Characteristics of the solid state nuclear detector CR-39 for neutron radiography purposes

The solid state nuclear track detector CR-39, together with a natural boron converter screen have been used as an image-detector system for neutron radiography purposes. In order to determine its radiographic characteristics, the image-detector system was irradiated up to neutron exposures around 6×1010 n/cm2 in a radiography facility installed at the IEA-R1 Nuclear Research Reactor. The detectors were chemically etched in a KOH (30%) aqueous solution at 70°C. The best radiography conditions were obtained for neutron exposures ranging from 1×109 to 2×1010 n/cm2 and for 25 min etching time. The present results were compared with those determined for other track detectors and discussed according to the theory of the image formation in solid state nuclear track detectors. This theory is based on the optical properties of a single track.