The invention relates to a device for identifying a material of an object having: a source of X photons and a spectrometric detector, the source irradiating the object with an incident beam and the detector measuring a magnitude of a backscattered beam from the incident beam after diffusion in a volume of the material and an energy of the X photons of the backscattered beam, the incident and backscattered beams forming an angle of diffusion (θ); a configuration for adjusting the position between the source, the detector and the object in order for the volume to be at different depths with a constant angle, a means for processing the two magnitudes in two positions and the energy in on position and for calculating an attenuation factor (μmaterial (E0, E1, ε)), a configuration for estimating the density (p) of the material.