Autoradiographic investigation of radionuclide alpha-activity in soil and plant samples from Chernobyl zone

Alpha-active ''hot particles'' in soil and plant samples collected in the Chernobyl zone have been investigated by an auto-radiographic method. The size and activity of the ''hot particles'' were measured enabling their contribution to the radiation dose to be calculated. A correlation between the measured particle parameters was established. The method used for the particle size measurement with the help of a low sensitivity BYa-2 type photoemulsion is described. The measured mean diameter of the hot particles varies from 10 to 200 μm and their activity from 10-1 to 10-5 Bq. The most active particles (10-1 - 10-2Bq) were found only in soil. Leaf samples after the same exposure contained particles with activity not higher than 10-3 Bq. (author)