Optimisation of fast-neutron radiography by using a new imaging quality concept

A new method is proposed for the quality assessment of a neutron radiographic image. The quality of visualisation can be expressed as a Figure of Merit (FOM) defined as the image contrast in terms of the statistical uncertainty. The FOM enables optimisation of the image contrast of the object under investigation by changing the instrument or object characteristics. The FOM is used to investigate the influence of background countrate due to unwanted events or scattered neutrons by both analytical calculations and Monte-Carlo simulations.