The behaviour of a scintillation plastic and an anthracene crystal for protons and deuterons with energies within 0,2 and 1,7 MeV. has been studied. The beam of monoenergetic particles falls directly on the detector in study in optic contact with a photomultiplicator. The impulse get in an amplifier which sends then to a scale a sting as a monitor and to an analyzer of 100 canals. The spectrum for each energy of incidental beam is obtained taking the maximum of the spectrum as the most probable value of amplitude of the detector reply, and this is represented apposite to the energy. (Author) 6 refs.