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Incident Electrons (incident + electron)

Distribution by Scientific Domains

Physics and Astronomy	40%
Chemistry	40%

Selected Abstracts

Design of A Soft X-ray Source with Periodic Microstructure Using Resonance Transition Radiation for Tabletop Synchrotron

IEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING, Issue 3 2008
Koji Sugano Member
Abstract A soft X-ray source with a periodic aluminum multilayer structure with vacuum layers in between for tabletop synchrotrons with low-energy electrons was designed, and the dependence of radiation performance on structural parameters was clarified using a theoretical calculation of the resonance transition radiation. A photon density of 1 keV pr incident electron was calculated by optimizing the thickness of the aluminum and vacuum layers. Furthermore, the designed structure was fabricated by a microfabrication technique. The effects of dimensional error on the photon density are discussed on the basis of the calculated results and the prototype structure of a 6-MeV synchrotron. It is clarified that dimensional errors of 1.5% in Al layers and of plus or minus a few dozen nanometers in the vacuum layers are negligible in obtaining a photon density of more than 90% of the maximum value. © 2008 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source]

Metastable anion fragmentations after resonant attachment: Deoxyribosic structures from quantum electron dynamics

INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 11 2008
I. Baccarelli
Abstract This work is focussed on the theoretical investigation of the observed fragmentation after the resonant electron attachment to gas-phase ,- D -deoxyribose. The collision energy of the incident electron is kept below 20 eV and both the furanosic and the pyranosic forms of the gaseous target are analyzed. All the transient negative ions associated to shape resonances are characterized in their energetics and spatial features, all pointing to highly selective bond-breaking resonant processes. The present results, when compared with the available experiments on gas-phase ,- D -deoxyribose and with the findings on the analogous conformers from the previously studied ,- D -ribose, offer new insights into the manifold fragmentation pathways occurring in biomolecules after electron attachment. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008 [source]

Electron beam irradiation of porous silicon for application in micromachining and sensing

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 8 2005
S. Borini
Abstract We have studied the effect of the electron beam (EB) irradiation on porous silicon (PS), in order to find new possibilities for the local modification of the material at the submicrometer scale. The interaction between the accelerated electrons and PS has been investigated by means of two main techniques: infrared spectroscopy and profilometric measurements. All the results show that a strong increase of reactivity is induced on PS surface under exposure to the EB, due to the hydrogen desorption provoked by the incident electrons. We demonstrate that this phenomenon can be exploited for both the lateral structuring and the local functionalization of PS, at the submicrometer scale, depending on the different treatments applied to the samples after the EB bombardment. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Interband transmission in armchair graphene ribbons with a step-like profile of potential energy: Relevance to Klein's tunneling

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 11-12 2009
Lyuba Malysheva
Abstract Three principal results concerning graphene-based wires and their ambipolar behavior are presented. First, it is the exact expression of the transmission coefficient for armchair graphene wires described by the tight-binding Hamiltonian with the step-like change U of site energies. Second, the exact relation between the energy of incident electrons or holes and potential U at which there is no backscattering for the given mode of the transverse motion. Third, the range of relevance of Klein's formula describing the motion of relativistic particles in the same potential profile is established. Analysis of newly derived results shows that physics of interband transitions at constant energy in graphene wires is richer than it was believed. [source]

Elastic scattering of high-energy electrons by dopant atoms within a crystal in transmission electron microscopy

ACTA CRYSTALLOGRAPHICA SECTION A, Issue 6 2008
B. G. Mendis
A Bloch-wave model of dopant-atom scattering is developed using perturbation theory for parallel illumination in a transmission electron microscope. Dopant-atom scattering causes a change in the Bloch-wave excitations, with transitions from one Bloch state to another being governed by the amplitudes of the Bloch states at the dopant-atom position. The scattering mechanisms therefore depend on whether the dopant atom is substitutional or interstitial as well as the orientation of the crystal. The model is used to calculate the electron wavefunction for substitutional and interstitial Mo atoms in [111]- and [001]-oriented body-centred cubic Fe and the results overall are consistent with multislice simulations. However, subtle differences are also observed. For example, in the Bloch-wave model the phase change of the incident electrons (with respect to the perfect crystal) due to dopant-atom scattering varies with the crystallographic orientation while in multislice theory the phase change is constant. This is likely to be due to the assumptions made in the Bloch-wave model, such as neglect of elastic diffuse scattering. Apart from providing a fundamental understanding of dopant-atom scattering, the model can also potentially be extended to analyse dopant-atom imaging in a scanning transmission electron microscope. [source]