Neutron radiography with Kyoto university research reactor, (3)

The image evaluation of neutron radiographic photographs was studied by use of sensitivity indicators developed by the authors. They are constructed by a combination of a wire type indicator having nylon wires with 7 different diameters and a bacillus type indicator having 30 nylon wires with the same diameter and the length. From the neutron radiographic photographs, the detectable minimum diameters were determined. For this experiment, fine ceramics plates and copper plates were employed as samples. It has been found that the detectable minimum diameters of nylon wires obtained by the two types of indicators are nearly equal at the bacillus sensitivity of 50 %. The fault sensitivity obtained by the sensitivity indicators were below 1 % of the thickness of the samples. (author)