Analytical and experimental study of the mechanisms of computing and measuring the radioactivity of the radioactive sources

In this work, we have used the basic techniques for measuring gamma rays. It is based on the use of a sodium iodide (NaI) detector withthallium activated (Tl). We have obtained:  The detector calibration NaI(Tl) and the resolution of the spectrometer.  Measuring and determining the activity of a source can be doneby using the relative, and the absolute method. The results obtained show bythe Comparison between the experimental and the theoretical(of the sources activities)a good agreement, and the best values obtained by the absolute method.