Determination of the detection efficiency of a planar HPGe detector with a non‐uniform frontal dead layer

Abstract

Peak efficiency of a non‐uniform frontal dead layer planar detector was simulated with the general purpose Monte Carlo radiation transport code PENELOPE. In a previous publication, using experimental data and an analytical model proposed by Seltzer, we found the structure and dimensions of the detectors dead layer. In this work, we used our previous results as input for a Monte Carlo simulation that considered a point source emitting specific photons from 13 to 122 keV, with the energies and emission probabilities of241Am,133Ba,207Bi,57Co,137Cs, and152Eu calibration sources, placed at 30 cm from the frontal surface of the detector. The geometry consisted of an amorphous Germanium cylinder, 2.5 cm in diameter and 1.0‐cm thick, a 0.025‐cm thick Be window and a 50‐μm Al foil used in the experimental setup for irradiations in the Microtron de São Paulo. The simulation model succeeded as well as the analytical model and can be applied to other arrangements. Copyright © 2015 John Wiley & Sons, Ltd.