What is the method to identify mottling due to X-ray diffraction?

Identifying mottling due to X-ray diffraction involves noting a change between exposures while rotating the test piece. This method effectively captures variations in the radiographic image that may result from the diffraction patterns created as the X-rays interact with the material’s structure.

When the test piece is rotated, it can alter the angles at which the X-rays strike the material and subsequently how they scatter. Any noticeable changes or mottled patterns on the film or detector can indicate areas of differing density or structural variances within the material. This technique allows for enhanced detection of defects or irregularities that may not be visible from a single exposure angle.

The other choices wouldn't adequately facilitate the identification of mottling from diffraction. For instance, using different film types may yield varied sensitivity or contrast but won't directly highlight the mottling due to diffraction effects. Increasing the exposure time might enhance the overall image contrast but does not specifically target the detection of mottling. Adjusting beam energy could change the penetration of the X-rays but wouldn’t specifically help in identifying the mottled patterns caused by diffraction. Thus, rotating the test piece while determining changes in exposures is a direct and effective method for identifying such imperfections.