Precision magnetometry at cryogenic temperatures with gaseous 3He NMR probes

TL;DR

This paper introduces compact gaseous 3He NMR probes capable of high-precision magnetometry at cryogenic temperatures and moderate magnetic fields, achieving sensitivities suitable for various scientific applications.

Contribution

The work presents a novel gaseous 3He NMR probe design optimized for cryogenic temperatures and high magnetic fields, with enhanced relaxation properties for improved sensitivity.

Findings

Achieved magnetometry sensitivity of 10^-11 to 10^-7 in fractional field change.

Operates effectively from ambient to 4 Kelvin temperatures.

Demonstrated rapid sensor readout rates of around 1 Hz.

Abstract

We report on compact, gaseous 3He NMR probes for precision magnetometry of magnetic fields B > 0.1 T in the temperature range from ambient temperatures down to 4 Kelvin. The gas is polarized at thermal equilibrium under pressures up to 100 bar to provide a high nuclear spin density. In order to achieve sensor readout rates of order (Hz), paramagnetic substances and/or silica gel with high specific surface area were added to reduce the otherwise long T1 relaxation time of pure 3He gas to reach thermal polarization equilibrium. Sensitivity limits, which cover the range from 10-11 < dB/B < 10-7, are accessible in a single-pulse NMR measurement and can be further improved through signal averaging in accumulated NMR scans.