气体密度对瑞利散射法测量团簇尺寸影响的初步分析

 瑞利散射法被广泛地应用于测量团簇尺寸，通常视散射信号的强弱只正比于团簇的大小。从理论推导得到瑞利散射信号并不仅仅是团簇尺寸的函数，而与团簇尺寸、气体密度和结合率均有关系，认为采用瑞利散射法测量团簇尺寸应考虑气体密度对测量结果的影响。并用该分析方法研究了氩团簇沿喷嘴轴线的尺寸分布情况：团簇尺寸沿喷嘴轴线并不是单纯的单调变化，而是在某个位置达到最大值，并且这个位置与背景压强等因素有关。

Influence of gas density on measuring clusters size by Rayleigh scattering method

The Rayleigh scattering method is widely adopted in measuring cluster size. In general, it is considered that the intensity of scattering corresponds to the cluster size directly. However, this paper deduces that the intensity is not only related to cluster size, but also to gas density and binding probability. It suggests that gas density should be taken into account in analyzing the measurement results of Rayleigh scattering method. Furthermore, the method is applied in measuring the size distribution of argon cluster along the axis of nozzle. It is found that the cluster size doesn’t vary linearly along the nozzle axis, whereas it reaches maximum at a certain position which depends on some parameters including the background pressure．