The invention relates to an improved method for detecting and possibly identifying and/or characterizing nuclear and/or radiological material in a container, vehicle, or on a person, comprising the steps of: a. providing at least one detector, which is capable of detecting radiation events being interrelated to nuclear or radiological material; b. bringing the at least one detector in the vicinity of the container, vehicle or person to be monitored; c. detecting radiation events being interrelated to the container, vehicle or person to be monitored; d. assigning each detected radiation event an individual time stamp in order to generate a time pattern of the detected radiation events; and e. analyzing the time pattern with respect to time correlation structures in order to identify a presence and/or characteristics of the nuclear or radiological material.