Radioactivity in the highly contaminated area near the Chernobyl site

Field measurements of radioactivity were performed in highly contaminated areas around Chernobyl in the summer of 1990. Six radionuclides including the most dominant¹³⁷Cs have been identified in soil samples through -ray spectrometry. The relation between the -ray dose rate above the ground and the radioactivity density in soils has been investigated. The external dose from deposited radiocesium for the period of 70 years after the deposition has been evaluated to be about 5 mSv per 1 and 0.5 Ci km^–2 of¹³⁷Cs and¹³⁴Cs deposition, respectively.