Abstract

Compton-suppression spectrometer is well suited to the analysis of low levels of radioactive nuclides. Monte Carlo simulations can be a powerful tool in calibrating these types of detector systems, provided enough physical information on the system is known. A simplified Compton-suppression spectrometer model using the Geant–4 simulation toolkit was discussed. The spectrometer model was tested to evaluate photo peak efficiency of detecting point and disk sources. The efficiency calibration was calculated for incident gamma energy from 200 to 3000 keV in both the suppressed and unsuppressed mode of operation. The applicability of the efficiency transfer method in various measurement geometries was tested successfully. It can save time and avoid tedious experimental calibration for different samples geometries.

Key words: Compton-suppression spectrometer, photopeak efficiency, Geant–4 Monte Carlo simulation Compton-suppression spectrometer, photopeak efficiency, Geant–4 Monte Carlo simulation.