Design of Precision Magnetic Fields for Fundamental Neutron Symmetries

M. Higginson-Rollins[1], C. Crawford[2]
[1]Department of Electrical & Computer Engineering, University of Kentucky, Lexington, KY, USA
[2]Department of Physics & Astronomy, University of Kentucky, Lexington, KY, USA
Published in 2014

The traditionally magnetic design process involves guessing at a reasonable conductor geometry, using finite element analysis (FEA) software to calculate the resulting fields, and modifying the configuration iteratively to reach an acceptable solution. Taking the opposite approach, we developed a method of calculating the conductor geometry as a function of the desired magnetic field. This method is based on the magnetic scalar potential, which satisfies the Laplace equation, and field is specified as boundary conditions. The conductor windings follow equipotential contours of the solution on the boundary. We use LiveLink™ for MATLAB® functionality to extract these contours, convert them back as COMSOL Multiphysics® coil geometry, and simulate the resulting magnetic fields for verification. This design and validation procedure is demonstrated on a precision electromagnetic coil being developed for an experiment to measure the electric dipole moment of the neutron to a precision of 1e-28 cm.