Neutron Imaging Analysis of Spin-Dependent Interactions in Ferrimagnetic Targets at Compensation Temperature

We report on a search for exotic spin-dependent interactions between neutrons and electrons possible signatures of physics beyond the Standard Model. The experiment utilizes polarized slow neutrons transmitted through a polarized electron target made of ferrimagnetic terbium-iron garnet (TbIG), maintained at its magnetic compensation temperature [1]. At this temperature, the material exhibits a high density of polarized electrons while achieving near-zero net magnetization, effectively suppressing conventional magnetic backgrounds.

Two experimental runs were conducted in 2023 and 2024 at the CG-1D Multimodal Advanced Radiography Station (MARS) on the HFIR beamline at Oak Ridge National Laboratory.

We present results based on the analysis of neutron imaging data collected during these two runs.



[1] C. D. Hughes et al., Journal of Magnetism and Magnetic Materials 629, 173273 (2025).