Use of the Compton scatter spectrometry technique in non-destructive evaluation of engineering components

Non-destructive testing of engineering components is a prime requirement of a quality control programme before putting them into service. Several techniques are available for non-destructive inspection, such as radiography, ultrasonic testing, eddy current testing and magnetic flaw detection. In all the techniques, scanning energy, in different forms such as electromagnetic waves, ultrasound waves, electrical energy, polarised light, is applied to the component under test and their interaction with a flaw is recorded and later this signal is analysed to extract information. It is known that each technique has its limitations. For example, magnetic particle inspection is limited to ferromagnetic material, eddy current testing is applicable to electrically conducting materials, radiography is less sensitive in detecting planar flaws. Therefore, newer methods are emerging in the field of non-destructive inspection technology for specific requirements. Infrared thermography, holography, neutron radiography, Compton scatter spectrometry are all such techniques. In the Compton scatter technique, material is scanned with a photon beam. It is known when an X-ray or gamma-ray impinges on a target material that some of the photons are scattered and deviate from their initial path. This Compton scattered radiation provides useful information. In this paper, the use of Compton scatter radiation for the non-destructive evaluation of materials has been explored.