Speaker
Description
Some dusts including alpha-ray-emitting radio-active materials are called as "alpha-dust" and their sizes are expected to be less than 100 $\mu$m. These dust are assumed to be generated in the Fukushima Daiichi Nuclear Power Station, and their sizes, shapes and nuclear species should be determined to suppress the work list of the decommissioning. In this study, we have developed a prototype of a system aiming to observe the alpha-dust generated at the time of debris search in the Fukushima Daiichi Nuclear Power Station. Our system consists of scintillation materials, lens and CMOS camera; alpha-ray is first converted to visible light with the scintillator, and its image is obtained using a lens and an Si-semiconductor camera (CMOS camera) with a ultra-high position resolution. To obtain such high-resolution (less than 10 $\mu$m), we have developed novel scintillation materials with emission bands of 500 - 800 nm, and over 50,000 photons/MeV.Our system with the scintillation material can detect alpha-ray with a dwell time of 50 ms, and we show the alpha-ray imaging event with by event in this presentation.
