Ultrasensitive 3He magnetometer for measurements of high magnetic fields

TL;DR

This paper introduces an ultrasensitive 3He magnetometer capable of measuring high magnetic fields with exceptional accuracy, utilizing long spin precession times and innovative polarization techniques.

Contribution

The paper presents a novel 3He magnetometer design that achieves high precision in strong magnetic fields through enhanced spin coherence and a new polarization method.

Findings

Achieves measurement accuracy better than 10^-12 in magnetic fields over 0.1 Tesla.

Long spin precession times of minutes improve sensitivity.

Miniaturization further enhances coherence time without sensitivity loss.

Abstract

We describe a 3He magnetometer capable to measure high magnetic fields (B > 0.1 Tesla) with a relative accuracy of better than 10^-12. Our approach is based on the measurement of the free induction decay of gaseous, nuclear spin polarized 3He following a resonant radio frequency pulse excitation. The measurement sensitivity can be attributed to the long coherent spin precession time T2* being of order minutes which is achieved for spherical sample cells in the regime of motional narrowing where the disturbing influence of field inhomogeneities is strongly suppressed. The 3He gas is spin polarized in-situ using a new, non-standard variant of the metastability exchange optical pumping. We show that miniaturization helps to increase T2* further and that the measurement sensitivity is not significantly affected by temporal field fluctuations of order 10^-4.