[1D11-17] Nuclide analysis, Radioactivity measurement

[1D12] Rapid detection method of radioactive particles in the atmosphere

Results of field tests in “Difficult-to-return zone” and design improvement

*Tatsuyuki Maekawa¹, Yuji Oshima¹ (1. Toshiba Power Systems Radiation Techno-Service Co., Ltd.)

Keywords:Radioactive concentration in the atmosphere, Rapid detection, Monitoring, Gamma-ray, Spectrometer, Difficult-to-return zone, temporary access

We have propsed the rapid detection method of radioactive particles in the atmosphere¹⁾. It consists of a conventional gamma-spectrometer with the novel shaped shield with two-pi aperture to zenith direction. To apply this method to Cesium airborne monitoring in “Difficult –to-return zone” of Fukushima, measurements, evaluation and design improvements were carried out. As the result, we confirmed that the state of 30Bq/m³ can be detected with 11min. measurement, and concluded that this method is a promising way of rapid airborne monitoring system in “difficult-to-return zone” of Fukushima.