Dynamic calibration of an aerosol monitor with natural and artificial alpha-emitters

Measurement of airborne artificial /spl alpha/-activity concentrations in the presence of naturally occurring radionuclides requires reliable subtraction of the natural contribution and precise calibration. Therefore, the commercially available aerosol monitor LB150D-R was calibrated dynamically at the IPSN/CEA in Saclay, France. Aerosols with activity median aerodynamic diameters of 0.4 /spl mu/m and 4 /spl mu/m labelled with /sup 239/Pu were generated and isokinetically sampled by the aerosol monitor. The response to /sup 239/Pu activity concentrations and detection limits in the presence of radon progeny were determined. The retention of aerosols and their distribution on the filter was investigated using fluoresceine labelled aerosols.