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

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.

Proficiency testing with uncertainty evaluation for measuring activities per unit mass of 134Cs and 137Cs in brown rice in Japan.

In Japan, we conducted proficiency testing of activity measurement by using high-purity germanium detectors for 134Cs and 137Cs in brown rice grains. Among 176 reported results, 86 % (for 134Cs) and 93 % (for 137Cs) of the results satisfied |En| â‰¦ 1. However, 58 reports for 134Cs and 51 reports for 137Cs had some failures in their evaluations of uncertainties. The proficiency testing was effective to improve the ability of uncertainty evaluation.