Angular-Dependence Light Scattering—A High-Resolution Recording Instrument for the Angular Range 005–140°*

A unique optical instrument for the measurement of light scattering in physically nonhomogeneous systems is described. The scattering data provide a basis for the size characterization of optical inhomogeneities in the radius range 0.1 to 100 microns. The useful angular range of the instrument extends from about 0.05° to 140°. Angular resolution of 0.02° is readily attainable for characterizing large inhomogeneities at small angles. Scanning rates are 0.1, 0.4, 1.0, 4.0 and 20°/min. Light intensities varying by a factor of 108 are measured through the use of an optical attenuator which facilitates use of a 1P21 multiplier phototube at a low level of illumination. The phototube output is charted by a special high-impedance recorder having a full-scale sensitivity of 0.004 microampere. Angles are marked by an auxiliary pen on the recorder.