Patent ID: 8299441

Claim:
A directional gamma radiation detector system for determining an angle under which a measured gamma radiation hits a gamma radiation detector system, comprises: at least two gamma radiation detectors arranged in close distance; detector electronics for operating the at least two gamma radiation detectors as spectrometers in a way that the detector electronics are collecting energy spectra of the detected gamma rays for each gamma radiation detector; and system electronics allowing the directional gamma radiation detector system to identify coincident events in the at least two gamma radiation detectors and set to conduct at least the following steps: collecting an energy spectrum E 20 of the detected gamma rays in a first one of the at least two gamma radiation detectors by the corresponding detector electronics ( 250 ), limited to coincident events in a second one of the gamma radiation detectors, collecting an energy spectrum E 30 of the detected coincident gamma rays in the second gamma radiation detector by the corresponding detector electronics ( 350 ), determining a mean energy <E 20 > of the first energy spectrum E 20 , determining a mean energy <E 30 > of the second energy spectrum E 30 , and determining the angle under which the measured gamma radiation hits the gamma radiation detector system by comparing the mean energy <E 20 > with the mean energy <E 30 >.