Analysis of Imaging Contrast of Small Cracks in FNR Specimens

Scattering neutrons are one of the key factors which may affect the images of fast neutron radiography (FNR). We develop a math model of FNR physical process and deduce an image contrast formula that is further confirmed by comparing the results obtained by the formula with the results given by Monte Carlo simulation and experimental results. We provide a simple method to predict the image contrast in the FNR experiment.