Estimation of 134Cs activity by a new approximation referred to the sum-peak method via a well-type Ge detector

Highlights: • A new approximation was applied to estimate ¹³⁴Cs activity via well-type Ge detector. • The new calculation is referred to the sum-peak method. • The source contained ¹³⁴Cs and/or ¹³⁷Cs. • The activity estimated by this technique agreed well with the certified activity. - Abstract: The activity of a sample containing ¹³⁴Cs and ¹³⁷Cs was estimated by means of a new approximation referred to the sum-peak method using a well-type Ge detector. The contribution of ¹³⁷Cs to the total count rate was estimated from its peak count rate, and subtracted from the total count rate. Then the total count rate originating from ¹³⁴Cs was estimated. Finally, the new method was applied and the ¹³⁴Cs activity was estimated.