Development of a Si-PM based alpha camera for plutonium detection in nuclear fuel facilities

Morishita, Yuki   ; Yamamoto, Seiichi*; Izaki, Kenji ; Kaneko, Junichi* ; Toi, Kohei*; Tsubota, Yoichi*

Alpha particles are monitored for detecting nuclear fuel material (i.e., plutonium and uranium) at nuclear fuel facilities. In this study, we developed a new alpha-particle imaging system by combining an Si-PM array, which is insensitive to noise, with a Ce-doped GdAlGaO (GAGG) scintillator, and evaluated our developed system's fundamental performance. The scintillator was 0.1-mm thick, and the light guide was 3.0 mm thick. An Am source was used for all the measurements. We evaluated the spatial resolution by taking an image of a resolution chart. A 1.6 lp/mm slit was clearly resolved, and the spatial resolution was estimated to be less than 0.6-mm FWHM. The energy resolution was 13% FWHM. A slight distortion was observed in the image, and the uniformity near its center was within 24%. We conclude that our developed alpha-particle imaging system is promising for plutonium detection at nuclear fuel facilities.