An Introduction to Practical Industrial Tomography Techniques for Non-destructive Testing (NDT)

The IAEA promotes industrial applications of radiation technology, including advanced non-destructive testing (NDT) and non-destructive evaluation (NDE), through various coordinated research projects and regional and country level technical cooperation projects. The advanced radioisotope and radiation based NDT and NDE technologies include computed radiography (CR), digital industrial radiography (DIR) and industrial computed tomography (ICT). CR and DIR equipment is now commercially available in many companies. As it has become more standardized, compact and robust, and as its cost–benefit ratio has improved, such equipment has become more widely accessible, and many NDT centres and practitioners are now able to use CR and DIR for routine NDT practice. In contrast, the use of ICT for advanced industrial NDE is still relatively limited. One reason is that ICT is a very complex area of technology encompassing nuclear radiation detectors, mechanical engineering, computational mathematics and radiation physics. Moreover, as an imaging modality, computed tomography is entirely different from conventional projection radiography, and the specific requirements for NDE may make it prohibitively expensive for the average user at present. As a first step toward introducing this technology more widely, participants in IAEA projects have begun setting up ICT imaging systems in nuclear radiation laboratories using readily available subsystems. Such introductory level systems can then be used for training and education purposes in Member States, and the expertise gained can later be used in setting up large, complex industrial tomography facilities. The present publication is aimed at helping participating organizations in Member States and those the NDT community who are practising conventional radiography techniques to better understand the intricacies of computed industrial tomography. In particular, it provides information on various practical issues and problems relating to setting up a gamma computed tomography for NDE imaging using these simple configurations.