Characteristics of fabricated si PIN-type radiation detectors on cooling temperature

Si PIN photodiode radiation detectors with three different active areas (3×3mm2, 5×5mm2, and 10×10mm2) were designed and fabricated at the Korea Atomic Energy Research Institute (KAERI) for low energy X- and gamma-ray detection. In Si-based semiconductor radiation detectors, one of the noise sources is thermal noise, which degrades their energy resolution performance. In this study, the temperature effects on the energy resolution were investigated using a 3×3mm2 active area PIN photodiode radiation detector using a Thermoelectric Module (TEM) from room temperature to −23°C. Energy resolutions from 25keV auger electrons to 81keV gamma-ray from a Ba-133 calibration source were measured and compared at every 10°C interval. At −23°C, energy resolutions were improved by 15.6% at 25keV, 4.0% at 31keV, and 1.2% at 81keV in comparison with resolutions at room temperature. CsI(Tl)/PIN photodiode radiation detectors were also fabricated for relatively high energy gamma-ray detection. Energy resolutions for Cs-137, Co-60, and Na-22 sources were measured and compared with the spectral responsivity.