Experimental studies of the response of an optical counter to dry and liquid particles of different shape and refractive index

Abstract

The response of the Climet 208 optical particle counter in the 1 to 10 μm size range and over a range of shape and refractive index was experimentally measured by using four different metal halide salts. Dry spherical particles having smooth surfaces (latex spheres) and irregular surfaces (sodium fluoride and potassium chloride) fall on the same calibration curve even though their refractive indices cover the 1.34–1.59 range. Cubical dry NaCl particles show less response than the dry spherical particles, probably because of asymmetric light scattering. Metal halide salts all had a smaller response in the saturated aqueous state compared to the dry state.