TEPCO's Space-Age Decon Tool Can Visualize Nuclide, Direction and Intensity of Radiation

Finally there's something sort of "high-tech" about the whole "decontamination" business which has boasted screw drivers, brooms and blue tarp as effective decon tools outside Fukushima I Nuke Plant, and vacuuming and strip-painting inside the plant compound. One of the "high-tech" items is GPS used to map the contaminated areas (see my previous post), and the other is a Compton camera developed by Japan's space agency.

TEPCO has been doing the GPS survey assisting the government research institutions OUTSIDE the plant to identify the radiation contamination. Examples of the survey were announced at the press conference on June 15, 2012.

Browsing through the press handout on June 15 titled "Developing Technology on Monitoring Radioactive Materials and Decontamination", I found a very interesting picture taken by a "super-wide angle Compton Camera" developed by JAXA (Japan Aerospace Exploration Agency).

According to TEPCO's explanation (page 5 of the handout),

The utilization of the Compton camera experimentally produced by JAXA for decontamination is currently under consideration (JAEA and TEPCO). A “super-wide angle Compton camera” allows to visualize radioactive materials such as cesium-134 and cesium-137 by identifying the nuclide, direction and intensity of radioactive materials excluding the air dose rate of the environment (See below).

It is a bit unnerving to "see" the radiation.

From JAXA's English website, the press release on March 29, 2012:

Visualization of Radioactive Substances
with JAXA's 'Ultra-wide-angle Compton Camera'

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. 

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Reference link: http://www.astro.isas.jaxa.jp/~takahasi/index-e.html

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