Conceptual design of thyroid dose monitoring system using -ray spectrometers

Nishino, Sho   ; Yoshitomi, Hiroshi   ; Tanimura, Yoshihiko   ; Takahashi, Masa 

In the situation of a severe nuclear accident, radioiodine monitoring in thyroid should be performed for a large number of people immediately after accident. We propose conceptual design of the portable thyroid dose monitoring system consisting of two -ray spectrometers and radiation shield, which is easily used at evacuation centers and incident command posts in the radiologically affected area. The experimental study of detectors and radiation shield were performed to confirm if the proposed monitor can satisfy the performance requirements. As a result, it was confirmed that the proposed monitor can assess thyroid equivalent dose less than 10 mSv by adopting CdZnTe or LaBr detectors with a tungsten heavy alloy shield, even in a high dose rate condition around several 10 Svh.