Author ORCID Identifier

https://orcid.org/0000-0003-1077-9292

Date Available

10-11-2022

Year of Publication

2022

Degree Name

Doctor of Philosophy (PhD)

Document Type

Doctoral Dissertation

College

Arts and Sciences

Department/School/Program

Physics and Astronomy

First Advisor

Dr. Bradley Plaster

Abstract

A permanent neutron electric dipole moment (nEDM), dn, would violate charge-conjugation and parity (CP) symmetry. The neutron electric dipole moment currently has a global limit of dn < 1.8 x 10-26 e cm (90% CL). This limit is intended to be improved by two orders of magnitude by the nEDM experiment at the Spallation Neutron Source (SNS nEDM), dn ~ 10-28 e cm. The magnetic field non-uniformities within the experimental region must be precisely monitored and managed in order to suppress systematic effects in the experiment caused by magnetic field gradients. The estimation of magnetic field components within an experimentally inaccessible zone is a challenging problem to solve, particularly in situations where direct field measurements are not feasible. To tackle this issue in the SNS nEDM experiment, a magnetic field monitoring system consisting of 39 single-axis cryogenic fluxgate magnetometer probes at discrete locations has been designed and built to provide a first-pass measurement of the field gradients within the experimental region via nondisruptive measurements of the magnetic field's components. Room-temperature tests of the system were carried out at the University of Kentucky, followed by cryogenic tests of the system at the California Institute of Technology. This dissertation will describe the theoretical framework of the magnetic field reconstruction approach and present the results of the system's preliminary tests. In addition, we propose a new method of accessing magnetic field components using physics-informed neural networks (PINNs). The new method we present will be of broad interest to experiments requiring precise determination of magnetic field components.

Digital Object Identifier (DOI)

https://doi.org/10.13023/etd.2022.364

Funding Information

This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, under Award Number DE-SC0014622.

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