A tomography system at the thermal neutron column of the ENEA Casaccia TRIGA reactor

The developed system is intended for use at a collimated thermal neutron beam with a flux of about 106 n/cm2 s. The system works with a cooled CCD array (192×165 pixels) and an intensifier for light from a NE426 scintillator with traditional optical coupling. A fine mechanical regulation system allows an accurate positioning of the tomographer, also ensuring the alignment of the CCD array with the rotation and translation axes. The acquisition of 200 projections is carried out in about 30 min with a reconstruction time (40 min max) depending on the reconstruction-matrix order. Radiography and tomography of significant objects are illustrated. The reconstruction algorithm, including spatial and temporal inhomogeneity corrections and filters, was tested with good results for projections up to 512×512 pixels.