Development of aerosol counter

Himeno, Yoshiaki; not registered; not registered; Iguchi, Tatsuro*

To develop in-situ aerosol particle counter, the method to utilize laser beam was selected, and its feasibility test has been carried out. The principle of the method is to measure the gravitational settling velocity of a particle and to calculate a particle size from the settling velocity by using Stokes equation. The particle being measured is sodium mist that is familiar to be handled by the present authors. The test is divided into two steps. In the first step, particle size distribution of mist was measured by a cascade impactor. The ABS code was modified for sodium mist, and numerical study was performed with this code to check reliability of the measured data. In the latter step, the laser counter was used to measure particle size distribution of mist. In this event, the particle size distribution previously obtained in the first step was used as reference data. The results of the present test revealed that the minimum particle size to be detected by the laser counter was about 1.0 m. To meet the requirement as the aerosol counter, particles as small as 0.5 m have to be detected. Hence, it was recognized that the data processing method of the present counter have to be modified.