Patent ID: 7982874

Claim:
A method of measuring sizes of particles in a liquid, comprising: illuminating a scattering volume with an illuminating multimode optical fiber; collecting the multiple and single scattered light by a primary collecting multimode optical fiber and one or more auxiliary collecting multimode optical fibers, all of the illuminating, primary collecting and auxiliary collecting multimode optical fibers being arranged parallel to each other; detecting the multiple and single scattered light by a light detector; providing spatial coherence condition for the multiple and single scattered light at output ends of the primary collecting multimode optical fiber and the one or more auxiliary collecting multimode fibers in front of the light detector; and determining particle sizes using optical mixing spectroscopy of scattered light, where particle size r is determined from relationship: r = ( r aux r pr 2 ⁢ A + B r pr ) - 1 where r pr , r aux are particle radii obtained as assumed for single scattering by the primary and auxiliary collecting multimode optical fibers, respectively; A and B are values of universal dependence of normalized particle radius r pr /r on r auw /r pr ratio.