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The demand for high-throughput electron tomography is rapidly increasing in biological and material sciences. However, this 3D imaging technique is computationally bottlenecked by alignment and reconstruction which runs from hours to days. We demonstrate real-time tomography with dynamic 3D tomographic visualization to enable rapid interpretation of specimen structure immediately as data is collected on an electron microscope. Using geometrically complex chiral nanoparticles, we show volumetric interpretation can begin in less than 10 minutes and a high-quality tomogram is available within 30 minutes. Real-time tomography is integrated into tomviz, an open-source and cross-platform 3D data analysis tool that contains intuitive graphical user interfaces (GUI), to enable any scientist to characterize biological and material structure in 3D. High-throughput electron tomography has been challenging due to time-consuming alignment and reconstruction. Here, the authors demonstrate real-time tomography with dynamic 3D tomographic visualization integrated in tomviz, an open-source 3D data analysis tool. [ABSTRACT FROM AUTHOR]

This article focuses on the development of a transparent and uniform understanding of possibilities for three-dimensional (3D) imaging in scanning transmission and confocal electron microscopes (STEMs and SCEMs), with an emphasis on the annular dark-field STEM (ADF-STEM), bright-field SCEM (BF-SCEM), and ADF-SCEM configurations. The incoherent imaging approximation and a 3D linear imaging model for ADF-STEM are reviewed. A 3D phase contrast model for coherent-SCEM as well as a pictorial way to find boundaries of information transfer in reciprocal space are reviewed and applied to both BF- and ADF-SCEM to study their 3D point spread functions and contrast transfer functions (CTFs). ADF-STEM is capable of detecting the depths of dopant atoms in amorphous materials but can fail for crystalline materials when channeling substantially modifies the electron propagation. For the imaging of extended (i.e., nonpointlike) features, ADF-STEM and BF-SCEM exhibit strong elongation artifacts due to the missing cone of information. ADF-SCEM shows an improvement over ADF-STEM/BF-SCEM due to its differential phase contrast eliminating slowly varying backgrounds, an effect that partially suppresses the elongation artifacts. However, the 3D CTF still has a cone of missing information that will result in some residual feature elongation as has been observed in A. Hashimoto et al., J Appl Phys 160(8), 086101 (2009). [ABSTRACT FROM AUTHOR]

Electron energy loss fine structure near the threshold of inner-shell edges can potentially give valuable information on bonding on an atomic scale. To use near-edge structure it is essential to understand what factors influence both the occupied and unoccupied local density of states in the material of interest. Different techniques of electronic structure theory are suitable for metals, semiconductors, and ionic materials, although some methods can be applied to a wide range of systems. To extract quantitative information on bonding it is important to avoid those edges that are strongly affected by the presence of the core hole such as cations in ionic materials. [ABSTRACT FROM AUTHOR]