point represents the peak area of a hyperpolarized pyridine resonance as monitored by a cascade of 90° excitation pulses that are separated by a variable recovery delay (TR/s); quantification is based on the signal from a thermally polarized water sample at 5 mT. After depletion by excitation, the hyperpolarization level recovers with a time constant of 5 s to a level of 10−3, which equates with a thermal 1H-polarization field of between 102 and 103 Tesla. The estimated concentration of H2 in this solution is 4 mM.
