The Gamma-ray spectrometers are complex instruments and the quality of the data they provide depends strongly on their proper calibration.
This paper describes the energy and efficacy calibration of two gamma-ray spectrometers in order to validate the method for measuring the activity of gamma-ray emitting radionuclides. The punctiform
standard sources 60Co, 133Ba, 137Cs and 241Am were used in this study. Minimum Detectable Activity, Peak to Compton Ratio and the peak shape parameters were determinate.
An inter-comparison of the results obtained with both systems was done. The results demonstrated that the activity values
are comparable with low errors respecting with those for conventionally true activities.