Optimal design of a wide dynamic range turbidity measurement system based on single photon technology

Abstract

A wide range turbidity measurement system based on the light scattering method and light transmission method was developed to measure the turbidity of liquids. In order to solve the problem of accuracy attenuation of the light scattering method in the case of measuring high turbidity and the light transmission method in the case of measuring low turbidity, and meet the requirements of large-scale measurement in one system, it is proposed to use the light scattering method to measure low turbidity and the Beer-Lambert law of light transmission method to measure high turbidity methods. Use an avalanche photodiode (APD) to detect the intensity of scattered light or transmitted light, and convert the intensity of light into the number of photons based on single-photon counting technology. In order to obtain a reasonable measurement range of the light scattering method and the light transmission method in this system, a series of experiments were carried out. Under a specific incident light intensity, the experimental results show that the reasonable detection range of the light scattering method is 1 NTU-324 NTU, within this range, the system exhibits good stability. The reasonable detection range of the light transmission method is 325NTU-815NTU, within this range, the system still shows good stability. The widerange turbidity measurement system in this article has broad applicability and can be used to monitor urban drinking water, factory sewage discharge, and other industries.