March 29, 2012 (JST)
Japan Aerospace Exploration Agency
Japan Atomic Energy Agency
Tokyo Electric Power Company

The Japan Aerospace Exploration Agency (JAXA) has constructed a prototype of a new device called the "Ultra-wide-angle Compton Camera," which can visualize radioactive substances that emit gamma rays. The camera was developed by applying technology for a gamma-ray observation sensor that will be installed in the next generation X-ray astronomy satellite "ASTRO-H."
This device combines the power of a wide-angle vision covering almost 180 degrees, and a nuclide whose unique feature is identification of gamma-rays, in order to visualize the distribution of Cesium 137 (Cs-137) and 134 (Cs-134) in any plot of ground or a house lot. Hence it can be utilized to obtain images of radioactive substances accumulated on rooftops and other raised locations that are difficult to survey using conventional investigation methods by human beings with a survey meter.

On February 11, JAXA, the Japan Atomic Energy Agency (JAEA) and Tokyo Electric Power Company (TEPCO) conducted a demonstration of dosimetry and imaging using the Ultra-wide-angle Compton Camera in Kusano district, Iidate Village, Fukushima Prefecture, an area which is designated as a planned evacuation zone. We were able to successfully capture high precision images of radioactive Cesium distribution with a much wider view as compared to that of a conventional gamma-ray camera.

JAXA and JAEA, in cooperation with TEPCO, will carry out further studies of possible practical uses of the Ultra-wide-angle Compton Camera for decontamination of radioactive substances and other related operations.

Attachment-1: Regarding the Ultra-wide Angle Compton Camera
Attachment-2: Report of the test result on the environmental radiation distribution measurement at Kusano area of Iitate village in Fukushima Prefecture
*The aforementioned attachments are only available in Japanese. We apologize for any inconvenience this may cause.