A system and method for using the detector to differentiate neutron attenuating material from high x-ray attenuating material in an object. The inspection system is used to detect the presence of nitride in titanium sponge nuggets or residual core material in a hollow-cast turbine engine blades. The inspection system uses a dual radiation source to alternately emit neutrons and x-rays or gamma rays at the object under inspection. A dual modality gas ionization detector detects the radiation passing through the object and sends the detected radiation to a processing means for image generation. The generated image is displayed on a display, enabling objects formed with low and high attenuating material to be distinguished.