Abstract: Method for detecting, in a load (2), the presence of objects suspected of containing at least one material having a given atomic weight, in which the load (2) is exposed to at least a first X-ray beam having a first spectrum and an atomic number class to which the materials, including the load through which the X-rays pass, is determined by high-energy discrimination. Furthermore, at least one g-ray or neutron beam spontaneously emitted by the load is measured, a spontaneous g and/or neutron radiation emission class of the material including the load is determined from the spontaneous radiation measurement, and a class of interest of the material of the load is determined from the atomic number class and the spontaneous radiation class that were determined.