Topological phononic crystal as a neutron detector

Purpose This study explores the use of one-dimensional topological phononic crystals (1D TPnCs) as novel platforms for neutron flux sensing. By exploiting topologically protected edge states, which are resilient to defects and perturbations, the aim is to develop highly sensitive and low-threshold neutron detectors based on changes in elastic properties induced by irradiation.
Methods The proposed TPnC is composed of two one-dimensional phononic crystals made of epoxy and concrete layers with differing thicknesses, forming a heterostructure that supports edge modes. The transfer matrix method is applied to calculate transmission spectra of acoustic waves through the structure. Neutron irradiation effects are modeled as reductions in the Young’s modulus of concrete, and both sensitivity and limit of detection (LOD) are evaluated based on the shift in resonance frequency of the topological edge state.
Results A distinct topological edge state emerges within the first phononic band gap, with its resonance frequency decreasing as neutron flux increases. This frequency shift is attributed to the radiation-induced softening of concrete. The sensor demonstrates enhanced sensitivity with increasing neutron exposure. However, a concurrent broadening of the resonance peak (FWHM) slightly degrades the resolution. The minimum detectable change in neutron flux was approximately 4.7% under specific irradiation conditions.
Conclusion The study demonstrates, for the first time, that 1D TPnCs based on Bragg reflector principles can serve as effective neutron flux detectors. Their edge modes offer strong localization and robustness, resulting in high sensitivity to irradiation-induced material changes. These findings open new avenues for the integration of topological mechanics into radiation sensing technologies.