Significance and Use
4.1 Radioscopy is a versatile nondestructive means for examining an object. It provides immediate information regarding the nature, size, location, and distribution of imperfections, both internal and external to the extent the exposure conditions allow. It also provides a rapid check of the dimensions, mechanical configuration, and the presence and positioning of components in a mechanism. It indicates in real-time, given spatial resolution and contrast sensitivity limitations the presence of structural or component imperfections anywhere in a mechanism or an assembly. Through manipulation, it may provide three-dimensional information regarding the nature, sizes, and relative positioning of items of interest within an object and can be further employed to check the functioning of internal mechanisms. Radioscopy permits timely assessments of product integrity and allows prompt disposition of the product based on acceptance standards. Although closely related to the radiographic method, it has much lower operating costs in terms of time, manpower, and material. Conversely, it may not be as sensitive to the detection of more subtle features as the radiographic method.
4.2 Long-term records of the radioscopic image may be obtained through motion-picture recording (cinefluorography), video recording, or “still” photographs using conventional cameras, or direct digital streaming and storage of image stacks to internal or external hard drives, or directly to RAM locations, given sufficient RAM is present in the computer. The radioscopic image may be electronically enhanced, digitized, or otherwise processed for improved visual image analysis or automatic, computer-aided analysis, or both.
4.3 Computer systems enable image or frame averaging for noise reduction. For some applications image integration or averaging is required to get the required image quality, and thus may lose their real-time responses. As an add-on, an automatic defect recognition system (ADR) may be used with the radioscopic image.
4.4 Personnel Qualification—Personnel performing examinations to this standard shall be qualified in accordance with a nationally or internationally recognized NDT personnel qualification practice or standard such as ANSI/ASNT CP-189, SNT-TC-1A, NAS 410, ISO 9712, EN 4179 or similar document and certified by the employer or certifying agency, as applicable. The practice or standard used and its applicable revision shall be identified in the contractual agreement between the using parties.
Scope
1.1 This guide is for tutorial purposes only and to outline the general principles of radioscopic imaging.
1.2 Much of the technology presented in this standard is rapidly becoming obsolete. In particular, direct viewing of phosphors or scintillators discussed is rarely used today. However, the material herein is relevant as baseline technology that has transitioned to digital technologies (See Guide E2736 for the transition to fully digital technologies).
1.3 This guide describes practices and image quality measuring systems for real-time, and near real-time, non-film detection, display, and recording of radioscopic images. Radioscopic imagery can be understood to be a live (real-time, or near real-time) presentation of X-ray radiographs that may or may not have been previously recorded. These images, used in materials examination, are generated by penetrating radiation passing through the subject material and producing an image on the detecting medium. Although the described radiation sources are specifically X-ray and gamma-ray, the general concepts can be used for other radiation sources such as neutrons. The image detection and display techniques are non-film, but the use of photographic film as a means for permanent recording of the image is not precluded.
Note 1: For information purposes, refer to Terminology E1316.
1.4 This guide summarizes the state of radioscopic technology prior to the advent of Digital Detector Arrays (DDAs), which may also be used for radioscopic imaging. For a summary of DDAs, see Guide E2736. It should be noted that some detector configurations listed herein have similar foundations to those described in Guide E2736.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For specific safety precautionary statements, see Section 6.
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
