الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
In this study, a 9-stage high volume low pressure cascade
actor operates at flow rate of 4 m3/h has been designed and ,llt according to the theory discussed herein. The impactor .eary is satisfactory only if the impactor desigen and operation tisfay the assumption of the theory. The stage operating ’essures of the new impactor were calculated using isentropic ow relationships. Interpretation of impactor data are based on .e assumption that the class limits can be edequately defind by ’ut-off” aerodynamic diameters, i. e., the diameter at which the llection efficiency of successive stage is 50%. The stage .ut-off” diameters were calculated frmn the Stokes equation. The lculated aerodynamic ”cut-off” diameters of stages 1-9 (stages ’e numbered starting from the smallest ”cut-off” diameter) were
An impactor should be experimentally calibrated with the ame type of collection surface and at the same value of flow rate s those to be used in its intended application for providing ~liable particle size data. The calibration should be done by Eeping flow rate constant and varying particle sizes. Wall losses ~uld be determined even through they are ignored in the llculat ions of collect ion eff iciencies, The lower stage fficiencies of the new and Berner impactor were cal i brated with
odisperse laboratory aerosols, which required development work ’the submicron aerosols.
In this study, Measurements have been performed with Berner lscade impactor in the open air for determining the activity size stribution of the radionuclides 2s4Pb, 2s2Pb, 7Be and 2soPb.