Department of Physics, Stockholm University, SE-106 91 Stockholm, Sweden.
Ultramicroscopy. 2011 Jan;111(2):79-89. doi: 10.1016/j.ultramic.2010.10.006. Epub 2010 Oct 26.
Gold's iterative deconvolution algorithm has been applied to one-dimensional EEL spectra from hexagonal BN. The experimental resolution was varied from 1.1 to 2.25 eV and Gold's algorithm was able to restore low-loss and core-loss spectra overall well. To estimate the instrument response function, the most convenient method was to extract the zero-loss peak from the low-loss spectrum. By instead using low-loss spectra as kernel, as suggested by Egerton, enhanced energy resolution could also be obtained with plural scattering simultaneously removed. It is further shown how the FWHM of the π* peak in the boron K-edge of hexagonal BN is reduced from 1.4 to 0.7 eV with almost no noise amplification after 500 iterations while resolving the σ* doublet. The result was almost identical after a stunning 5000-10,000 iterations, implying that Gold's method converges and can be stable for a large number of iterations. However, for lower-intensity spectra the number of iterations is limited. The results close to the intense zero-loss peak were uncertain and further testing with better experimental resolution is recommended. It is also found that to improve the resolution and not just sharpen the spectra, a large number of iterations is required.
戈尔德迭代反卷积算法已应用于六方 BN 的一维 EEL 光谱。实验分辨率从 1.1 到 2.25 eV 不等，戈尔德算法总体上能够很好地恢复低损耗和核心损耗光谱。为了估计仪器响应函数，最方便的方法是从低损耗光谱中提取零损耗峰。相反，正如 Egerton 所建议的，通过使用低损耗光谱作为核函数，也可以在同时去除多重散射的情况下提高能量分辨率。进一步表明，在经过 500 次迭代后，六方 BN 的硼 K 边的 π峰的半峰全宽从 1.4 降低到 0.7 eV，同时分辨率 σ双峰，几乎没有噪声放大。在令人惊叹的 5000-10000 次迭代后，结果几乎相同，这意味着戈尔德的方法可以收敛，并且可以在大量迭代中保持稳定。然而，对于强度较低的光谱，迭代次数是有限的。靠近强零损耗峰的结果是不确定的，建议进一步用更好的实验分辨率进行测试。还发现，为了提高分辨率而不仅仅是锐化光谱，需要进行大量的迭代。
