Hyperspectral Neutron CT with Material Decomposition

Thilo Balke, Charles A. Bouman, Brendt Wohlberg, Sven Vogel, Alexander Long

Abstract:

Energy resolved neutron imaging (ERNI) is an advanced neutron
radiography technique capable of non-destructively extracting
spatial isotopic information within a given material.
Energy-dependent radiography image sequences can be created
by utilizing neutron time-of-flight techniques. In combination
with uniquely characteristic isotopic neutron crosssection
spectra, isotopic areal densities can be determined on
a per-pixel basis, thus resulting in a set of areal density images
for each isotope present in the sample. By preforming
ERNI measurements over several rotational views, an isotope
decomposed 3D computed tomograpy is possible.
We demonstrate a method involving a robust and automated
background estimation based on a linear programming
formulation. The extremely high noise due to low count measurements
is overcome using a sparse coding approach. It
allows for a significant computation time improvement, from
weeks to a few hours compared to existing neutron evaluation
tools, enabling at the present stag