Abstract: A scintillation detector comprising: an array of scintillation crystal elements (22); an array of detection elements (26); and a plurality of light guides (24) connecting each crystal element to multiple ones of the detection elements, so that a scintillation event in any one of the crystal elements gives rise to a signal being generated on a particular combination of the detection elements. This design allows a detection array with a relatively small number of elements, e.g. 61, to be used in conjunction with a scintillation array with a much larger number of elements, e.g. 400. High spatial resolution is thus achievable. Moreover, a high speed digital processor (28) can be used to provide rapid read out of the address of the crystal element where any scintillation event occurred.

Abstract: Different geometries of scintillation spectrometer are disclosed which provide improved resolution over prior art scintillation spectrometers. By ensuring that photons generated by scintillation events occurring in different locations within the scintillation material generate similar light profiles on the photo-detector, the output signal is made less sensitive to the initial interaction site. This can be achieved in a number of ways, such as: by limiting the exit window of the scintillation crystal to a smaller detector, by introducing an optical spacer (94) between the scintillation crystal and detector (99), and/or by making the crystal longer than necessary to stop the gamma rays. A principal advantage of these new geometries is that deconvolution of the raw-data is more effective, thus improving resolution.