The Nuclotron superconducting ion synchrotron provides beams of relativistic primary (light ions) and energetic secondary particles including radioactive nuclei for wide research opportunities. Detector instrumentation is being extended to include arrays of position-sensitive semiconductor pixel detectors Timepix. Tests of irradiation with beams of deuterium, lithium and carbon have been performed and will be presented together with pixel signal response and data processing in frame of preparation for an experiment to study light nuclei fragmentation with a telescope of Timepix detectors.