Development of a large-area alpha imaging detector capable of measuring the detailed distribution of alpha contaminations on hands and feet

Morishita, Yuki   ; Higuchi, Mikio*; Kaneko, Junichi* ; Kitagawa, Yuichi*; Akedo, Jun*; Soma, Mitsugu*; Matsui, Hiroaki*

This paper describes the development of a large-area imaging detector capable of measuring the detailed distribution of alpha particles on hands and feet for use in entry/exit control monitors in decommissioning sites such as the Fukushima Daiichi Nuclear Power Plant. The detector was developed using a commercially available ZnS(Ag) scintillator and an electron multiplying CCD camera. The effectiveness of the detector was evaluated by measuring several types of radiation sources, and the results showed that it was possible to detect the position of alpha particles in a very short time, and contamination levels of up to 11 Bq/cm could be visualized. The field of view of the detector was also checked, and it was confirmed that the setup had a field of view that could cover most of the hand and the sole of the shoe. This detector is expected to be useful for preventing internal uptake and decontamination.