A prerequisite to the application of MOS sensors for measurement in neutron fields is the investigation of detection of heavy ions and fission fragments using these sensors. The detection efficiency of MOS sensors for heavy ions and fission fragments depends on the angle of incidence and the energy of incident particles. Therefore, investigations were carried out for measurement of the pulse rate-voltage characteristics for different angles of incidence of heavy ions and fission fragments and for different energies of fission fragments slowed down in air. From these characteristics the angular dependence of detection efficiency and the registration threshold to the specific ionization losses of fission fragments as a function of operation voltage were determined. The experiments described in the paper were performed with129Xe ions and232Cf fission fragments.