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投稿者 抜粋 日時 2000 年 8 月 18 日 03:22:32:
回答先: やはり大本営発表だった。実は発表の２．５倍だった放射線 投稿者 ★阿修羅♪ 日時 2000 年 8 月 17 日 10:21:25:
ネイチャー 2000年 406巻 693頁 に掲載された論文(短信)の抜粋
Tokaimura accident: Neutron dose estimates from 5-yen coins
Masuchika Kohno* and Yoshinobu Koizumi+
* Department of Nuclear Engineering, Kyoto University, Yoshida, Sakyo, Kyoto 606-8501, Japan
+ Isotope Center, University of Tokyo, 2-11-16, Yayoi, Bunkyo, Tokyo 113-0032, Japan
After a criticality accident at a nuclear-fuel processing facility in Tokaimura, Japan, at 10:35 Japanese standard time on 30 September 1999, neutron emission continued until early the next morning. To estimate the neutron dose to the surrounding population, we collected 5-yen coins (37 weight per cent zinc) from places likely to have been exposed to radiation as a result of the accident and determined the amount of 65Zn generated in them in the nuclear reaction 64Zn + n --> 65Zn by spectrometrically measuring the photons emitted by 65Zn. Our results indicate that people evacuated to 350 m outside the irradiated area still received a significant neutron dose.
中略
Ambient dose equivalent values (in millisieverts at 1 cm depth) were calculated as about 220 mSv at 100 m, 6 mSv at 350 m and 1.8 mSv at 550 m. These estimates agree well with the early official estimates2, which were revised to about half some weeks later3. Our estimated exposures indicate that those living 350 m away from the accident - the distance to which people were advised to evacuate - were also irradiated by neutron doses of over 1 mSv.
後略
題名には必ず「阿修羅さんへ」と記述してください。