M. Horstmann

Bio: M. Horstmann is an academic researcher from University of Hamburg. The author has contributed to research in topics: Scattering & Atmospheric temperature range. The author has an hindex of 5, co-authored 9 publications receiving 81 citations.

Eine Gegenfeldanordnung zur Messung von Energie- und Winkelverteilungen gestreuter Elektronen

Abstract: In a previous paper direct electron-intensity measurements in Debye-Scherrer diagrams of aluminium have been described. A retarding field apparatus was used for investigations into the influence of crystal size and electron energy (15 to 50 keV) on the elastic diffraction intensities. The validity range of the kinematical theory could be determined. By means of a retarding field the inelastically scattered electrons were separated from the elastically scattered electrons (energy loss below 2 eV). In this paper the retarding field apparatus by which scattering intensities can be measured with good accuracy (≈ 2%) is described in detail. It is compared with other arrangements for the measurements of angular and energy distributions of scattered electrons.

Messung der Elektronenbeugungsintensitäten polykristalliner Aluminiumschichten bei tiefer Temperatur und Vergleich mit der dynamischen Theorie

Abstract: By means of a retarding field apparatus the electron diffraction intensities of a polycrystalline Aluminium-foil have been measured for different electron energies between 17 and 50 kev. The specimen was kept at 154 °K and the thickness of the crystallites was about 280 A. It has been shown that the high index reflections behave kinematically, while the first order reflections [e.g. (111), (200)] are much influenced by dynamical extinction effects which can be explained very well by the dynamical two beam approximation.

Wirkungsquerschnitt und Winkelverteilung der elastischen und unelastischen Elektronenstreuung in Aluminiumschichten

Abstract: Absolute intensity measurements of the electrons scattered by a polycrystalline Aluminium foil were carried out in the energy range between 25 and 50 keV. The electrons scattered elastically were separated from those scattered inelastically by means of a retarding field. The intensities of the electrons having passed the foil unscattered and of those which were scattered elastically into the Debye-Scherrerrings and into the continuous background can be interpreted by the assumption of reasonable thicknesses of the crystalline Aluminium and the amorphous Aluminium-Oxide. These values agree approximately with the thickness measured by light absorption. Additionally the probability of the inelastic scattering process can be deduced from these measurements. Investigations of the angular distribution were carried out in order to study the influence of the inelastic scattering on the shape of the primary beam, the rings and the continuous background. The results are discussed in detail. Some results are given in particular, concerning the increase of the half width of the rings due to inelastic scattering processes.

Einfluß der Kristalltemperatur auf die Intensitäten dynamischer Elektroneninterferenzen

Abstract: The temperature dependence of dynamically influenced electron diffraction intensities of a polycrystalline aluminium foil was measured by means of a retarding field apparatus in the temperature range 150–800°K. It is shown, that the observed temperature behaviour of these reflections (g) can be described by effective Debye Waller factors exp(- αM)g, which are in good agreement with calculations, based on the dynamical theory of electron diffraction.

Messung der Intensitäten von elastisch und unelastisch gestreuten Elektronen mit einer Gegenfeldanordnung

Abstract: A retarding field apparatus for the measurement of angular and energy distributions of scattered electrons (15 to 50 keV) is described. The apparatus was used for investigations into the influence of crystal size and electron energy on the elastically scattered intensity in Debye-Scherrer-diagramms of aluminium. The results are discussed with respect to the dynamical and kinematical theory. It proves, that the kinematical theory does not hold for crystallites of 100 A thickness or more.

Energy-filtering transmission electron microscopy

Abstract: Publisher Summary In energy-filtering transmission electron microscopy (EFTEM), the zero-loss electrons or electrons passing an energy-loss window of the electron energy-loss spectroscopy (EELS) are used for image formation. This can be achieved by using the scanning mode in a dedicated scanning transmission electron microscope (STEM) or in a TEM with a spectrometer behind the camera chamber or by using an imaging filter lens in the column of a TEM. The conventional TEM and STEM modes can be combined in this way with the mode of electron spectroscopic imaging (ESI) and electron spectroscopic diffraction (ESD), and different modes can be used to record an EELS spectrum. An EFTEM can therefore make full use of elastic and inelastic electron-specimen interactions. This chapter provides an overview of the physical background and the possibilities of EFTEM. The relevant physics of elastic and inelastic scattering is also discussed followed by the instrumentation of EFTEM. The theoretical approaches for understanding the contrast and examples of application are presented for ESI and for ESD.

Electron Slowing-Down Spectra in Solids'

Abstract: Some theoretical methods used to describe the interaction of electrons with metals, semiconductors, and insulators are reviewed. Calculations of electron slowing-down spectra using these methods are presented for Al, Cu, Cr, Si, and Al$sub 2$O$sub 3$. Experimental electron slowing-down spectra for these materials are also presented and comparisons with theoretical calculations are discussed. 40 refs. (auth)