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

Science  15 Jan 1965:
Vol. 147, Issue 3655, pp. 290-292
DOI: 10.1126/science.147.3655.290


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 Ce144-Pr144, Sb125, Cs137, Zr95-Nb95, Mn54, and Ru106-Rh106 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.