Standard Test Method for Determining Image Quality in Direct Thermal Neutron Radiographic Examination

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.

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.

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.