Method and device for measuring particles by polarized light scattering

Abstract

The invention discloses a method and device for measuring particles by polarized light scattering. In a measurement process, an air sample to be detected flows through a testing region at a constant flow speed and laser is irradiated to the testing region after being subjected to focusing and polarization. The method comprises the following steps: (1) detecting Strokes vectors of scattered light of current particles after laser scattering, wherein the Strokes vectors represent the light intensity and a polarization state of the scattered light; (2) respectively calculating according to the Strokes vectors to obtain polarization parameters of the scattered light; (3) comparing the polarization parameters of the scattered light with standard polarization parameters of the scattered light in a standard library, and finding a particle diameter region and a refractive index which correspond to the proximate group of standard polarization parameters; and (4) determining the corresponding components of the current particles according to the refractive index so as to obtain component information and particle diameter range information thereof. The method and the device disclosed by the invention can be used for analyzing to obtain the component information of the particles; the particle diameter distribution of the small-diameter particles can be accurately distinguished accurately when being analyzed; meanwhile, the cost can be controlled well.

Description

【Technical field】 [0001] The invention relates to the detection of particulates in the air, in particular to a method and device for measuring particulates by polarized light scattering. 【Background technique】 [0002] The particle size distribution and concentration detection of particulate matter is an important research object and part of atmospheric environment detection, and there are many methods for the study of particle size distribution, concentration and composition of particulate matter. The main methods are oscillating balance method, filter membrane weighing method, piezoelectric crystal method, beta ray absorption method, light transmission method and light scattering method. In the actual measurement, because of the reusability and accuracy of the instrument, the vibration balance method and the light scattering method are mainly used to measure the particle concentration. Although the former has high precision, it is too expensive for general experimental res...

AI Technical Summary

Problems solved by technology

In the actual measurement, because of the reusability and accuracy of the instrument, the vibration balance method and the light scattering method are mainly used to measure the particle concentration. Although the former has high precision, it is too expensive for general experimental research and personal use, and In recent years, with the development of optoelectronic devices such as photodetectors and signal amplifiers, the light scattering method has increasingly become the preferred method for more and more people.

However, the existing methods for analyzing particulate matter based on the principle of light scattering are mostly used to analyze the particle size distribution of particulate matter and calculate the concentration of particulate matter, but cannot distinguish the specific components of particulate matter

Moreover, when the existing analysis method analyzes the particle size distribution, it can only distinguish the particle size distribution of large particle size particles, and cannot accurately distinguish the particle size distribution of small particle size particles.

This is because, in the existing analysis and measurement methods, the measurement and analysis are performed based on the scattered light intensity. However, since the scattered light intensity is proportional to the particle size, the scattered light intensity of the particles with a small particle size is very weak and will be absorbed by the large particle size. Due to the coverage of scattered light, the information of small particle size particles is missing during the analysis of scattered light intensity, so the detection of small particle size particles is inaccurate, and the particle size distribution of small particle size particles cannot be distinguished often.

While increasing the number of detectors at multiple scattering angles or improving detector sensitivity is the solution, this presents challenges in terms of cost and structural complexity

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