Normal nuclear magnetic resonance (NMR) probes cannot be used to make high frequency resolution measurements in a cryogenic environment because they lose their frequency resolution when the liquid sample in the probe freezes. A gaseous 3He NMR probe, designed and constructed to work naturally in such cryogenic environments, is demonstrated at 4.2 K and 5.3 Tesla to have a frequency resolution better than 0.4 part per billion. As a demonstration of its usefulness, the cryogenic probe is used to shim a superconducting solenoid with a cryogenic interior to produce a magnetic field with a high spatial homogeneity, and to measure the magnetic field stability.
@article{arxiv.1904.04804,
title = {Gaseous $^3$He Nuclear Magnetic Resonance Probe for Cryogenic Environments},
author = {X. Fan and S. E. Fayer and G. Gabrielse},
journal= {arXiv preprint arXiv:1904.04804},
year = {2023}
}