Development of omni-directional directional detectors (FRIE), 1; Detector design and its characteristics

Torii, Tatsuo*  ; Sugita, Takeshi*; Sasaki, Miyuki  ; Sanada, Yukihisa   

Using a prototype FRIE detector system constructed with 16 tetrahedral GAGG detectors with 12 mm on each side, we obtained measured data of radiation distribution around a hot spot in an environment with a surface dose rate of 10 micro Sv/h or higher. Two conditions were applied for the evaluation of image reconstruction: a fixed measurement condition at about 1 m from the hot spot and a rotational measurement condition at about 1 m from the hot spot, and the accuracy of the radiation images was compared. In this presentation, as the first of the series of presentations, we report the results obtained from the field measurements in the environment around the TEPCO's Fukushima Daiichi Nuclear Power Station by the prototype FRIE detector system.