Generating a highly uniform magnetic field inside the magnetically shielded room of the n2EDM experiment

C. Abel; N. J. Ayres; G. Ban; G. Bison; K. Bodek; V. Bondar; T. Bouillaud; D. C. Bowles; G. L. Caratsch; E. Chanel; W. Chen; P.-J. Chiu; C. Crawford; B. Dechenaux; C. B. Doorenbos; S. Emmenegger; L. Ferraris-Bouchez; M. Fertl; P. Flaux; A. Fratangelo; D. Goupillière; W. C. Griffith; Z. Grujic; D. Höhl; M. Kasprzak; K. Kirch; V. Kletzl; S. V. Komposch; P. A. Koss; J. Krempel; B. Lauss; T. Lefort; A. Lejuez; R. Li; M. Meier; J. Menu; K. Michielsen; P. Mullan; A. Mullins; O. Naviliat-Cuncic; D. Pais; F. M. Piegsa; G. Pignol; G. Quemener; M. Rawlik; D. Rebreyend; I. Rienaecker; D. Ries; S. Roccia; D. Rozpedzik; A. Schnabel; P. Schmidt-Wellenburg; E. P. Segarra; N. Severijns; C. A. Smith; K. Svirina; R. Tavakoli; J. Thorne; S. Touati; J. Vankeirsbilck; R. Virot; J. Voigt; E. Wursten; N. Yazdandoost; J. Zejma; N. Ziehl; G. Zsigmond

doi:10.1140/epjc/s10052-025-13902-x

2024 Impact factor 4.8

Particles and Fields

Open Access

Eur. Phys. J. C (2025) 85: 202
https://doi.org/10.1140/epjc/s10052-025-13902-x

Regular Article - Experimental Physics

Generating a highly uniform magnetic field inside the magnetically shielded room of the n2EDM experiment

C. Abel¹, N. J. Ayres², G. Ban³, G. Bison⁵, K. Bodek⁶, V. Bondar², T. Bouillaud⁷^a, D. C. Bowles⁹, G. L. Caratsch²^,5, E. Chanel⁸^,20^,20, W. Chen²^,5, P.-J. Chiu²^,5^,19^,19, C. Crawford⁹, B. Dechenaux³, C. B. Doorenbos²^,5, S. Emmenegger², L. Ferraris-Bouchez⁷, M. Fertl¹⁰, P. Flaux³, A. Fratangelo⁸, D. Goupillière³, W. C. Griffith¹, Z. Grujic¹¹, D. Höhl²^,5, M. Kasprzak⁴^,14^,14, K. Kirch²^,5, V. Kletzl²^,5, S. V. Komposch²^,5, P. A. Koss⁴^,15^,15, J. Krempel², B. Lauss⁵, T. Lefort³^b, A. Lejuez³, R. Li⁴, M. Meier⁵, J. Menu⁷, K. Michielsen⁷, P. Mullan², A. Mullins⁹, O. Naviliat-Cuncic³, D. Pais²^,5, F. M. Piegsa⁸, G. Pignol⁷^c, G. Quemener³, M. Rawlik², D. Rebreyend⁷, I. Rienaecker⁵, D. Ries⁵, S. Roccia⁷, D. Rozpedzik⁶, A. Schnabel¹³, P. Schmidt-Wellenburg⁵, E. P. Segarra⁵, N. Severijns⁴, C. A. Smith⁹, K. Svirina⁷^,20^,20, R. Tavakoli⁴^,16^,16, J. Thorne⁸, S. Touati⁷, J. Vankeirsbilck⁴, R. Virot⁷, J. Voigt¹³, E. Wursten⁴^,17^,18^,17, N. Yazdandoost¹², J. Zejma⁶, N. Ziehl² and G. Zsigmond⁵

