This device for processing and digitizing an energy spectrum of a radiation, comprises a charge preamplification circuit of the integrating circuit type, suitable for being connected to a semiconductor detector; a lag line energy measurement circuit connected to the output of the preamplification circuit; and a sampler connected to the output of the energy measurement circuit. It further comprises a synchronization circuit a current pulse measurement circuit connected to the output of the preamplification circuit and calculating the difference between the output and a differential of the output of the preamplification circuit; and a discrimination circuit forming a binary signal according to the output of the pulse measurement circuit said logic signal controlling the sampling times of the sampler.