多角度动态光散射角度误差对权重估计的影响

角度权重估计是多角度动态光散射测量技术的重要环节，其方法可依赖于光强均值或光强自相关函数基线。角度误差对颗粒粒度分布测量准确性的影响在很大程度上取决于角度权重系数的估计。通过对模拟和实测动态光散射数据的反演，研究了角度误差对基线值法和光强均值法进行权重估计对粒度分布反演的影响。结果表明:采用两种方法进行角度加权，无角度误差时反演结果无显著差异。存在角度误差时，误差对光强均值法反演结果的影响大于基线值法，并且对大颗粒的影响显著大于对小颗粒的影响。导致这一结果的原因在于，当散射角存在误差时，基于Mie理论的光强均值法得到的权重系数为理论值，与实测的光强自相关数据所对应的权重系数存在偏差。而且随着颗粒粒径的增大，Mie散射光强随散射角变化呈现出更为剧烈的波动，致使这种偏差加大。因此，采用基于Mie散射理论的光强均值法进行角度加权，对多角度光散射测量装置应提出较高的精度要求。

Effect of angular error on weighting coefficient in multiangle dynamic light scattering

Angular weight estimation is an important part of multi-angle dynamic light scattering technique. Its methods include autocorrelation function baseline method and light intensity average method. The effect of angular error on the measurement accuracy of particle size distribution, in the multi-angle dynamic light scattering, largely depends on the estimation of the angular weight coefficient. Based on the inversion of simulated and measured dynamic light scattering data, the effect of angle error on the inversion of particle size distribution by the weight estimation of autocorrelation function baseline method and light intensity average method was studied. The results show that there is no significant difference between the two methods without angle error. However, when the angle error exists, the influence of error on the inversion result of light intensity average method is greater than that of autocorrelation function baseline method, and the influence on large particles is greater than that on small particles. The reason for this result is that the weight coefficient obtained by light intensity average method based on Mie theory is the theoretical value, and there is a deviation between the theoretical value and the weight coefficient corresponding to the measured light intensity autocorrelation data. Moreover, with the increase of particle size, Mie scattering intensity exhibits a more drastic fluctuation with the scattering angle change, which causes the deviation to increase. Therefore, the angle weighted method based on Mie scattering intensity value was applied, and the precision of the multi-angle light scattering measurement device should be higher.