A simple shape-free model for pore-size estimation with positron annihilation lifetime spectroscopy
A simple shape-free model for pore-size estimation with positron annihilation lifetime spectroscopy
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DOI：
10.1088/1742-6596/443/1/012003
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发表时间：
2013-06
期刊：
影响因子：
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通讯作者：
K. Wada;T. Hyodo
中科院分区：
文献类型：
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作者：
K. Wada;T. Hyodo
正电子湮没寿命谱是估算绝缘材料孔径的方法之一。为了便于这种分析，我们提出了一种无形状模型。通过引入与正电子素(Ps)的有效尺寸相对应的参数，对经典图像中的基本模型进行了修正。这个参数被调整，使得它的Ps寿命与孔径大小的关系与适用于非常小的孔的已建立的Tao-Eldrup模型(经过修改，涉及本征Ps湮没速率)顺利地融合在一起。组合模型，即修正的小孔道模型和修正的大孔道经典模型，与基于量子力学的扩展的Tao-Eldrup模型符合得出奇地好，后者处理捕获在矩形孔洞中的Ps和热平衡。
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.