In Search of Mirror Neutrons: Prototyping a Tri-Helical Coil with a Longitudinally Tunable Uniform Omnidirectional Field

Mirror matter is a theorized new category of particles that is a mirrored counterpart to the Standard Model and that could provide an explanation for discrepancies in experimental measurements of the neutron lifetime and insight into the nature of Dark Matter. Planned experiments for detecting mirror matter require a magnetic field that is uniform in both magnitude and direction along a neutron beamline, and also that can be oriented in any direction. To produce such a field, we designed a coil that is composed of three homogeneous solenoids, slanted by 30° and clocked by a rotation of 120° each. We also incorporated circuitry which moderates the current in each winding pair. We exploit this coil configuration to generate a B-field in any direction independent of the physical orientation of the coils by manipulating the relative current strength in the three component solenoids. By selecting specific coil winding current distributions, we increase the uniformity inside the coil. The measured field map of this prototype coil is confirmed to be consistent with the expected field simulated by Biot-Savart calculations.