The system for determining parameters of a particle described in this document is a government-owned invention that is available for licensing. The background of the invention is outlined, and drawings of the system together with a detailed description of its function are provided. A collector contains a hole and annular apertures for transmitting a pair of conical, coaxial sheets of radiant energy. A beam of energy is directed through the hole, whereby a scattering volume is defined by the beam diameter and the fields of view of the apertures. When a particle moves through the volume, energy is scattered through the apertures and is detected to generate a pair of signals, each having a magnitude dependent upon the intensity of the energy in one of the conical sheets. A device responds to the magnitudes of the signals to indicate the size or nonspherical characteristics of the particle. (Author/JR)