Ultrafine grain measuring apparatus and method based on dynamic light scattering signal time coherence

Abstract

The invention relates to a device and a method for measuring ultrafine grains based on dynamic light scattering signal time coherence degree. An incidence light path consists of a laser, a convex lens and a sample cell; a receiving light path consists of a sample cell, a pinhole diaphragm and an optical filter; and an acquisition and processing unit for scattering signals consists of a photoelectric detector, a photon counting plate and a computer. The measuring method comprises the following steps: 1, using the laser as a light source to irradiate the sample cell filled with the grains; 2, using a photoelectric multiplier tube as the photoelectric detector to continuously measure scattered light signals generated by the grains at a scattering angle of 90 degrees; 3, using the photon counting plate to count impulse signals output by the photoelectric multiplier tube, wherein the time coherence degree of the signals is gradually reduced along with the improvement of a sampling cycle; and 4, calculating the grain sizes of the grains by the computer according to the change of the calculated signal time coherence degree. The device and the method have the advantages of low cost, simple steps, quick measuring speed, and simple device.

Description

technical field [0001] The invention relates to a device and method for measuring ultrafine particles based on the time coherence degree of dynamic light scattering signals. Background technique [0002] Particles refer to solids, liquids (oil droplets), gases (bubbles) or molecular clusters suspended in air or liquids. Usually, ultrafine particles refer to particles with a particle size below 10 microns. Ultrafine particles and their formations are ubiquitous in nature and production processes as raw materials, intermediates or products. They have a major impact on the performance and quality of products or materials, energy consumption, environmental quality, people's health, global weather and crop growth. Accurate measurement of ultrafine particle size has important economic and social significance. [0003] There are many methods for measuring particle size. As early as the 1980s, there were more than 400 kinds of particle measuring instruments. In terms of its measu...

AI Technical Summary

Problems solved by technology

They have their own characteristics, but limited by their working principles, except for electron microscopy and photon correlation spectroscopy in light scattering methods, the lower limit of measurement of other methods is difficult to enter the measurement range below 1 micron, even if submicron particles can be measured The measurement is far from its optimal or reasonable measurement range, and it is difficult to guarantee reliable measurement accuracy

Among them, the electron microscope has problems such as long measurement time, cumbersome sample preparation and high measurement requirements, so it is not suitable for online measurement

However, the particle measurement device of the photon correlation spectroscopy method needs to use an expensive mathematical correlator, so there is a disadvantage of high cost

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