Panoramic imaging of the distribution of radioactive substances in the environment
—Next-generation monitoring car "iRIS-V"—

Understanding the distribution of radioactive substances in the outdoor environment in Fukushima Prefecture is crucial for making smooth progress in decontamination work, and providing prompt information to residents. However, with techniques using conventional survey meters and similar tools, the incidence direction of radiation is cannot be measured. Therefore, it has been labor-intensive and time-consuming to survey over a wide area for locations with a high radiation dose rate (hot spots).

The Japan Atomic Energy Agency (JAEA) has developed the iRIS-V (integrated Radiation Imaging System-Vehicle), equipped with an omnidirectional 3D radiation imaging system. This system incorporates 144 gamma-ray imagers (Compton cameras) which measure and image the distribution of radioactive substances in a short period of time, in combination with 3D laser scanner.

The iRIS-V will make it possible to ascertain the distribution of radioactive substances in the environment quickly, and on the grounds of the Fukushima Daiichi Nuclear Power Station of Tokyo Electric Power Company Holdings.

The system can easily find radioactive hot spots in all directions, and this will help smooth decontamination and decommissioning. Unlike ordinal monitoring cars, our system visualizes the position and distribution of radioactive substances in addition to the air dose rate along the running route. Therefore there are high expectations for the system as a next-generation monitoring car.

A radiation image superimposed on a 3-D environmental model acquired by a 3D laser scanner.

The radiation source can be displayed three-dimensionally by superimposing the radiation image of the Compton camera on the 3-D environmental model acquired by a 3D laser scanner.
In the figure, the radiation source installed at the top of a car is visualized.