Thermal Properties of a Fiber-optic Radiation Sensor for Measuring Gamma-rays in High-temperature Conditions

Abstract

A fiber-optic radiation sensor (FORS) was fabricated using a cerium-doped silicate-yttriumlutetium(LYSO:Ce) scintillator crystal and a silica optical fiber (SOF) to measure gamma-raysaccurately in elevated temperature conditions. Throughout this study, a LYSO:Ce crystal wasemployed as a sensing material of the FORS due to its high light yield (32,000 photons/MeV),fast decay time ( 47 ns) and high detection efficiency. Although the LYSO:Ce crystal has manydesirable qualities, the thermoluminescence (TL) should be eliminated by using a heat annealingprocess because the light yield of the LYSO:Ce crystal varies with its TL. In this study, therefore,we obtained the TL curve of the LYSO:Ce crystal by increasing the temperature up to 280 C,and we demonstrated that almost all of the TL of the LYSO:Ce crystal was eliminated by the heatannealing process.