A study of sheath flow method in laser scattering particles size measurement

摘要

As an important and efficient method of particles size measurement, laser scattering has attracted great interest in the last decades. The sheath flow method has received extensive attention for its specific characteristic in cell detection and other fields. In this work, we report on a study of sheath flow method in laser scattering particles size measurement. In the particles size measurement system, an optical fiber laser was used as laser source, the light sensitive was confined to circular region with a diameter of less than 10μm by micro-lens focusing structure. Based on the scattering theoretical analysis of the particle size distribution from the scattering light energy, an improved sheath flow structure is proposed to obtain accurate and reliable scattering light signal from the particle passing through sheath flow pool. The digital voltage signals were measured via the amplification circuit and the data acquisition card. Numerical calculations and experiment results show that the sheath flow system is effective in the laser scattering particles size measurement.