Fast neutron radiography (FNR) using divergent neutron beams has the characteristic to magnify small cracks in low-Z materials. For such magnifying FNR systems, a simple method was developed using Monte Carlo simulations to estimate the spatial resolution. The resolution degrading factors, including neutron source size, object thickness, and crosstalk in the detector, have been investigated in this method. The calculated results of this method compare favorably to independent estimations of various designs for the same FNR system. For a magnifying FNR system, a better spatial resolution can be expected with larger magnifications and smaller sources.

Neutron/x-ray combined radiography can integrate the merits of x-ray and neutron radiography and have an enhanced non-destructive detecting capability compared to single neutron or x-ray radiography. In this work, magnifying neutron/x-ray combined radiography along the same line of sight was performed at the Shenguang (SG) laser facility for the first time. Based on [Formula: see text] mm point-like backlight sources of neutrons and x rays, structural defects on the order of ∼0.2 mm within polyethylene and Fe were observed in neutron and x-ray radiography, respectively. In addition, the spatial resolution obtained was 0.68 ∼ 2.05 mm in the object position for neutron radiography and ∼0.14 mm for x-ray radiography. This indicated that the combined radiography system arranged along the same line of sight at the SG laser facility possessed the ability to inspect structural defects within both low-Z and high-Z materials simultaneously, with relatively high spatial resolution.