Crack detection flaw size parameter modeling for x-rays at grazing angle to crack faces

Nondestructive evaluation (NDE) method reliability can be determined by a statistical flaw detection study called probability of detection (POD) study. In many instances, the NDE flaw detectability is given as a flaw size such as crack length. An alternate approach is to use a more complex flaw size parameter. Earlier models by the author did not include scattering effects in detection of cracks. X-ray flaw size parameter model, given here, investigates one of scattering effects namely specular reflectivity of low energy x-rays impinging on crack faces at grazing angle. Reflectivity of x-rays at low grazing angle to crack faces is almost 100%. If crack faces are smooth and flat, the grazing angle x-rays channel between the crack faces. The paper models the specular reflection to study its effect on contrast of x-ray image. The channeling of x-rays can improve x-ray image contrast significantly. Normalized exposure and image width are used to calculate the flaw size parameter. Reflectivity of grazing angle x-rays can be used to improve x-ray crack detectability in thin low density materials.