The DNP experiments were performed with the recently upgraded NHMFL HiPER spectrometer , and the upgrade consists of the addition of a Keysight M9502A AWG 40 , SpecMan4EPR 3.0 for the control software , and a custom designed NMR system. The NMR instrument is composed of a single channel RF coil, with an external tuning and matching circuits following a previously established design and powered by a Direct Drive Agilent NMR console (10 -245 MHz, 250 W). Finally, the magnet is fitted with a helium flow cryostat allowing low temperature measurement compatible with the radio frequency detection system.