PERFORMANCE OF LARGE-VOLUME CSI(TL) SCINTILLATORS COUPLED TO SILICON PHOTODIODES IN GAMMA-RAY SPECTROSCOPY

For many years researchers have tried to replace the photomultiplier t ube by a solid state photodiode in scintillation probes. Silicon avala nche diodes have first been investigated, but high sensitivity to any temperature changes limited their use. Conventional silicon-based phot odiodes are manufactured by using high resistivity silicon and planar technology, and have opened new possibilities involving the use of com pact scintillation probes operating at very low bias with current dens ities in the order of 1 nA/cm(2). Gamma ray spectrometers have recentl y been built that couple 1 cm(2) silicon photodiodes to small scintill ators. We discuss the possibility of using similar photodiodes in conj unction with much larger scintillators (up to 2 in. in diameter and 2 in. in height) in gamma-ray spectroscopy. Their superior performance i s discussed, along with the effects of electronic noise, gamma-ray ene rgy and mode of coupling.