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A table-top PXI based low-field spectrometer for solution dynamic nuclear polarization



Joshua R. Biller, Karl F. Stupic, John M. Moreland


We present the development of a portable dynamic nuclear polarization (DNP) instrument based on the PCI eXtensions for Instrumentation platform. The main purpose of the instrument is for study of 1H polarization enhancements in solution through the Overhauser mechanism at low magnetic fields. A DNP probe set was constructed for use at 6.7 mT, using a modified Alderman-Grant resonator at 241 MHz for saturation of the electron transition. The solenoid for detection of the enhanced 1H signal at 288 kHz was constructed with Litz wire. The largest observed 1H enhancements (ε) at 6.7 mT for 14N‐CTPO radical in air saturated aqueous solution was ε~65. A concentration dependence of the enhancement is observed, with maximum ε at 5.5 mM. A low resonator efficiency for saturation of the electron paramagnetic resonance transition results in a decrease in ε for the 10.3 mM sample. At high incident powers (42 W) and long pump times, capacitor heating effects can also decrease the enhancement. The core unit and program described here could be easily adopted for multi‐frequency DNP work, depending on available main magnets and selection of the "plug and play" arbitrary waveform generator, digitizer, and radiofrequency synthesizer PCI eXtensions for Instrumentatione cards.
Journal of Magnetic Resonance


DNP, PXI, Low-field, 1H, Hyperpolarization, LabVIEW, Nitroxide, Resonator efficiency


Biller, J. , Stupic, K. and Moreland, J. (2017), A table-top PXI based low-field spectrometer for solution dynamic nuclear polarization, Journal of Magnetic Resonance, [online], (Accessed April 24, 2024)
Created October 4, 2017, Updated January 5, 2018