AN AUTOMATED LIGHT-SCATTERING SYSTEM SCANNING IN 2 SPHERICAL ANGLES

We have designed and built a light scattering system that can detect scattered light in two spherical angles with scanning ranges more than 270° about the vertical axis and 100° about a horizontal axis. The detector and the sample holder are automated by high-precision stepping motors with a minimal angular increment 0.01° or 0.02°. A novel modular design in the detector allows the experimenter to examine the image of the scattering object and the direction of the scattered light while the detector is fixed at the measurement position. The angular resolution of the system is smaller than 0.19° in both azimuthal and polar directions. This setup has been successfully applied to study the static and dynamic properties of the ordered phases in colloidal solutions.