FIELD: physics.
SUBSTANCE: flow-type measurement cell of the apparatus is in the form of a truncated cone which is transparent or has transparent windows, in which is inserted and fixed at a given distance from the walls of the cell a solid or hollow transparent conical rod having dimensions such that the difference of the square of the inner radius of the cell and the square of the outer radius of the transparent rod, measured in one section of the cell, is constant for all sections of the cell. A light source has a light flux divider which enables to scan with a light beam sections of the cell on the entire length of the cell, and a photodetector is in the form of a series of separate photodetectors comprising at least two independent photodetectors.
EFFECT: high measurement accuracy.
2 cl, 2 dwg
