Large Magnetic Shielding Factor Measured by Nonlinear Magneto-optical Rotation

TL;DR

This paper reports the measurement of a large axial magnetic shielding factor of approximately 1.3×10^7 using a nonlinear magneto-optical rotation magnetometer, relevant for neutron EDM experiments.

Contribution

The study demonstrates a novel measurement of high magnetic shielding factor using nonlinear magneto-optical rotation with a paraffin-coated Rb vapor cell.

Findings

Measured axial shielding factor of (1.3±0.1)×10^7

Used nonlinear magneto-optical rotation technique

Achieved measurement at room temperature

Abstract

A passive magnetic shield was designed and constructed for magnetometer tests for the future neutron electric dipole moment experiment at TRIUMF. The axial shielding factor of the magnetic shield was measured using a magnetometer based on non-linear magneto-optical rotation of the plane of polarized laser light upon passage through a paraffin-coated vapour cell containing natural Rb at room temperature. The laser was tuned to the Rb D1 line, near the $^{85}$Rb $F=2\rightarrow 2,3$ transition. The shielding factor was measured by applying an axial field externally and measuring the magnetic field internally using the magnetometer. The axial shielding factor was determined to be $(1.3\pm 0.1)\times 10^{7}$, from an applied axial field of 1.45~$\mu$T in the background of Earth's magnetic field.