【国外标准】 Standard Guide for Radioscopy

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. 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 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.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, if 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. 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.1.1 This guide is for tutorial purposes only and to outline the general principles of radioscopic imaging.1.2 This guide describes practices and image quality measuring systems for real-time, and near real-time, nonfilm detection, display, and recording of radioscopic images. 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 nonfilm, 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 E1316.1.3 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 E2736, Standard Guide for Digital Detector Array Radiology. It should be noted that some detector configurations listed herein have similar foundations to those described in Guide E2736.1.4 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 and health practices and determine the applicability of regulatory limitations prior to use. For specific safety precautionary statements, see Section 6.