The radiation used in radiography testing is a higher energy (shorter wavelength) version of the electromagnetic waves that we see as visible light. The radiation can come from an X-ray generator or a radioactive source.
The previous two Connect articles dealt with the defect detection techniques of MPI, LPI and eddy current testing. These methods are capable of detecting surface or very near surface imperfections and some process is therefore required to enable buried imperfections to be reliably detected – a so-called volumetric detection method. The first such method to be used in manufacturing to determine the quality of fabricated components is radiography. X-rays generated from a cathode ray tube were discovered in the late 1890’s, soon followed by the discovery of gamma radiation from radioactive isotopes.
