Foundation of pore size estimation with positronium lifetime and its application

点击翻译按钮获取中文摘要

A shape-free model to be used for the estimation of the pore size has been developed. A basic model in classical picture is modified by introducing a parameter corresponding to an effective size of the positronium (Ps). This parameter is adjusted so that the model merges smoothly with the well-established modified Tao-Eldrup model.The present model has been applied to silica aerogel, which consists of a three dimensional random network of silica (SiO2) nano-particles. A well-known unresolved issue with this material is that the pore size estimated with standard methods gives macroscopic density inconsistent with that directly measured. In contrast, the quantity estimated with the present model agrees very well with that directly measured. This verifies that the present method gives reliable value for the size of large and complex vacant volume for which the other methods cannot give reliable estimation.