Improvement study of neutron computed tomography

The images of neutron radiography (NRG) have been able to be digitally analyzed recently. Following it, neutron computed tomography (NCT) attracts people's attention of non-destructive testing field. In our laboratory, the study of NCT technology has been carried out for 5 years. We utilize NRG as a method to obtain projection data. One of the NRG's demerits is to take a long time for measuring film density, and to input it into a computer system. Then, by making use of the image input equipment, instead of micro-densitometer, the data proceeding time is amazingly shortened. This makes it possible to increase the number of projections remarkably. We made an experiment, in which the number of angular projections is 200(0.9 degree interval), at Kyoto University Reactor (KUR). The quality of obtained CT images is sufficiently good. FWHM of the line spread function for air-stainless steel was 130 μm. Resolution power was 400 μm for both air-stainless steel and aluminum-paraffin. By using image input equipment, it became easy to chase the 3-dimensional shape of an inspected object. We obtained 41 CT images for one object axially at interval of 120∼240 μm, attempted 3-dimensional reconstruction of the object. Comparing to the real object, the 3-dimensional reconstructed images were satisfactory on shape and dimension. (author)