Scintillator crystal readout with wavelength-shifting optical fibers

Wavelength-shifting fiber readout of scintillator crystals permits efficient discrete event localization over large scintillator areas, by flexibly interfacing position-sensitive photosensors or photosensor arrays to scintillator crystal surfaces. We describe techniques for localizing gamma-ray interactions within large crystals, and for determining the crystal of interaction within multicrystal arrays. Measurements carried out with NaI(Tl) coupled through fibers to photomultipliers confirm the technique's expected light yield, and measurements with BGO coupled through fibers to avalanche photodiodes demonstrate the usefulness of this method for crystal-of-interaction determination. We use a block detector geometry, combining fiber localization with direct energy measurement by large photomultipliers. Potential applications for gamma cameras and for high resolution PET systems are discussed.<
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