Apparatus for the simultaneous selective detection of neutrons and X or gamma photons and detection system using said apparatus

Apparatus for the simultaneous selective detection of neutrons and X or gamma photons said apparatus comprising a detector incorporating:

• a first scintillator (2) which is sensitive to neutrons and which does not produce X or gamma photons by interaction with said neutrons and a second scintillator (4) sensitive to X or gamma photons, said detector being associated with a photomultiplier means (14), characterized in that the second scintillator (4) is organic and monocrystalline, in that the detector includes a guidance and attenuation means (6) for guiding to the photomultiplier means (14) the scintillations which are produced by the first scintillator (2) under the impact of neutrons and for reducing the intensity of the radiation constituted by said scintillations, said guidance and attenuation means thus lowering the energy of the amplitude spectrum of the scintillations due to the neutrons, said amplitude spectrum being supplied by the photomultiplier means and in that the first scintillator (2), the second scintillator (4) and the guidance and attenuation means (6) are chosen such that the peak of the scintillations due to the neutrons and the photoelectric peak of the scintillations due to the X or gamma photons are in energy bands clearly separated from one another and from the electronic background noise of the photomultiplier means.