¹ Department of Physics and Astronomy, University of Sussex, Falmer, BN1 9QH, Brighton, UK
² Institute for Particle Physics and Astrophysics, ETH Zürich, 8093, Zurich, Switzerland
³ Université de Caen Normandie, ENSICAEN, CNRS/IN2P3, LPC Caen UMR6534, 14000, Caen, France
⁴ Institute for Nuclear and Radiation Physics, KU Leuven, 3001, Leuven, Belgium
⁵ Laboratory for Particle Physics, PSI Center for Neutron and Muon Sciences, Paul Scherrer Institute (PSI), Forschungsstrasse 111, 5232, Villigen, Switzerland
⁶ Marian Smoluchowski Institute of Physics, Jagiellonian University, 30-348, Cracow, Poland
⁷ LPSC, Université Grenoble Alpes, CNRS/IN2P3, Grenoble, France
⁸ University of Bern, Albert Einstein Center for Fundamental Physics, 3012, Bern, Switzerland
⁹ University of Kentucky, Lexington, USA
¹⁰ Institute of Physics, Johannes Gutenberg University, 55128, Mainz, Germany
¹¹ Institute of Physics Belgrade, University of Belgrade, 11080, Belgrade, Serbia
¹² Department of Chemistry-TRIGA Site, Johannes Gutenberg University, 55128, Mainz, Germany
¹³ Physikalisch Technische Bundesanstalt, Berlin, Germany
¹⁴ Paul Scherrer Institute, Villigen, Switzerland
¹⁵ Fraunhofer Institute for Physical Measurement Techniques, 79110, Freiburg, Germany
¹⁶ IMO-IMEC, Campus Diepenbeek, Agoralaan Gebouw D, 3590, Diepenbeek, Belgium
¹⁷ CERN, Esplanade des Particules 1, 1217, Meyrin, Switzerland
¹⁸ RIKEN, Fundamental Symmetries Laboratory, 2-1 Hirosawa, 351-0198, Wako, Saitama, Japan
¹⁹ University of Zurich, Zurich, Switzerland
²⁰ Institut Laue Langevin, Grenoble, France

^a thomas.bouillaud@epp.phys.kyushu-u.ac.jp
^b lefort@lpccaen.in2p3.fr
^c guillaume.pignol@lpsc.in2p3.fr

Received: 11 October 2024
Accepted: 3 February 2025
Published online: 20 February 2025

Abstract

We present a coil system designed to generate a highly uniform magnetic field for the n2EDM experiment at the Paul Scherrer Institute. It consists of a main $B_{0}$ $$B_0$$ coil and a set of auxiliary coils mounted on a cubic structure with a side length of $273 cm$ $273~\hbox {cm}$ , inside a large magnetically shielded room (MSR). We have assembled this system and characterized its performances with a mapping robot. The apparatus is able to generate a $1 μ T$ $1~\upmu \hbox {T}$ vertical field with a relative root mean square deviation $σ (B_{z}) / B_{z} = 3 \times 10^{- 5}$ $\sigma (B_z)/B_z = 3\times 10^{-5}$ over the volume of interest, a cylinder of radius $40 cm$ $40~\hbox {cm}$ and height $30 cm$ ${30}~\hbox {cm}$ . This level of uniformity overcomes the n2EDM requirements, allowing a measurement of the neutron Electric Dipole Moment with a sensitivity better than $1 \times 10^{- 27} e cm$ $1\times 10^{-27}e\,\hbox {cm}$ .

Present address: Institut Laue Langevin, Grenoble, France

Present address: University of Zurich, Zurich, Switzerland

Present address: Paul Scherrer Institute, Villigen, Switzerland

Present address: Fraunhofer Institute for Physical Measurement Techniques, 79110, Freiburg, Germany

Present address: IMO-IMEC, Campus Diepenbeek, Agoralaan Gebouw D, 3590, Diepenbeek, Belgium

Present address: CERN, Esplanade des Particules 1, 1217, Meyrin, Switzerland

© The Author(s) 2025

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.

Funded by SCOAP³.

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Generating a highly uniform magnetic field inside the magnetically shielded room of the n2EDM experiment

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