Standardization of 134Cs by three methods

The nuclide 134Cs decays by β-emission followed by γ-deexcitation to 134Ba with a half-life T1/2=2.065 a. It has been standardized by three methods: liquid scintillation counting (LSC), 4πβ–γ coincidence counting and 4πγ counting. In the LSC measurements, the CIEMAT/NIST method was used to calculate the efficiency. For the coincidence measurements, a conventional 4πβ (proportional counter)–γ(NaI) system was used. For the 4πγ standardization, a well-type NaI(Tl) detector was modeled with the Monte Carlo package PENELOPE, and the counting efficiency obtained by calculation. Results of the three methods agree within 0.65%.