Detecting special nuclear materials inside cargo containers using photofission

CEA is developing a method to prevent illegal traffic of special nuclear material (SNM) at borders, especially sea ports where millions of containers are transiting every day. This nondestructive method is based on the interrogation of the container by high-energy photon and the subsequent detection of particles emitted after the fission. This technique requires the knowledge of nuclear parameters that have been rarely measured for fission induced by photons. Therefore, we present fundamental measurements of these parameters for uranium-238 and uranium-235. Numerical simulations to assess the SNM detection performances are also reported.