The first part of the contribution will be devoted to description of the family of Medipix/ Timepix semiconductor pixel detectors including the corresponding R/O electronics. A short demonstration of capabilities of the devices for high resolution (micrometric and nearly nanometric) radiography and 3D imaging by means of X-rays and neutrons will follow. Also the ability of Timepix pixel detectors to visualize individual particle tracks in the semiconductor sensor (solid state) similarly to nuclear emulsions, cloud chambers, bubble chamber and micro-pattern gaseous detectors will be documented. Advantages of this "particle tracking" capability will be evidenced by examples of use of the Timepix detectors for measurements of composition and spectral characteristics of mixed radiation fields around physics experiments, hadron therapy facilities, and in space research. The main part of the presentation will be dedicated to results of measurement of single neutron interactions in silicon, namely to ionizing energy depositions in a 300 μm thick silicon layer after fast neutron impact. With the Time-of-Flight (ToF) technique, the ionizing energy deposition spectra of recoiled silicon nuclei and of secondary charged particles were measured and assigned to (quasi-) monoenergetic neutron energies in the range from 180 keV to hundreds of MeV. Representative spectra will be shown and interpreted. By separating the ionizing energy losses of elastically and inelastically recoiled silicon nuclei from their energies expected from kinematics of the scattering at given neutron energy, the ratio between ionizing (IEL) and non-ionizing energy losses (NIEL) of the nuclei within the silicon lattice was determined. The data give supplementary information to the results of a previous measurement and are compared with different theoretical predictions.