Scintillation Detectors FEPE Determination using Volumetric Sources

Experimental determination of detector efficiency is an inflexible and a time consuming process, so the interest for computational techniques based on different principles, models, and assumptions increased during the last years. In this work the Full-Energy Peak Efficiency (FEPE) of two different NaI(Tl) scintillation detectors (2 x2 and 3 x3 ) are calculated for coaxial cylindrical sources with radii greater than the detectors faces radii. This was calculated by the effective solid angle method, taking into account the source self attenuation effect.