A method of determining the radiation type and energy distribution of a radiation source that outputs radiation. The method including providing a plurality of detector materials and exposing the plurality of detector materials to the radiation. Each of the plurality of detector materials stores a signal in response to being exposed to the radiation. The signals are representative of the radiation. The plurality of detector materials is stimulated to output the signals as measured signals. These measured signals are used to determine the radiation type and energy distribution of the radiation.