Particle Size Fractionation of Airborne Gamma-Emitting Radionuclides by Graded Filters

Abstract

Three filters in series were employed to separate into groups, according to size, the nuclear debris suspended in air at ground level. The concentrations of airborne Ce(144)-Pr(144), Sb(125), Cs(137), Zr(95)-Nb(95), Mn(54), and Ru(106)-Rh(106) in each size group were determined by gamma spectral analysis. Particles having diameters of less than 1.75 microns contained a minimum of 88 percent of the total activity.