A NEUTRON TOMOGRAPHIC SYSTEM DEVELOPED AT THE ROME RESEARCH REACTOR

A third-generation neutron tomographic system, mainly used for nondest ructive evaluation on small hydrogenated samples, has been recently se t up at the ENEA TRIGA RC II research reactor in Pome, Italy. This rea ctor operates at a nominal power of 1 MW and produces a thermal beam o f about 2 x 10(5) cm(-2) s(-1) with a collimation ratio L/D of about 3 0. The object to be examined is viewed by a Thomson CSF neutron image intensifier coupled to a cooled CCD (Charge Coupled Device) camera equ ipped with a sensitive array of 192 x 165 pixels, each acting as an eq uivalent elementary neutron detector. The entire set of projections (u sually 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 Pack age for Reconstruction Tomography, specifically modified in order to d eal with third-generation algorithms using the projection images produ ced by the CCD camera. At present, the total reconstruction time to ob tain the full set of 165 slices of 192 x 192 pixels each is about 60 m in on a standard Solbourne SPARC 4 multi-user workstation.