【国外标准】 Standard Test Method for Determining Image Quality in Direct Thermal Neutron Radiographic Examination

5.1 The BPI is designed to yield quantitative information concerning neutron beam and image system parameters that contribute to film exposure and thereby affect overall image quality. In addition, the BPI can be used to verify the day-to-day consistency of the neutron radiographic quality. Gadolinium conversion screens and single-emulsion silver-halide films, exposed together in the neutron imaging beam, were used in the development and testing of the BPI. Use of alternative detection systems may produce densitometric readings that are not valid for the equations used in Section 9.5.2 The only truly valid sensitivity indicator is a reference standard part. A reference standard part is a material or component that is the same as the object being neutron radiographed except with a known standard discontinuity, inclusion, omission, or flaw. The sensitivity indicators were designed to substitute for the reference standard and provide qualitative information on hole and gap sensitivity.5.3 The number of areas or objects to be radiographed and the film acceptance standard used should be specified in the contract, purchase order, specification, or drawings.1.1 This test method covers the use of an Image Quality Indicator (IQI) system to determine the relative2 quality of radiographic images produced by direct, thermal neutron radiographic examination. The requirements expressed in this test method are not intended to control the quality level of materials and components.1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.3 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.1.4 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.