ASNT

PREFACE

RADIOGRAPHIC TESTING METHOD Radiographic testing has been a preeminent method of nondestructive testing since the discovery of X-rays in 1895. Film radiography in particular has been the backbone of industrial applications of penetrating radiation. It is fundamentally a very elegant analog process that provides an internal evaluation of solid objects. Although film radiography remains a widely used method of radiographic testing, many other penetrating radiation techniques for nondestructive testing have been developed and implemented. The advancements in speed and capability of digital data processing since the writing of the third edition of the radiographic testing volume have dramatically increased the application of digital methods for penetrating radiation inspections. The transition from analog to digital technology will continue into the future. This fourth edition volume of the Nondestructive Testing Handbook builds on material in the first (1959), second (1985) and third (2002) editions. The many contributors to this volume have assembled the basic body of knowledge for radiographic testing. Fundamental information in the earlier editions of the radiography volume has been maintained and enhanced, while dated or rarely used material has been dropped. The earlier editions thus remain useful references — not only for historical purposes but for material that could no longer be included in the present edition. Considerable updated information, particularly in the area of digital imaging, data processing, and digital image reconstruction, has been added in this fourth edition. Other material has been updated with recent information in such areas as radiation sources, standards, and applications. The team of contributors has tried to prepare as useful a text as possible. In many cases, items are discussed in multiple chapters to keep the continuity of the discussion in that particular chapter. This also provides multiple contexts for understanding concepts and techniques. In other cases, the handbook may rely on other chapters for details on a particular concept. The reader is encouraged to refer to the index to find information on items of interest in multiple chapters. Because of the current rate of change in technology, it is not possible to have a handbook that is completely up to date. This handbook contains the fundamental, as well as the most recent, material available at the time of its writing. Where possible, tables and figures are used to serve as a quick and ready means of finding essential technical information. The references for each chapter should be helpful for the reader seeking additional material. Readers are also encouraged to use the internet and ASNT’s website to find supplemental material on equipment and topics that are subject to change with technological advancement. It has been the pleasure of the technical editors to work with the authors and ASNT’s Nondestructive Testing Handbook staff to provide this fourth edition of the radiography handbook. We wish to thank the all the contributors, including those named in the current volume, those who provided material to the contributors and may not have been named, and those whose contributions to earlier editions have been carried over to this edition. We hope this edition proves useful as both a quick reference for technical details and a source of fundamental information for comprehensive understanding.

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