학술논문

Achieving ultra-low and -uniform residual magnetic fields in a very large magnetically shielded room for fundamental physics experiments
Document Type
article
Source
European Physical Journal C: Particles and Fields, Vol 84, Iss 1, Pp 1-9 (2024)
Subject
Astrophysics
QB460-466
Nuclear and particle physics. Atomic energy. Radioactivity
QC770-798
Language
English
ISSN
1434-6052
Abstract
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 $$\sim 1.4~\hbox {m}^3$$ ∼ 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 $$12~\text {h}$$ 12 h down to $$1.5~\text {h}$$ 1.5 h .