f Distribution of 137CS fallout in the environment deduced from gamma ray spectrometry

The nuclear reactor fire in Chernobyl on April 25, 1986 released clouds of radioisotopes which were swept northwards from the Ukraine over the Baltic Sea and across Sweden where they were deposited by rainshowers in the highlands of Norway. Most of these isotopes had a short half-life and are now present only in trace amounts. However one isotope, namely 137Cs has a half-life of approximately 30 years, so large areas of mid-Norway still exhibit anomalously high levels of radiation. Cesium tends to concentrate in the food-chain, typically in muscle tissue.