Neutron radiography and computed tomography are commonly used techniques to nondestructively examine materials. Tomography refers to the cross-sectional imaging of an object from either transmission or reflection data collected by illuminating the object from many different directions. Typical neutron radiography and tomography analyze transmitted images in which a large fraction of the incident radiation is transmitted through the object without collisions. Many objects have small absorption rates but large scattering rates for neutrons. The scattering properties of the material increase the probability that multiple scattered neutrons could re-enter the beam and significantly decrease image resolution. Analysis of these structures using traditional techniques is a formidable task. Classical tomography fails to reconstruct the optical properties of thick scattering objects because it does not adequately account for the scattering component of the neutron beam intensity exiting the sample. In this work, a new method of computed tomography was developed which employs an inverse problem analysis of both the transmitted and scattered images generated from a beam passing through an optically thick object. All objectives of the project were successfully met.
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