Monte Carlo modeling of cavity imaging in pure iron using back-scatter electron scanning microscopy

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• 作者：Qiang Yan^a ; Jonathan Gigax^b ; Di Chen^b ; F.A. Garner^b ; ^c ; Lin Shao^b ; ^{lshao@tamu.edu" class="auth_mail" title="E-mail the corresponding author}
• 刊名：Journal of Nuclear Materials
• 出版年：2016
• 出版时间：November 2016
• 年：2016
• 卷：480
• 期：Complete
• 页码：420-428
• 全文大小：2260 K

文摘

Backscattered electrons (BSE) in a scanning electron microscope (SEM) can produce images of subsurface cavity distributions as a nondestructive characterization technique. Monte Carlo simulations were performed to understand the mechanism of void imaging and to identify key parameters in optimizing void resolution. The modeling explores an iron target of different thicknesses, electron beams of different energies, beam sizes, and scan pitch, evaluated for voids of different sizes and depths below the surface. The results show that the void image contrast is primarily caused by discontinuity of energy spectra of backscattered electrons, due to increased outward path lengths for those electrons which penetrate voids and are backscattered at deeper depths. Size resolution of voids at specific depths, and maximum detection depth of specific voids sizes are derived as a function of electron beam energy. The results are important for image optimization and data extraction.