Material calibration-independent neutron scattering corrections for quantitative imaging

Neutron imaging is a fundamental technique for the study of light elements, indispensable for the study of lithium distribution in batteries, water dynamics in soil or hydrogen storage in materials. Its quantitative accuracy is limited by the presence of scattered neutrons at the detector, which reduces the image contrast and introduces systematic errors in the attenuation coefficient evaluation. Here we present a dual detector setup to correct the neutron scatter component. The first detector, placed close to the sample, captures the transmitted and scattered neutrons while the second, installed downstream, captures mostly transmitted neutrons, with the scattered neutrons strongly suppressed by distance. By combining both acquisitions, we obtain a scatter-free radiography with the superior resolution of the first detector, without any sample-dependent calibration. This method is validated on a standard resolution sample to assess that there is no degradation in image quality; and the performance is proven on a highly challenging 4D tomography experiment using H ₂ O and D ₂ O mixtures within a heterogeneous soil matrix. This method brings neutron tomography from a qualitative visualisation technique to a quantitative analysis of heterogeneous, dynamic systems containing strong scattering substances.