【国外标准】 Standard Practice for Qualification of Radioscopic Systems

5.1 As with conventional radiography, radioscopic examination is broadly applicable to the many materials and object configurations which may be penetrated with X-rays or gamma rays. The high degree of variation in architecture and performance among radioscopic systems due to component selection, physical arrangement, and object variables makes it necessary to establish the performance that the selected radioscopic system is capable of achieving in specific applications. The manufacturer or integrator of the radioscopic system, as well as the user, require a common basis for determining the performance level of the radioscopic system.5.2 This practice does not purport to provide a method to measure the performance of individual radioscopic system components that are manufactured according to a variety of industry standards. This practice covers measurement of the combined performance of the radioscopic system elements when operated together as a functional radioscopic system.5.3 This practice addresses the performance of radioscopic systems in the static mode or dynamic mode, that can allow relative test-part motion between source, part, and detector, and may or may not have the ability to effect parameter changes during the radioscopic examination process. Users of radioscopy are cautioned that the dynamic aspects of radioscopy can have beneficial as well as detrimental effects upon system performance.5.4 Radioscopic system performance measured pursuant to this practice does not guarantee the level of performance which may be realized in actual operation but does provide a baseline against which periodic performance evaluations can be compared to ensure the system is operating within established limits. The effects of object-geometry and orientation-generated scattered radiation cannot be reliably predicted by a standardized examination. All radioscopic systems age and degrade in performance as a function of time. Maintenance and operator adjustments, if not correctly made, can adversely affect the performance of radioscopic systems; therefore, the system shall be re-qualified at periodic intervals (see Section 10).5.5 The performance of the radioscopic system operator in manual and semi-automatic radioscopic systems is not taken into account in this practice and can have a major effect upon radioscopic system performance. Operator qualifications and certification are an important aspect of system operation and are covered in a separate written procedure required by Practice E1255.1.1 This practice covers test and measurement details for measuring the performance of X-ray and gamma ray radioscopic systems. Radioscopy is a radiographic technique that can be used in (1) dynamic mode radioscopy to track motion or optimize radiographic parameters in real-time (25 to 30 frames per second), or both, near real-time (a few frames per second), or high speed (hundreds to thousands of frames per second) or (2) static mode radioscopy where there is no motion of the object during exposure as a filmless recording medium. This practice2 provides application details for radioscopic examination using penetrating radiation using an analog component such as an electro-optic device (for example, X-ray image intensifier (XRII) or analog camera, or both) or a Digital Detector Array (DDA) used in dynamic mode radioscopy. This practice is not to be used for static mode radioscopy using DDAs. If static radioscopy using a DDA (that is, DDA radiography) is being performed, use Practice E2698.1.1.1 This practice also may be used for Linear Detector Array (LDA) applications where an LDA uses relative perpendicular motion between the detector and component to build an image line by line.1.1.2 This practice may also be used for “flying spot” applications where a pencil beam of X-rays rasters over an object to build an image point by point.1.2 Basis of Application: 1.2.1 The requirements of this practice and Practice E1255 shall be used together. The requirements of Practice E1255 provide the minimum requirements for radioscopic examination of materials. This practice is intended as a means of initially qualifying and re-qualifying a radioscopic system for a specified application by determining its performance when operated in a static or dynamic mode. Re-qualification may require agreement between the cognizant engineering organization and the supplier, or specific direction from the cognizant engineering organization and should be addressed in the purchase order or the contract.1.2.2 System architecture including the means of radioscopic examination record archiving and the method for making the accept/reject decision are also unique system features and their effect upon system performance must be evaluated.1.2.3 This qualification procedure is intended to benchmark radioscopic system performance under selected operating conditions to provide a measure of system performance. Qualification shall not restrict operation of the radioscopic system at other radioscopic examination parameter settings, which may provide improved performance on actual examination objects. This practice neither approves nor disapproves the use of the qualified radioscopic system for the specified application. It is intended only as a standardized means of evaluating system performance.1.3 The general principles, as stated in this practice, apply broadly to transmitted-beam penetrating radiation radioscopy systems. Other radioscopic systems, such as those employing neutrons and Compton back-scattered X-ray imaging techniques, are not covered as they may involve equipment and application details unique to such systems.1.4 The user of this practice shall note that energies higher than 320 keV may require different methods than those described within this practice.1.5 This practice requires that a System Qualification Report be issued before using the system for production use.1.6 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.7 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.1.8 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.