Towards detecting swath events in TerraSAR-X time series to establish NATURA 2000 grassland habitat swath management as monitoring parameter

Spatial monitoring tools are necessary to respond to the threat of global biodiversity loss. At the European scale, remote sensing tools for NATURA 2000 habitat monitoring have been requested by the European Commission to fulfill the obligations of the EU Habitats Directive. This paper introduces a method by which swath events in semi-natural grasslands can be detected from multi-temporal TerraSAR-X data. The investigated study sites represent rare and endangered habitats (NATURA 2000 codes 6410, 6510), located in the Döberitzer Heide nature conservation area west of Berlin. We analyzed a time series of 11 stripmap images (HH-polarization) covering the vegetation period affected by swath (June to September 2010) at a constant 11-day acquisition rate. A swath detection rule was established to extract the swath events for the NATURA 2000 habitats as well as for six contrasting pasture sites not affected by swath. All swath events observed in the field were correctly allocated. The results indicate the potential to allocate semi-natural grassland swath events to 11-day-periods using TerraSAR-X time series. Since the conservation of semi-natural grassland habitats requires compliance with specific swath management rules, the detection of swath events may thus provide new parameters for the monitoring of NATURA 2000 grassland habitats.DLR/50EE092

Elastic scattering of intermediate-energy electrons from C-60 molecules

Experimental and calculated differential cross sections for elastic scattering of electrons by C60 molecules at collision energies of 100 to 500 eV are reported. The elastic differential cross sections were measured in a standard crossed-beam apparatus, while the calculations were performed employing the Schwinger multichannel technique at the static-exchange level. Diffraction effects, some due to the overall spherical-cage structure and some to scattering by individual C atoms, are observed in both the measured and calculated cross sections.L. R. Hargreaves, B. Lohmann, C. Winstead, and V. McKo

Elastic scattering of spin polarised electrons from krypton

No Full Tex

Dynamics in electron-impact ionization of H(2)O

We present multiply differential cross sections for electron-impact ionization of the water molecule. The experimental results are compared with theoretical cross sections calculated using a recently developed distorted-wave Born approach for molecules. The experimental cross sections exhibit a very large recoil scattering, which is not predicted by the theory. This has implications for applications of this theoretical approach in areas such as modeling of ionization in biological systems.D. S. Milne-Brownlie, S. J. Cavanagh, Birgit Lohmann, C. Champion, P. A. Hervieux, and J. Hansse

Studies of spin-polarized electron scattering from rubidium

A2 spin asymmetry measurements have been made for electron excitation of the 5S - 5P transition in atomic rubidium for incident electron energies of 20 eV and 30 eV. The data are compared with calculations from a semi-relativistic R-matrix Breit-Pauli model. Good qualitative agreement is obtained clearly demonstrating the existence of significant relativistic effects in the electron-atom interaction

Low-energy positron interactions with xenon

Low-energy interactions of positrons with xenon have been studied both experimentally and theoretically. The experimental measurements were carried out using a trap-based positron beam with an energy resolution of ̃80 meV, while the theoretical calculat

Fully differential cross-section measurements for electron-impact ionization of neon and xenon

We present a combined experimental and theoretical investigation of the fully differential cross section for electron-impact ionization of neon and xenon. The experiments were performed under coplanar asymmetric kinematics, at intermediate incident electron energies, and for a range of scattered electron detection angles. The experimental results are compared with three calculations: a convergent close-coupling calculation, a distorted-wave Born approximation (DWBA) calculation with inclusion of the Gamow factor, and a hybrid DWBA+R-matrix calculation. The comparison between the experimental and theoretical results highlights the importance of the description of postcollision interaction, and the results exhibit interesting orbital-dependent differences.M. A. Stevenson, L. R. Hargreaves, B. Lohmann, I. Bray, D. V. Fursa, K. Bartschat and A. Kheifet

Low energy inner valence ionization of the rare gases

Matthew A. Haynes, Birgit Lohmann, D. A. Biava, R. P. McEachran, C. T. Whelan, and D. H. Madiso

Spinresolved collisions of electrons with rubidium atoms: a search for relativistic effects

The search for relativistic effects in electron-alkali scattering is currently a topic of considerable interest. The A2 spin asymmetry parameter is a direct measure of relativistic effects in the electron-atom collision process, as it is entirely dependent on the spin-orbit effect. We present measurements of the A2 spin asymmetry for the 5S 5P transition in rubidium at incident energies of 15, 20, 30 and 50 eV and for elastic scattering at 15, 20, 30, 50 and 80eV. Our results indicate that under these collision conditions, relativistic effects are measurable, in qualitative agreement with the available theory

Ionization of Atoms with Spin Polarized Electrons

The most detailed insight into the process of electron impact-induced ionization of atomic species is provided by measurements in which both kinematical and quantum mechanical variables are determined. Here we describe recent (e,2e) experimental and theoretical studies involving the ionization of xenon and argon by spin-polarized electrons in which the fine-structure levels of the ion are energetically resolved. Such investigations shed light on the mechanisms driving the ionization reaction and the role of exchange and relativistic processes