Pulsed NMR spectrometer with dynamic nuclear polarization for weak magnetic fields

Pulsed nuclear magnetic resonance (NMR) spectrometer operating in weak magnetic field (~100 Oe) with the dynamic nuclear polarization (DNP) is described. The spectrometer is designed to study the Overhauser DNP effect in natural hydrocarbons for potential using DNP techniques to enhance the 1H NMR signal in crude oil and petroleum products. The unit was tested on a sample of the ethylene glycol chromium complex at room temperature. A DNP enhancement of ε = −50 for 1H NMR signal from solvent protons by pumping 52Cr5+ electronic transitions with the optimized pumping parameters was achieved.