[en] Elastic scattering of light nuclei, especially hydrogen, is widely used for the detection of fast neutrons. The fast neutron is detected in state nuclear track detectors (SSNTDs), such as CR-39, through interactions with H, C and O nuclei. The fast-neutron response can be increased by using a converter layer with high hydrogen content, if the front face of the dosimeter is being processed. In this work, only elastic scattering of hydrogen has been considered, and the optimum thickness of the converter layer has been determined. Some different thicknesses of aluminium layers have been used as discriminators for which the efficiency of a detector to a ²⁴¹Am-Be neutron source has been calculated. A program FTRAC has been developed for the calculation of the detection efficiency. This software determines the specifications of recoil protons (using the PTRAC card of the MCNP code) and also the kinematics of interactions. Transport of recoiled protons has been carried out using SRIM code. Good agreement have been shown between measurement and simulation result