Preliminary study on determination of surface contamination density on soil in heavily contaminated areas using a CeBr scintillation detector coupled with lead shielding

Kowatari, Munehiko; Tanimura, Yoshihiko   

Authors attempted to apply a CeBr scintillation detector coupled with an appropriate lead shield to in-situ environmental radioactivity measurement for evaluation of surface contamination density on soil in heavily contaminated areas. Contamination by a vast amount of radioactive materials released due to the nuclear accident at the Fukushima Daiichi Nuclear Power Plant still remains. Both decontamination and remediation works have been recognized a challenging practice. Particularly, methodologies for confirmation of decontamination effect in heavily contaminated areas have been being intensively developed. This study preliminary investigates an adaptability of a shielded CeBr scintillation detector for environmental radioactivity measurement. An appropriate shielding to spectrometer would allow to limit the area to be monitored and consequently lead to expand the upper detection limit of surface contamination density on soil. In this study, determination of surface contamination density for Cs and Cs was focused. Suitable design of shielded CeBr detector was investigated so that in-situ environmental radioactivity measurement could be performed even in higher dose rate areas.