Detection of ionising radiation

A detector for detecting ionising radiation, comprising:

• a scintillator selected to emit light in response to incident radiation;
• at least one detector for detecting the emitted light;
• a plurality of optical waveguides, the plurality of optical waveguides disposed orthogonally in rows and columns and for transmitting the emitted light to the detector, wherein each of the plurality of optical waveguides comprises a hollow optical fibre containing a replaceable scintillator material in the hollow of the optical fibre,
• at least one manifold configured to selectively introduce and withdraw different scintillator materials from the plurality of optical waveguides to adapt the detector for detecting radiation of different types;
• and
• a processor configured to receive output from the at least one detector and control the introduction and withdrawal of the different scintillator materials from the plurality of optical waveguides based on different types of radiation.