Achieving ultra-low and -uniform residual magnetic fields in a very large magnetically shielded room for fundamental physics experiments

N J Ayres; G Ban; G Bison; K Bodek; V Bondar; T Bouillaud; D Bowles; E Chanel; W Chen; P-J Chiu; C B Crawford; O Naviliat-Cuncic; C B Doorenbos; S Emmenegger; M Fertl; A Fratangelo; W C Griffith; Z D Grujic; P G Harris; K Kirch; V Kletzl; J Krempel; B Lauss; T Lefort; A Lejuez; R Li; P Mullan; S Pacura; D Pais; F M Piegsa; I Rienäcker; D Ries; G Pignol; D Rebreyend; S Roccia; D Rozpedzik; W Saenz-Arevalo; P Schmidt-Wellenburg; A Schnabel; E P Segarra; N Severijns; K Svirina; R Tavakoli Dinani; J Thorne; J Vankeirsbilck; J Voigt; N Yazdandoost; J Zejma; N Ziehl; G Zsigmond; The nEDM Collaboration At Psi

doi:10.1140/epjc/s10052-023-12351-8

Achieving ultra-low and -uniform residual magnetic fields in a very large magnetically shielded room for fundamental physics experiments

Eur Phys J C Part Fields. 2024;84(1):18. doi: 10.1140/epjc/s10052-023-12351-8. Epub 2024 Jan 8.

Authors

N J Ayres¹, G Ban², G Bison³, K Bodek⁴, V Bondar¹, T Bouillaud⁵, D Bowles⁶, E Chanel⁷, W Chen^{1

3}, P-J Chiu⁸, C B Crawford⁶, O Naviliat-Cuncic², C B Doorenbos^{1

3}, S Emmenegger¹, M Fertl⁹, A Fratangelo⁷, W C Griffith¹⁰, Z D Grujic¹¹, P G Harris¹⁰, K Kirch^{1

3}, V Kletzl^{1

3}, J Krempel¹, B Lauss³, T Lefort², A Lejuez², R Li¹², P Mullan¹, S Pacura⁴, D Pais^{1

3}, F M Piegsa⁷, I Rienäcker³, D Ries³, G Pignol⁵, D Rebreyend⁵, S Roccia⁵, D Rozpedzik⁴, W Saenz-Arevalo², P Schmidt-Wellenburg³, A Schnabel¹³, E P Segarra³, N Severijns¹², K Svirina⁵, R Tavakoli Dinani¹², J Thorne⁷, J Vankeirsbilck¹², J Voigt¹³, N Yazdandoost¹⁴, J Zejma⁴, N Ziehl¹, G Zsigmond³, The nEDM Collaboration At Psi^{1

2

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14}

Affiliations

¹ Institute for Particle Physics and Astrophysics, ETH Zürich, 8093 Zurich, Switzerland.
² Normandie Université, ENSICAEN, UNICAEN, CNRS/IN2P3, LPC Caen, 14000 Caen, France.
³ Paul Scherrer Institut, 5232 Villigen PSI, Switzerland.
⁴ Marian Smoluchowski Institute of Physics, Jagiellonian University, 30-348 Kraków, Poland.
⁵ Université Grenoble Alpes, CNRS, Grenoble INP, LPSC-IN2P3, 38026 Grenoble, France.
⁶ Department of Physics and Astronomy, University of Kentucky, Lexington, KY 40506 USA.
⁷ Laboratory for High Energy Physics and Albert Einstein Center for Fundamental Physics, University of Bern, 3012 Bern, Switzerland.
⁸ University of Zürich, 8057 Zurich, Switzerland.
⁹ Institute of Physics, Johannes Gutenberg University, 55128 Mainz, Germany.
¹⁰ Department of Physics and Astronomy, University of Sussex, Falmer, Brighton, BN1 9QH UK.
¹¹ Institute of Physics, Photonics Center, University of Belgrade, Belgrade, 11080 Serbia.
¹² Instituut voor Kern-en Stralingsfysica, University of Leuven, 3001 Leuven, Belgium.
¹³ Physikalisch-Technische Bundesanstalt, Abbestr. 2-12, 10587 Berlin, Germany.
¹⁴ Department of Chemistry-TRIGA Site, Johannes Gutenberg University Mainz, 55128 Mainz, Germany.

Abstract

High-precision searches for an electric dipole moment of the neutron (nEDM) require stable and uniform magnetic field environments. We present the recent achievements of degaussing and equilibrating the magnetically shielded room (MSR) for the n2EDM experiment at the Paul Scherrer Institute. We present the final degaussing configuration that will be used for n2EDM after numerous studies. The optimized procedure results in a residual magnetic field that has been reduced by a factor of two. The ultra-low field is achieved with the full magnetic-field-coil system, and a large vacuum vessel installed, both in the MSR. In the inner volume of $\sim 1.4 m^{3}$ , the field is now more uniform and below 300 pT. In addition, the procedure is faster and dissipates less heat into the magnetic environment, which in turn, reduces its thermal relaxation time from $12 h$ down to $1.5 h$ .