Research institutions in Japan have started a joint program with the International Atomic Energy Agency to enhance the accuracy of radioactivity measurements to meet international standards, the University of Tsukuba said Feb. 3.
Research institutions in Japan have started a joint program with the International Atomic Energy Agency to enhance the accuracy of radioactivity measurements to meet international standards, the University of Tsukuba said Feb. 3.
The IAEA provides reference samples of soil and other materials that contain radioactive substances to 21 research facilities, including the Japan Atomic Energy Agency, the University of Tokyo and Osaka University. Deviations of their measurement devices will be calibrated by comparing their readings for the standard materials against the correct values.
"The program will not only help to ensure that results of measurements in Japan gain the trust of the international community," said Yuichi Onda, a professor of geomorphology at the University of Tsukuba who is involved in the project. "It will also help to respond to the general public's misgivings about the accuracy of measurement results."
In radiological measurements, the amounts of radioactive substances are estimated on the basis of gamma ray emissions, but measuring equipment can only monitor rays that travel in certain directions. Gamma rays are also partially absorbed by water, soil and other materials.
To ensure that measurements are precise, it is essential to evaluate beforehand what percentage of the gamma rays the measurement gauge can monitor. Any errors in that assumption lead to inaccurate estimates.
IAEA reference materials, which are employed as an international standard, have been limited until now in Japan, making it difficult to calibrate measurement instruments.
As part of assistance measures to help rebuild Fukushima Prefecture, the site of a major nuclear accident in March last year, the IAEA has distributed reference samples of soil, water, grass and other materials free of charge to the research facilities in Japan through the University of Tsukuba. Each participating facility will conduct measurements on those samples by mid-April and communicate their results to the IAEA.
The IAEA will thereupon notify them about the "correct" levels. IAEA officials will visit Japan in May and later to provide technical guidance.