Radon flux at the Earth-air interface

Abstract

A radon condenser utilizing a trap cooled by liquid oxygen has been used to measure the radon content of the atmosphere and of the soil gases escaping through the surface of the earth. The average atmospheric-radon concentration at ground level in the Socorro area was found to be 0.24×10−12 curie/liter, and a measurement of the radon flux at the earth-air interface gave a result of 90×10−18 curie/cm2 sec. The radon content of the air showed a diurnal fluctuation, whereas the radon flux at the earth-air interface appeared to be relatively constant over a diurnal period. Diffusion theory is used to derive an expression for the radon flux in terms of the concentration of radon in the soil at depth. The flux value measured is consistent with a concentration of radon produced by 1.1×10−12 gram of radium per gram of soil.