A neutron tomographic system developed at the Rome research reactor

A third-generation neutron tomographic system, mainly used for nondestructive evaluation on small hydrogenated samples, has been recently set up at the ENEA TRIGA RC II research reactor in Rome, Italy. This reactor operates at a nominal power of 1 MW and produces a thermal beam of about 2 × 105 cm-2 s-1 with a collimation ratio L/D of about 30. The object to be examined is viewed by a Thomson CSF neutron image intensifier coupled to a cooled CCD (Charge Coupled Device) camera equipped with a sensitive array of 192 × 165 pixels, each acting as an equivalent elementary neutron detector. The entire set of projections (usually 120) needed for the examination is acquired in about 90 min, as the system operates in a rotate-only configuration with parallel beam. The reconstruction software used is a development of the Donner Package for Reconstruction Tomography, specifically modified in order to deal with third-generation algorithms using the projection images produced by the CCD camera. At present, the total reconstruction time to obtain the full set of 165 slices of 192 × 192 pixels each is about 60 min on a standard Solbourne SPARC 4 multi-user workstation. © 1994