Detection system and method for investigating item content

An inspection system and method for inspecting the content of an article to be inspected, comprising an inspection space (10) for receiving the article (P) and a neutron beam generator (N) for generating a directed beam (B) of high-energy neutrons directed towards the inspection space. A detection device comprising at least one detector (DG, DN1... 4) is provided. A detector is responsive to interaction products from the inspection space and impinges upon substantially along a detection axis (D) when the energetic particles interact with the nucleus of the material of the article. The neutron beam generator (N) is configured to expose the inspection space (10) to a substantially unidirectional high-energy neutron beam (B) along an interrogation axis (I) through the inspection space. The cross-section of the directional bundle (B) is relatively small, in particular several times smaller than the respective cross-section of the inspection space (10), and more particularly several times smaller than the respecti