Application of beta coincidence to nuclide identification of radioactive samples contaminated by the accident at the Fukushima Nuclear Power Plant determination in a mixture of Cs-137 and Cs-134; beta emitters; plastic scintillation detector; NaI(Tl) scin

We proposed a new method to determine the activity of each nuclide in a mixture of Cs-134, Cs-137 and Sr/Y-90. The point of this new measurement method is simultaneous counting between beta and gamma ray detection. We assembled a setup that employs plastic and NaI(Tl) scintillation detectors for beta-and gamma-ray detection, respectively. The obtained result shows that discrimination of Cs-134 and Cs-137 was successfully achieved. Radioactivity determined by measurement was in agreement with one prepared as a mixture. The results show that the method can be adapted to measure the radioactivity of samples contaminated by the accident at the Fukushima Daiichi Nuclear Power Plant