Inelastic scattering, electron-specimen interactions

Electrons which have lost energy by interaction with the specimen (inelastically scattered electrons) also exit the specimen. The amounts of energy lost by the electrons can be measured and form the basis for several types of electron energy-loss spectroscopies (EELS) which allow high-resolution chemical analysis to be performed. 

The interaction of the primary electrons with the specimen results in the emission of secondary electrons (SE), i.e., inelastically scattered electrons that escape from the sample and reach the respective detector if emitted per definition from a depth less than about 50 nm equivalent of solid phase (Figure 21.2). The resolutirm of the SE is determined by the quality of the focus of the primary beam and the area of the sample surface from which they are emitted. 

Electron-Specimen Interactions 29.2.3.3.1. Elastic and Inelastic Scattering... 

HRTEM exploits three different interactions of electron beam-specimen unscattered electrons (transmitted beam), elastically scattered electrons (diffracted beam) and inelastically scattered electrons. Different types of images are obtained in HRTEM. As a result, diffraction patterns are shown because of the scattered electrons. If the unscattered beam is selected, we obtain the Bright Field Image. Dark Field Images are obtained if beams are selected by the objective aperture. 

When a solid is bombarded with high energy electrons the interaction produces secondary electrons (elastic), back-scattered electrons (inelastic), low loss electrons. Auger electrons, photo electrons, electron diffraction, characteristic x-rays, x-ray continuum, light, hole electron pairs and specimen current. These interactions are used to identify the specimen and elements of the specimen and can also be used to physically characterize particulate systems. 

Kikuchi lines result from inelastic scattering of electrons in specimens. Generally, an electron scatters elastically when it interacts with an atomic nucleus. The mass of a nucleus is much larger than that of an electron. Thus, their interaction is similar to a ball hitting wall where the ball bounces without energy loss. However, when the electron interacts with an electron in an atomic shell, energy will transfer between the two electrons during collision, which is referred... 

The fundamental theory of EDS is based on the production ofX rays as one of the resultant signals from specimen-beam interactions. As an electron from the beam interacts with electrons from atoms of the sample (inelastic scattering), it may knock an electron out of a shell. An electron from an outer shell will move into the inner shell and consequendy loses energy in the form of an X ray. Each element has characteristic X-ray energies based on the movement of electrons from an M shell to an L shell and an L shell to a K shell. Approximately 1 % of the... 

When a beam of charged particles passes through a thin specimen, the beam transmitted in the forward direction includes some particles that scattered elastically off atomic nuclei or lost energy due to interaction with electrons (inelastically scattered) as well as those particles that were left unscattered. An image formed with this forward-transmitted beam is referred to as a bright field image. 

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