Visualization of radioactive substances with a Si/CdTe Compton Camera

Dust containing radioactive materials dispersed following the Fukushima nuclear power plant accident in March 2011. Gamma-rays are emitted in the process when unstable nuclei in the materials decay. Based on the technology of Si/CdTe Compton Camera, we have manufactured a quick prototype model for the use in the field. The camera, now called a "Ultra-Wide-Angle Compton Camera" was successfully applied to visualize the distribution of radio-active substances in the Fukushima area.