A detection system and method for investigating a content of an item to be inspected, comprising an inspection space for receiving said item and a neutron generator for generating a directional beam of energetic neutrons, directed towards said inspection space. A detector is responsive to interaction products coming from said inspection space and impinging substantially along a detection axis upon interaction of said energetic particles with nuclei of material of said item. Said neutron generator is configured to expose said inspection space to a uni-directional beam of energetic neutrons along an interrogation axis through said inspection space. Said directional beam has a smaller cross section than a corresponding cross section of said inspection space and smaller than a corresponding cross section of said item to be inspected. Said detector detects said interaction products along a detection axis upon interaction of said uni-directional beam of energetic neutrons with said item to be inspected.