Application of high-intensity sub-MMW to the signal enhancement of nuclear magnetic resonance for biological solids

Instrumentation for high-field dynamic-nuclear polarization (DNP) was developed to enhance the sensitivity of nuclear magnetic resonance of biological solids at high magnetic fields. A newly designed gyrotron generated 394.5-GHz submillimeter wave with 40 W at the second harmonics operation. The DNP at 14.1 T was confirmed by the field dependence of
¹³
C-NMR signal amplitudes of samples at 100 K.