Eur. Phys. J. D (2015) 69: 202
https://doi.org/10.1140/epjd/e2015-60018-7

Regular Article

Design and performance of an absolute ³He/Cs magnetometer

¹ Physics Department, University of Fribourg, 1700 Fribourg, Switzerland
² Department of Physics, Johannes Gutenberg-University, 55122 Mainz, Germany
³ Paul Scherrer Institute, 5232 Villigen, Switzerland
⁴ Physikalisch-Technische Bundesanstalt Institut, 10587 Berlin, Germany
⁵ Ioffe Physical Technical Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia

^a e-mail: kochhc@googlemail.com
^b Present address: LogrusData, Vienna, Austria

Received: 9 January 2015
Received in final form: 20 June 2015
Published online: 21 August 2015

Abstract

We report on the design and performance of a highly sensitive combined ³He/Cs magnetometer for the absolute measurement of magnetic fields. The magnetometer relies on the magnetometric detection of the free spin precession of nuclear spin polarized ³He gas by optically pumped cesium magnetometers. We plan to deploy this type of combined magnetometer in an experiment searching for a permanent electric dipole moment of ultracold neutrons at the Paul-Scherrer Institute (Switzerland). A prototype magnetometer was built at the University of Fribourg (Switzerland) and tested at Physikalisch-Technische Bundesanstalt (Berlin, Germany). We demonstrate that the combined magnetometer allows Cramér-Rao- limited field determinations with recording times in the range of , measurements above being limited by the stability of the applied magnetic field. With a recording time we were able to perform an absolute measurement of a magnetic field of ≈ with a standard uncertainty of , corresponding to ΔB/B< 6 ×10^-8.