Calculation of full-energy peak efficiency of NaI (Tl) detectors by new analytical approach for parallelepiped sources

A new analytical approach is presented for the calculation of full-energy peak (FEP) efficiency of NaI (Tl) detectors.The self-attenuation of the parallelepiped source matrix, the attenuation by the source container, and the detectorhousing materials were considered in the mathematical treatment. The efficiency values calculated using thepresently suggested analytical approach are compared with those measured values obtained by two different sizesof NaI (Tl) detectors. The calculated and the measured full-energy peak efficiency values were in a good agreement.