Cryogenic magnetic coil and superconducting magnetic shield for neutron electric dipole moment searches

Abstract

A magnetic coil operated at cryogenic temperatures is used to produce spatial, relative field gradients below 6 ppm/cm, stable for several hours. The apparatus is a prototype of the magnetic components for a neutron electric dipole moment (nEDM) search, which will take place at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory using ultra-cold neutrons (UCN). That search requires a uniform magnetic field to mitigate systematic effects and obtain long polarization lifetimes for neutron spin precession measurements. This paper details upgrades to a previously described apparatus, particularly the introduction of super-conducting magnetic shielding and the associated cryogenic apparatus. The magnetic gradients observed are sufficiently low for the nEDM search at SNS.

arXiv comment26 pages, 19 figures; significant updates in response to referee comments. Reworked Section 3.2 for clarity. Added several Figures for clarity, and indicated orientation better in many Figures. Fixed typographical problems. Updated an author's attribution to reflect current place of work. Updated conclusions to better indicate future steps needed

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Cited by in corpus (5)

• Electric Dipole Moments of the Atoms, Molecules, Nuclei and Particles
• A New Cryogenic Apparatus to Search for the Neutron Electric Dipole Moment
• A $\nu$ Solution to the Strong CP Problem
• A Three-step Model for Optimizing Coil Spacings Inside Cuboid-shaped Magnetic Shields
• The neutron electric dipole moment experiment at the Spallation Neutron Source