Scanning Electron Microscope Solid State Detectors

Solid state detectors (SSD) are the most commonly used backscattered electron (BSE) detectors in scanning electron microscopy (SEM). They have been used for at least 20 years and many types are described in the literature. These detectors can be designed in many shapes and forms but in commercially available SEMs two semiconductor detectors (A and B) are usually placed below the polepiece where they are used for compositional (A+B) and topographic (A-B) contrast enhancement. The range of SSD applications available from BSE is quite extensive. The kind and quality of information depend strongly on the shape and position of the detector in relation to the specimen and the electron beam. Also very important is the current gain vs. electron energy dependence, which can be controlled by detector manufacturing technology. This paper reviews various possible applications of semiconductor detectors in SEM, as well as factors which influence the quality of information obtainable from BSE by semiconductor detectors

Some Applications of the Electron Backscattering Diffusion Model

Starting from a simple diffusion theory extended to oblique angles of incidence some empirical correction coefficients for electron backscattering have been found. These empirical coefficients have been used in calculations of backscattered electron surface density distribution, and good agreement with experimental data has been obtained

Signal Mixing Technique for Backscattered Electrons in the Scanning Electron Microscope

Signal mixing technique using asymetrically placed backscattered electron detectors in a scanning electron microscope is presented in this paper. Two types of detectors have been used: a low-take off angle ring scintillation detector (placed around the specimen) and a wide-angle semiconductor detector (placed above the specimen). It has been shown that the discussed configuration gives good real topography in all directions on the specimen surface and also reduces significantly the pseudo-topography effect of flat grain boundaries

Uwarunkowania społeczno-ekonomiczne budownictwa mieszkaniowego w Poznaniu

Wydział Nauk Geograficznych i Geologicznych: Instytut Geografii Społeczno-Ekonomicznej i Gospodarki Przestrzenne

Backscattering of Electrons from Complex Structures

The backscattering of electrons from complex targets (for example, metal layer on a semi-infinite substrate with a polymer resist film above) has been studied both theoretically and experimentally. The experimental structures were exposed with an electron beam in a spot mode . The experimental observations of developed disc radius vs. exposure time and metal layer thickness support the simple theory of scattering in such structures. The theory assumes that the backscattering causes enlarging of the exposed area by a constant value. This value is derived from the proposed scattering model based on the Archard\u27s and Kanaya and Okayama\u27s diffusion theories. The radial exposure intensity distribution introduced by the electron beam has been approximated by a Gaussian function

Reurbanisation in Postsocialist Europe - A Comparative View of Eastern Germany, Poland, and the Czech Republic

Since the 1990s, reurbanisation has become an increasingly frequent trajectory for urban development. Many formerly shrinking cities have been able to stabilise their population or even see new growth. Especially prominent in regions like Germany and the UK, but also observed across the whole continent, a lively debate on reurbanisation has developed as a reality of today’s, and a potential trajectory for tomorrow’s, cities in Europe. Postsocialist Europe has not so far been central in the reurbanisation debate, either empirically or theoretically. Subsequently, the postsocialist experience is missing in the discourse and the existing body of evidence. There is, however, some evidence that Czech and Polish cities are also seeing signs of new inner-city growth and a trend towards core city stabilisation. Against this background, the paper scrutinises the issues of reurbanisation and new growth after the shrinking of postsocialist cities. The paper uses the approach of a contrastive comparison between cities in eastern Germany, where reurbanisation has developed as the predominant trajectory for many large cities, and for cities in Poland and the Czech Republic, where this trend is considerably less prominent. It analyses the development of reurbanisation in these cities and their urban regions over the last few decades, its characteristics and the determinants triggering or impeding it. The paper includes data on a national scale as well as from relevant case studies of cities and their urban regions. It argues, among other things, that there is no "postsocialist model" with regard to influencing factors for reurbanisation. Eastern Germany, due to its specific postsocialist situation and transformation trajectory, can be viewed as an "outlier" or "hybrid" which exhibits characteristics typical of postsocialist and western welfare contexts and which is seeing especially dynamic reurbanisation after a phase of extreme shrinkage. Although there are clear signs of inner-city reurbanisation in Polish and Czech cities as well, it seems relatively unlikely that this process will reach the same high levels as in East German cities within the coming years