https://doi.org/10.1140/epjc/s10052-023-12225-z
Regular Article - Experimental Physics
A large ‘Active Magnetic Shield’ for a high-precision experiment
nEDM collaboration
1
Department of Physics and Astronomy, University of Sussex, Falmer, BN1 9QH, Brighton, UK
2
ETH Zürich, Institute for Particle Physics and Astrophysics, 8093, Zurich, Switzerland
3
Normandie Univ, ENSICAEN, UNICAEN, CNRS/IN2P3, LPC Caen, 14000, Caen, France
4
Paul Scherrer Institut (PSI), 5232, Villigen, Switzerland
5
Marian Smoluchowski Institute of Physics, Jagiellonian University, 30-348, Cracow, Poland
6
LPSC, Université Grenoble Alpes, CNRS/IN2P3, Grenoble, France
7
University of Bern, Albert Einstein Center for Fundamental Physics, 3012, Bern, Switzerland
8
University of Kentucky, Lexington, USA
9
Institute of Physics, Johannes Gutenberg University, 55128, Mainz, Germany
10
Institute of Physics Belgrade, University of Belgrade, 11080, Belgrade, Serbia
11
Physikalisch Technische Bundesanstalt, Berlin, Germany
12
Institute for Nuclear and Radiation Physics, KU Leuven, 3001, Leuven, Belgium
13
Department of Chemistry-TRIGA site, Johannes Gutenberg University, 55128, Mainz, Germany
14
Institut Laue Langevin, 71 avenue des Martyrs CS 20156, 38042, Grenoble Cedex 9, France
15
University of Zurich, 8057, Zurich, Switzerland
16
Hochschule Luzern, 6002, Luzern, Switzerland
17
Fraunhofer Institute for Physical Measurement Techniques, 79110, Freiburg, Germany
18
Paul Scherrer Institut (PSI), 5232, Villigen, Switzerland
f
klaus.kirch@psi.ch
y
bondarv@phys.ethz.ch
ab
jochen.krempel@phys.ethz.ch
Received:
15
July
2023
Accepted:
6
November
2023
Published online:
20
November
2023
We present a novel Active Magnetic Shield (AMS), designed and implemented for the n2EDM experiment at the Paul Scherrer Institute. The experiment will perform a high-sensitivity search for the electric dipole moment of the neutron. Magnetic-field stability and control is of key importance for n2EDM. A large, cubic, 5 m side length, magnetically shielded room (MSR) provides a passive, quasi-static shielding-factor of about 
for its inner sensitive volume. The AMS consists of a system of eight complex, feedback-controlled compensation coils constructed on an irregular grid spanned on a volume of less than 1000 m
around the MSR. The AMS is designed to provide a stable and uniform magnetic-field environment around the MSR, while being reasonably compact. The system can compensate static and variable magnetic fields up to 
(homogeneous components) and 
(first-order gradients), suppressing them to a few 
in the sub-Hertz frequency range. The presented design concept and implementation of the AMS fulfills the requirements of the n2EDM experiment and can be useful for other applications, where magnetically silent environments are important and spatial constraints inhibit simpler geometrical solutions.
© The Author(s) 2023
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Funded by SCOAP3. SCOAP3 supports the goals of the International Year of Basic Sciences for Sustainable Development.
