Toshiba Corp developed the "Portable Gamma Camera," which enables to easily find so-called "radiation hotspots."
The company will have a field test of the camera in collaboration with Fukushima City (Fukushima Prefecture, Japan) within December 2011 and begin to promote its use to the central bureaucracy and local governments in Japan in early 2012.
The Portable Gamma Camera combines gamma ray data measured by its radiation sensor and an image taken by its camcorder with a signal processing device. And it shows the amount of radiation in different colors. It uses red color for high amounts of radiation and yellow, green and blue colors for lower radiation levels.
The amount of radiation is not homogeneous in each area, and there are "hotspots," where radiation level is locally high. And it takes time to find hotspots by using radiation meters, Toshiba said.
The new machine shows radiation level with different colors on its screen as well as measures radiation level in a wide area in a short period of time, making it easier to find hotspots and improving the efficiency of decontamination work. Also, it is possible to confirm the decrease of radiation level by using the camera after decontamination work.
The Portable Gamma Camera was developed by improving the performance and reducing the size of Toshiba's gamma camera used for checking the insides of the buildings at the Fukushima Daiichi Nuclear Power Plant.
This time, the company improved sensitivity and measurement capability by about 30 times by using its own technologies to embed semiconductor detection elements and process signals and data. As a result, it became possible to detect a hotspot with a relatively low dose rate of 0.1μSv per hour (1mSv per year).
Furthermore, Toshiba reduced weight by about half by using smaller electronic circuits and redesigning the shield that is used to take images of radiation while blocking off radiation around the camera.
The camera measures 380 x 110 x 241mm and weighs 9.8kg. It is equipped with 128 semiconductor detection elements as radiation sensors. Its view angle is 60°. It can be powered by either an AC100V power source or batteries. When it is powered by batteries, it can be operated for three hours.