Geant4 simulation study and experimental verification of fast neutron radiography system based on 600 kV pulsed neutron generator

Fast neutron radiography (FNR) is a non-destructive radiographic inspection technique, which has significant advantages in the field of non-destructive quality inspection of large-size and high-density materials. We have previously developed an FNR system based on a 600 kV pulsed neutron generator. In this study, we used Geant4 Monte Carlo simulation software to model the FNR system. The performance of the collimator was evaluated through simulation analysis. We comparatively analysed the imaging parameters for different conversion screen thicknesses and detection distances, in order to select the optimal conversion screen thickness and detection distance for the experimental design. Simulated imaging and experimental radiography were carried out on both the lead slit sample and the iron square-hole sample, respectively, demonstrating good agreement between the simulated and experimental images. Furthermore, by comparing experimental radiographs of lead slit samples with varying thicknesses, we analysed the influence of sample thickness on spatial resolution. These findings will be valuable for the future experimental design and application research of FNR systems.