Design and Experimental Field Mapping of Merritt Coil System for Polarized ³He Precision Measurements

Area of Science:

• Physics
• Atomic, Molecular & Optical Physics
• Magnetometry

Background:

• Precision measurements using polarized helium-3 (³He) are vital for magnetometry and fundamental physics.
• Magnetic field gradients can compromise measurement accuracy by reducing relaxation and coherence times.

Purpose of the Study:

• To design, model, and experimentally validate a compact four-square-coil Merritt system for uniform holding fields.
• To suppress magnetic field gradients for enhanced precision measurements of polarized ³He.

Main Methods:

• Analytical calculation of magnetic fields using vector potentials and near-center expansion.
• Modeling based on Maxwell's equations and coil system symmetries.
• Experimental characterization using a three-axis fluxgate magnetometer and motorized translation stage.

Main Results:

• The Merritt configuration demonstrates a normalized magnetic field gradient below 10⁻⁴ cm⁻¹ in the central 10 cm region.
• Measured axial field profiles closely match calculated predictions.
• The system effectively covers a 5 cm diameter and length ³He cell.

Conclusions:

• The compact Merritt system offers a practical solution for uniform magnetic fields in polarized noble-gas sensors.
• It achieves a favorable balance of gradient suppression, compactness, and mechanical simplicity.
• This technology enhances the reliability of precision measurements in magnetometry and fundamental symmetry tests.