针对水下长期在线浊度探测需考虑器件不稳定以及出光窗口污染对探测精度的影响等问题,提出了一种使用双散射光功率比值表征浊度的探测方法.该方法使用一束平行光照射待测环境,并滑光路同时探测两点的90°散射光功率；然后,对获得的两个散射光功率值进行比值处理,以此得到待测环境的浊度.使用该方法设计了一种新的浊度探测结构,该结构满足严格的90°散射探测.理论推导和结构分析表明,该浊度探测器能有效降低光源漂移和窗口污染造成的扰动.实验结果显示,该方法表征的浊度系数与光衰减度线性良好,对于峰值变化30％的光源扰动,浊度系数最大变化仅为5％,显示该方法对光源漂移或出光窗口污染不敏感,适宜于水下在线探测浊度.%In consideration of the effects of the device instability induced by environmental fluctuation and the pollution of light-transmitting window on the on-line turbidity detection in line measurement, a new method to determine the turbidity in water is proposed based on the scattered-light power ratio measurement. This method uses two photodetectors to simultaneously detect the 90° scattered light power at different positions along the propagation path of a collimated light beam in the water environment. The turbidity of the water environment can be determined by calculating the logarithm of the scattered-light power ratio. The turbidity detector prepared based on this method detects 90° scattered light. The theoretical analysis indicates that this detector can in principle eliminate the influence of both the light source drifting and the window pollution on the measured turbidity. Experimental indi-ate the relationship between the two results measured with the turbidity detector and conventional transmission method. Furthermore, when the peak value of the light source fluctuates 30% ,the turbidity coefficient changes only 5% .which indicates the detector is insensitive to the light drifting and win-dow pollution. In conclusion, the detector is suitable for underwater detection of turbidity.
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