Development of resonance ionization mass spectrometry of Sr isotopes, 2

Miyabe, Masabumi   ; Oba, Masaki ; Akaoka, Katsuaki ; Wakaida, Ikuo  ; Hasegawa, Shuichi*

Because of environmental pollution of the radioactive materials released from TEPCO's Fukushima Daiichi Nuclear Power Station, considerable attention has been focused on food safety in Japan. Whereas the principal pollutants for foods are radioactive Cs and Cs, the radioactive Sr, one of the alkaline earth elements like Ca and its radiation can damage bone marrow, is also one of the most important nuclide considering the possible occurrence of biological concentration through food chain. This Sr is the pure -ray emitter of which energy is 0.546 MeV (28.78 years) and is known as the nuclide for which analysis is difficult. For radiometric analysis, to eliminate various emitters which potentially interfere the Sr analysis, not only a repeated application of ion-exchange and coagulating sedimentation processes but also a period of longer than 2 weeks are needed to establish radioactive equilibrium between Sr and its daughter nuclide Y. To realize a prompt Sr analysis for marine foods, we are developing a new analytical technique by combining resonance ionization spectroscopy (RIS) and ion trap detection. In the present study, we have evaluated ionization efficiency and analytical performances using highly efficient and isotope-selective RIS scheme which we determined in our previous study.