A Monte Carlo evaluation of neutron images quality in a research reactor based neutron radiography facility

摘要

Neutron radiography is a useful tool for non-destructive testing of materials for research and industrial applications. Image quality assessment is an important factor that contributes to the improvement of radiographic parameters and is essential for the confirmation of the neutron radiography accuracy. The Image quality indicators (IQIs) are used for determination of the quality and sensitivity of the neutron radiographic images. In present study, the quality of the images in a neutron radiography system based on research reactor has been investigated via MCNPX Monte Carlo simulation code. Also, an experimental validation has been carried out based on using standard IQIs. The simulation results of beam purity indicator image investigation showed that the effective thermal neutron content of designed system is about 88.32% and the other malicious parameters have been obtained below 1%. The visual inspection of gaps and shims on the sensitivity indicator image determined the value of smallest gap and the value of largest visible hole. The obtained factors for IQI designation of quality level demonstrated that the neutron radiographic category of our designed and optimized system is a Category I facility.