Improvement in Sideways Light Scattering Aerosol Particle Counter

Rearrangement of Optical Lens Geometry

Abstract

The characteristics of the sideways light scattering aerosol particle counter has been improved by rearrangement of the optical lens geometry to recieve more forward angle scattering light. Four counters with different optical lens geometry, employing respectively 60°, 70°, 80° and 90° mean scattering angle, have been constructed, and the calibration of these counters has been performed with uniform size polystyrene latex spheres.
The photo electrical pulses from a phototube are measured and counted automatically with the multichannel pulse height analysing technique, which is utilized widely in the field of nuclear science. The experimental values of counter responses are in good agreement with theoretical responses calculated by Mie theory of light scattering by transparent spherical particles.
As a result of theoretical and experimental studies on sideways counter, it has been found that the 60° counter has the most excellent characteristics among the test counters. The sensitivity of the 60° counter is three fold higher than that of the 90° counter, and there is little difference in the linearity of both counters.