Environmental Radiation: Measurements of Dose Rates

Abstract
The exposure dose from environmental sources of radiation was determined by means of an ionization chamber, by gamma-ray spectrometry in the field, and by measurements of radioactivity in soil cores. The exposure dose from cosmic radiation was found to be 4.4 ± 0.2 µr/hr, that from natural radioactivity 8.0 ± 0.3 µr/hr, and the contribution from fission products varied from 2.0 to 7.5 µr/hr during the interval in question.