The research in this thesis is focused on tomographic reconstruction based on two imaging modalities in electron microscopy. The first modality is high angle annular dark field scanning... Show moreThe research in this thesis is focused on tomographic reconstruction based on two imaging modalities in electron microscopy. The first modality is high angle annular dark field scanning transmission microscopy (HAADF-STEM), and the second modality is energy-dispersive X-ray spectroscopy (EDS). In this Ph.D. thesis, we propose several approaches to pave the way for HAADF- STEM + EDS tomography: (1) the HAADF-EDS bimodal tomographic reconstruction technique, which is based on jointly modeling the consistency of the two imaging modalities; (2) TNV-regularized joined reconstruction which allows to incorporate the prior knowledge that common edges exist in the reconstructions from HAADF and EDS data respectively; (3) a set of algorithmic recipes to tailor various reconstruction algorithms for given experimental conditions and sample properties; (4) an algorithm for automatically correcting the nonlinear damping effects in HAADF-STEM tomographic data. Show less
Electron microscopy has become an extremely important techniquein a wide variety of elds. The resolving power is vastly superiorto light microscopes and electron microscopy has proven tobe valuable... Show moreElectron microscopy has become an extremely important techniquein a wide variety of elds. The resolving power is vastly superiorto light microscopes and electron microscopy has proven tobe valuable in elds ranging from archaeology and geology to biology andcondensed-matter physics.A major disadvantage is that the electron energy used in conventional ElectronMicroscopy (EM) ranges from 10’s to 100’s of keV. Such energetic electronscan signicantly damage the specimen. This is especially relevant in thestudy of biological samples and organic materials in general. Major eorts arebeing made to avoid this radiation damage from interfering with the studyof such materials. There are several approaches to minimize damage in EM.These include developing better detectors such that lower electron doses aresucient to form an image, and lowering the electron energies to several keV.In this dissertation I present the development of, and measurements with, atransmission electron microscope that uses electron energies ve orders ofmagnitude lower than in conventional Transmission Electron Microscopes(TEMs). The energies we use are in the order of a few eV. Hence, we call ourtechnique ’eV-TEM’. Show less
In this thesis the combinatorial use of bioorthogonal labelling and Electron Microscopy (EM)-based imaging techniques is explored to enable observations of specific molecular targets in their... Show moreIn this thesis the combinatorial use of bioorthogonal labelling and Electron Microscopy (EM)-based imaging techniques is explored to enable observations of specific molecular targets in their ultrastructural context within the cell. Show less
