A method of detecting radiation from a source and a radiation detection system embodying the principles of the method are described. The method comprises: positioning a detector to receive radiation from the source; applying a multiplexing transformation to radiation from the source to create complexity in three dimensions in the pattern of radiation from the source; receiving a plurality of responses each being a response to an interaction with incident radiation occurring within the detector; determining, for each of the plurality of responses, a characteristic of the interaction, wherein the characteristic comprises at least a position in three dimensions of the interaction within the detector; processing the said plurality of responses in accordance with the determined position in three dimensions of each interaction within the detector and drawing inferences therefrom regarding the pattern of radiation from the source.

The invention relates to a combined detector (660) comprising a gamma radiation detector (100) and an X-ray radiation detector (661). The gamma radiation detector (100) comprises a gamma scintillator array (101.sub.x, y), an optical modulator (102) and a first photodetector array (103.sub.a, b) for detecting the first scintillation light generated by the gamma scintillator array (101.sub.x, y). The optical modulator (102) is disposed between the gamma scintillator array (101.sub.x, y) and the first photodetector array (103.sub.a, b) for modulating a transmission of the first scintillation light between the gamma scintillator array (101.sub.x, y) and the first photodetector array (103.sub.a, b). The optical modulator (102) comprises at least one optical modulator pixel having a cross sectional area (102′) in a plane that is perpendicular to the gamma radiation receiving direction (104). The cross sectional area of each optical modulator pixel (102′) is greater than or equal to the cross sectional area of each photodetector pixel (103′.sub.a, b).

The invention relates to a combined detector (660) comprising a gamma radiation detector (100) and an X-ray radiation detector (661). The gamma radiation detector (100) comprises a gamma scintillator array (101.sub.x, y), an optical modulator (102) and a first photodetector array (103.sub.a, b) for detecting the first scintillation light generated by the gamma scintillator array (101.sub.x, y). The optical modulator (102) is disposed between the gamma scintillator array (101.sub.x, y) and the first photodetector array (103.sub.a, b) for modulating a transmission of the first scintillation light between the gamma scintillator array (101.sub.x, y) and the first photodetector array (103.sub.a, b). The optical modulator (102) comprises at least one optical modulator pixel having a cross sectional area (102) in a plane that is perpendicular to the gamma radiation receiving direction (104). The cross sectional area of each optical modulator pixel (102) is greater than or equal to the cross sectional area of each photodetector pixel (103.sub.a, b).

A method of detecting radiation from a source and a radiation detection system embodying the principles of the method are described. The method comprises: positioning a detector to receive radiation from the source; applying a multiplexing transformation to radiation from the source to create complexity in three dimensions in the pattern of radiation from the source; receiving a plurality of responses each being a response to an interaction with incident radiation occurring within the detector; determining, for each of the plurality of responses, a characteristic of the interaction, wherein the characteristic comprises at least a position in three dimensions of the interaction within the detector; processing the said plurality of responses in accordance with the determined position in three dimensions of each interaction within the detector and drawing inferences therefrom regarding the pattern of radiation from the source.