A simple shape-free model for pore-size estimation with positron annihilation lifetime spectroscopy

16th International Conference on Positron Annihilation

Wada, Ken^1 ; Hyodo, Toshio^1

Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan^1

关键词: Annihilation rates;    Classical model;    Combined model;    Effective size;    Free model;    Positron annihilation lifetime spectroscopy;    Size estimation;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/443/1/012003/pdf
DOI  :  10.1088/1742-6596/443/1/012003

来源: IOP

【 摘 要 】

Positron annihilation lifetime spectroscopy is one of the methods for estimating pore size in insulating materials. We present a shape-free model to be used conveniently for such analysis. 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 its Ps-lifetime to pore-size relation merges smoothly with that of the well-established Tao-Eldrup model (with modification involving the intrinsic Ps annihilation rate) applicable to very small pores. The combined model, i.e., modified Tao-Eldrup model for smaller pores and the modified classical model for larger pores, agrees surprisingly well with the quantum-mechanics based extended Tao-Eldrup model, which deals with Ps trapped in and thermally equilibrium with a rectangular pore.