[en] In order to improve an active type dosemeter for protection dosimetry against high-energy neutrons, characteristic response of an electronic personal dosemeter consisting of Si semiconductor detector covered with polyethylene radiator has been checked in monoenergetic neutron fields of 14.8 and 65 MeV. Pulse height distributions have been measured for several different radiator thicknesses. An analytical estimation of distributions in energy dissipated in depletion layer of Si detector has been carried out under simplified conditions. A good agreement was confirmed between both distributions in the shape and its variation with the radiator thickness and the neutron energy. The energy dependence of the dosemeter response has also been discussed. It is suggested that the energy dependence could be compensated by introducing the two-window technique with different discrimination levels on the pulse height