Development of a neutron radiography system at the Musashi reactor

A neutron radiography (NRG) facility has been designed and installed at the one of the horizontal beam ports attached to the Musashi Institute of Technology Research Reactor (the Musashi reactor, TRIGA-II, 100 kW). For improving the neutron beam purity, the single-crystal bismuth and silicon filters were inserted into the experimental hole. The total neutron cross sections of the single-crystal bismuth and silicon were measured before installing them, and the transmission rates were also measured. The structure was varied by using the cylindrical collimators of lead and polyethylene with different inner-diameters. The optimum structure was determined, after the neutron flux and gamma-ray doses were measured with the various structures. The result of resolution measurements for the Image Quality Indicators (IQI) satisfied the grade 1 values of ASTM E545-81 category using a vacuum cassette with a metallic gadolinium converter. Various combinations of the converters and X-ray films were examined in order to obtain a high-quality photograph. An X-ray radiography (XRG) apparatus using a portable generator was also equipped for the comparison with the NRG. A real-time NRG has also been installed for the investigation of moving objects and for the study of a neutron computed tomography (NCT). A high-quality radiographic image was obtained by an image orthicon camera and a digital image processing system. (author)