Wavelength-resolved neutron tomography for crystalline materials

TL;DR

This paper introduces a novel algorithm for wavelength-resolved neutron tomography that effectively reconstructs crystalline materials with single-crystal domains by accounting for Bragg scattering effects, enhancing imaging capabilities.

Contribution

The paper presents a new MBIR-based algorithm that reconstructs single-crystal domain structures from WR neutron measurements, addressing challenges posed by Bragg scattering.

Findings

Successfully reconstructs single-crystal domain structures in simulated data

Identifies and excludes Bragg scatter-affected regions during reconstruction

Enhances the capability of WR neutron imaging for crystalline materials

Abstract

Wavelength-resolved (WR) neutron transmission tomography is an emerging technique to characterize engineering materials. While tomographic reconstruction for amorphous samples is straightforward, it is challenging to reconstruct samples with single-crystal domains because the attenuation of the sample varies as a function of its orientation with respect to the incident beam due to Bragg scattering. In this paper, we present an algorithm that can reconstruct samples with single-crystal domains from WR neutron tomographic measurements. In particular, we use a model-based iterative reconstruction (MBIR) technique that reconstructs the volume by identifying and leaving out the regions of the measurement that are affected by Bragg scatter. We combine the output of the MBIR method with an algorithm that matches the reconstruction to the identified Bragg scatter to reconstruct a feature that corresponds to the local crystallography of the sample being measured. Using simulated data, we demonstrate how our algorithm can reconstruct materials with single-crystal domains, thereby adding a powerful new capability for WR neutron imaging instruments.