Quantitative Modeling of High-Energy Electron Scattering in Thick Samples Using Monte Carlo Techniques

Journal Article · 08 January 2025 · Applied Sciences

DOI: https://doi.org/10.3390/app15020565 · OSTI ID:2507149

Quintard, Bradyn  ^[1]; Yang, Xi  ^[2]; Wang, Liguo ^[3]

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1. Dartmouth College, Hanover, NH (United States)
2. Brookhaven National Laboratory (BNL), Upton, NY (United States). National Synchrotron Light Source II (NSLS-II)
3. Brookhaven National Laboratory (BNL), Upton, NY (United States)

Cryo-electron microscopy (cryo-EM) is a powerful tool for imaging biological samples but is typically limited by sample thickness, which is restricted to a few hundred nanometers depending on the electron energy. However, there is a growing need for imaging techniques capable of studying biological samples up to 10 µm in thickness while maintaining nanoscale resolution. This need motivates the use of mega-electron-volt scanning transmission electron microscopy (MeV-STEM), which leverages the high penetration power of MeV electrons to generate high-resolution images of thicker samples. In this study, we employ Monte Carlo simulations to model electron–sample interactions and explore the signal decay of imaging electrons through thick specimens. By incorporating material properties, interaction cross-sections for energy loss, and experimental parameters, we investigate the relationship between the incident and transmitted beam intensities. Key factors such as detector collection angle, convergence semi-angle, and the material properties of samples were analyzed. Our results demonstrate that the relationship between incident and transmitted beam intensities follows the Beer–Lambert law over thicknesses ranging from a few microns to several tens of microns, depending on material composition, electron energy, and collection angles. The linear depth of silicon dioxide reaches 3.9 µm at 3 MeV, about 6 times higher than that at 300 keV. Meanwhile, the linear depth of amorphous ice reaches 17.9 µm at 3 MeV, approximately 11.5 times higher than that at 300 keV. These findings are crucial for advancing the study of thick biological and semiconductor samples using MeV-STEM.

• Research Organization: Brookhaven National Laboratory (BNL), Upton, NY (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities (SUF); USDOE Office of Science (SC), Biological and Environmental Research (BER); USDOE Office of Science (SC), Office of Workforce Development for Teachers & Scientists (WDTS)
• Grant/Contract Number: SC0012704
• OSTI ID: 2507149
• Report Number(s): BNL--227519-2025-JAAM
• Journal Information: Applied Sciences, Journal Name: Applied Sciences Journal Issue: 2 Vol. 15; ISSN 2076-3417
• Publisher: MDPICopyright Statement
• Country of Publication: United States
• Language: English