Igushi Tatsuo, Yoshida Hideto
Horiba, Co., Ltd., Miyanohigashi, Kisshoin, Minami-ku, Kyoto, Japan.
Rev Sci Instrum. 2011 Jan;82(1):015111. doi: 10.1063/1.3520136.
We first applied the Twomey iteration method to the low-angle laser light scattering (LALLS) method. The Twomey method is known by the simple iteration algorithm for Fredholm integral equation. However, the algorithm is not applied to the LALLS result itself because the kernel function pattern is not stable. We solved the unstable kernel issue by modifying the Twomey algorithm to fit the LALLS data in this study. The performance of inversion was studied by computer simulation and experimental results from detectors containing 24 elements from angle 0.0005 to 2.5 rad. The computer simulation was carried out for particles of mean sizes from 0.1 to 1000 μm with mono-dispersion and log-normal distributions. A conventional algorithm is also carried out to compare the performance of the Twomey method. The noise effect of the inverse problem was tested by computer simulation. Experimental results were measured with standard polystyrene latex from 0.081 to 1007 μm. All the tests were performed under conditions in which the light from a linearly polarized laser at 633 nm was scattered by a diluted aqueous suspension. The modified Twomey (MT) method and conventional method show good reproduction results for particles with log-normal distributions. However, narrow distribution particles indicate that the MT method shows excellent reproduction results when compared with the conventional method.
我们首先将Twomey迭代方法应用于低角度激光光散射（LALLS）方法。Twomey方法以Fredholm积分方程的简单迭代算法而闻名。然而，由于核函数模式不稳定，该算法未应用于LALLS结果本身。在本研究中，我们通过修改Twomey算法以使其适用于LALLS数据来解决核不稳定问题。通过计算机模拟以及来自包含24个元素、角度范围从0.0005到2.5弧度的探测器的实验结果，研究了反演性能。针对平均尺寸从0.1到1000μm的单分散和对数正态分布的颗粒进行了计算机模拟。还执行了一种传统算法以比较Twomey方法的性能。通过计算机模拟测试了反问题的噪声效应。使用0.081至1007μm的标准聚苯乙烯胶乳测量了实验结果。所有测试均在633nm线偏振激光的光被稀释水悬浮液散射的条件下进行。改进的Twomey（MT）方法和传统方法对具有对数正态分布的颗粒显示出良好的再现结果。然而，对于窄分布颗粒，与传统方法相比，MT方法显示出优异的再现结果。
