【国外标准】 Standard Guide for Digital Neutron Radiography

4.1 Purpose—Practices to be employed for the radiographic examination of materials and components with neutrons using digital neutron detectors are outlined herein. They are intended as a guide for the assessment of a digital neutron radiograph’s characteristics. For information on neutron beam lines for imaging and film neutron radiography, refer to Guide E748.4.2 Limitations—Acceptance standards have not been established for any material or production process. Neutron radiography, whether performed by means of a reactor, an accelerator, subcritical assembly, or radioactive source, will be consistent in sensitivity and spatial resolution only if the consistency of all details of the technique, such as neutron source, collimation, geometry, imaging system, etc., are maintained. This guide is limited to the use of digital neutron detectors in combination with neutron conversion materials for image recording. This guide is intended for use with thermal and cold neutron spectrums. The production of thermal neutron radiographs by employing the use of film and appropriate conversion screens is covered in Guide E748.4.3 Interpretation and Acceptance Standards—Interpretat- ion and acceptance standards are not covered by this guide. Designation of accept-reject standards is recognized to be within the cognizance of product specifications.4.4 Other Aspects of the Neutron Radiographic Process—For many important aspects of neutron radiography such as technique, files, viewing of radiographs, storage of radiographs, film processing, and record keeping, refer to Guide E94, which covers these aspects for X-ray radiography. (See Section 2.)1.1 This guide covers the evaluation, qualification, and quantification of digital neutron images. These images can be acquired by many methods, including: neutron sensitive imaging plates (Computed Radiography – CR), Digital Detector Arrays – DDA’s (amorphous silicon, CMOS, CCD, etc.), micro-channel plates, neutron sensitive fluoroscopes, neutron sensitive scintillators coupled to optical cameras, digitized radiographic films, and linear diode arrays.1.2 This guide does not purport to establish what is considered an acceptable image but is intended to only give guidance on digital neutron imaging, as well as image quality metrics of importance, and how they can be measured and reported.1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.5 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.