Calculation and Experiment of Detective Efficiency of LaBr₃：Ce Scintillation Detector

The absorption efficiency and peak-to-total ratio of LaBr₃：Ce scintillators in different sizes were calculated by the Monte-Carlo method. The detection efficiency of a 50 mm×10 mm LaBr₃：Ce detector was calibrated using three point sources ¹³⁷Cs, ⁶⁰Co and ¹⁵²Eu. The calculation result shows a good agreement with the experiment result. The efficiency curve of the LaBr₃：Ce detector to γ rays from 0 to 10 MeV was given by combining the calculation results with the experiment results. In this way, the detect efficiency of LaBr₃：Ce detector could be acquired even there are not enough γ sources for calibration.