Image dissector for size and position of statically suspended particles

Abstract

The use of an image dissector to size and determine the coordinates of suspended particles is described. The device uses a laser light source and 90 degrees scattering. Volume scanning is accomplished using the internal x-y dissector scan and a mechanically stepped movement in z. Current application is toward the Atmospheric Cloud Physics Laboratory under development by NASA for a series of Space Shuttle experiments.

Development of nonimaging optics for particle counters

“…To obtain a larger measurement plane, the focal depth around the focal point is used as the measurement plane. 2 We assume that we have a homogeneously illuminated plane through which equally sized particles are transported at different positions and that they scatter light with the same intensity ͑ideal scatterer in all directions͒. When a particle is located at the focal point, the scattered light is optimally focused onto the detector and the detected light intensity is maximal.…”

A New Particle Counter Using Nonimaging Optics and Real-Time Correlation Filter for Particle Detection

“…This phenomenon is called local dependence of scattered light. In practical application, the focal depth around the focal point is designed as a sensing zone, but it causes strong local dependence (Knollenberg 1979). The longer the focal depth, the stronger the local dependence is in the sensing zone.…”