Assembly and performance of a 6.4 T cryogen-free dynamic nuclear polarization system #DNPNMR
 

From The DNP-NMR Blog:

Assembly and performance of a 6.4 T cryogen-free dynamic nuclear polarization system #DNPNMR

Kiswandhi, Andhika, Peter Niedbalski, Christopher Parish, Qing Wang, and Lloyd Lumata. “Assembly and Performance of a 6.4 T Cryogen-Free Dynamic Nuclear Polarization System.” Magnetic Resonance in Chemistry 55, no. 9 (2017): 846–52.


https://doi.org/10.1002/mrc.4624.


We report on the assembly and performance evaluation of a 180-GHz/6.4 T dynamic nuclear polarization (DNP) system based on a cryogen-free superconducting magnet. The DNP system utilizes a variable-field superconducting magnet that can be ramped up to 9 T and equipped with cryocoolers that can cool the sample space with the DNP assembly down to 1.8 K via the Joule–Thomson effect. A homebuilt DNP probe insert with top-tuned nuclear magnetic resonance coil and microwave port was incorporated into the sample space in which the effective sample temperature is approximately 1.9 K when a 180-GHz microwave source is on during DNP operation. 13C DNP of [1-13C] acetate samples doped with trityl OX063 and 4-oxo-TEMPO in this system have resulted in solid-state 13C polarization levels of 58 ± 3% and 18 ± 2%, respectively. The relatively high 13C polarization levels achieved in this work have demonstrated that the use of a cryogen-free superconducting magnet for 13C DNP is feasible and in fact, relatively efficient—a major leap to offset the high cost of liquid helium consumption in DNP experiments.


Go to The DNP-NMR Blog for more info.