透射电子显微镜中用于测量样品厚度的电子能量损失谱对数比技术。
EELS log-ratio technique for specimen-thickness measurement in the TEM.
作者信息
Malis T, Cheng S C, Egerton R F
机构信息
Physical Metallurgy Research Labs, Ottawa, Ontario, Canada.
出版信息
J Electron Microsc Tech. 1988 Feb;8(2):193-200. doi: 10.1002/jemt.1060080206.
We discuss measurement of the local thickness t of a transmission microscope specimen from the log-ratio formula t = lambda ln (It/I0) where It and I0 are the total and zero-loss areas under the electron-energy loss spectrum. We have measured the total inelastic mean free path lambda in 11 materials of varying atomic number Z and have parameterized the results in the form lambda = 106F (E0/Em)/ln (2 beta E0/Em) where F = (1 + E0/1,022)/(1 + E0/511)2, the incident energy E0 is in keV, the spectrum collection semiangle beta is in mrad, and Em = 7.6Z0.36. This formulation should allow absolute thickness to be determined to an accuracy of +/- 20% in most inorganic specimens.
我们讨论了通过对数比公式(t = \lambda \ln (I_t/I_0))来测量透射显微镜样品的局部厚度(t)，其中(I_t)和(I_0)分别是电子能量损失谱下的总损失面积和零损失面积。我们测量了11种不同原子序数(Z)的材料中的总非弹性平均自由程(\lambda)，并将结果参数化为(\lambda = 106F (E_0/E_m)/\ln (2\beta E_0/E_m))，其中(F = (1 + E_0/1,022)/(1 + E_0/511)^2)，入射能量(E_0)以keV为单位，谱采集半角(\beta)以mrad为单位，且(E_m = 7.6Z^{0.36})。这种公式化方法应能使大多数无机样品的绝对厚度测定精度达到(\pm 20%)。
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