Search results for "beam [electron]"
showing 10 items of 433 documents
Growth of low-density vertical quantum dot molecules with control in energy emission
2010
This article is distributed under the terms of the Creative Commons Attribution Noncommercial License.-- This article is part of the series 8th International Workshop on Epitaxial Semiconductors on Patterned Substrates and Novel Index Surfaces.
Initial stages of self-assembled InAs/InP(001) quantum wire formation
2007
4 páginas, 2 figuras.-- PACS codes: 78.67.Lt; 68.65.La; 68.37.Ps.-- Comunicación oral presentada a la 14ª International Conference on Molecular Beam Epitaxy - MBE XIV celebrada en Tokio (Japón) del 3 al 8 de Septiembre de 2006.
Size filtering effect in vertical stacks of In(Ga)As/GaAs self-assembled quantum rings
2006
3 páginas, 3 figuras.
A beam element allowing multiple slope discontinuities for RC structures: An application
2018
A beam/column element allowing the formation of multiple plastic hinges in columns or beams of a reinforced concrete (RC) framed structure is used in this work to show, through an application, its advantages with respect to conventional lumped plasticity models. Slope discontinuities can be located at any position of an Euler-Bernoulli beam span and not at the two extremes only. The model is in fact written in the framework of a modified lumped plasticity theory, and respectful of a thermodynamic approach. Flow rules and state equations are derived invoking the Theorem of maximum dissipation and using a Bresler's type activation domain. The beam element has already been implemented in a res…
Development of an MeV ion beam lithography system in Jyväskylä
2007
Abstract A lithographic facility for writing patterns with ion beams from cyclotron beams is under development for the Jyvaskyla cyclotron. Instead of focusing and deflecting the beam with electrostatic and magnetic fields a different approach is used. Here a small rectangular beam spot is defined by the shadow of a computer-controlled variable aperture in close proximity to the sample. This allows parallel exposure of rectangular pattern elements of 5–500 μm side with protons up to 6 MeV and heavy ions (20Ne, 85Kr) up to few 100 MeV. Here we present a short overview of the system under construction and development of the aperture design, which is a critical aspect for all ion beam lithogra…
Aperture edge scattering in focused MeV ion beam lithography and nuclear microscopy: An application for the GEANT4 toolkit
2009
Collimators are widely used to define MeV ion beams. Recent studies have shown the capability of combinations of collimators and lenses to define beams of MeV ions with sub-100 nanometre dimensions. Such nanometre beams have potential applications in MeV ion beam lithography, which is the only maskless technique capable of producing extremely high aspect ratio micro- and nano-structrures, as well as in high resolution MeV ion beam based imaging. The ion scattering from the collimator-edges can be a resolution restricting factor in these applications. Scattering processes at edges are difficult to study using conventional simulation codes because of the complicated geometry. In this work we …
A pulsed high-voltage decelerator system to deliver low-energy antiprotons
2021
International audience; The GBAR (Gravitational Behavior of Antihydrogen at Rest) experiment at CERN requires efficient deceleration of 100 keV antiprotons provided by the new ELENA synchrotron ring to synthesize antihydrogen. This is accomplished using electrostatic deceleration optics and a drift tube that is designed to switch from -99 kV to ground when the antiproton bunch is inside – essentially a charged particle “elevator” – producing a 1 keV pulse. We describe the simulation, design, construction and successful testing of the decelerator device at -92 kV on-line with antiprotons from ELENA.
Fabrication of a negative PMMA master mold for soft-lithography by MeV ion beam lithography
2012
Abstract In this study, poly(methyl methacrylate) (PMMA) was investigated as a negative resist by irradiation with a high-fluence 2 MeV proton beam. The beam from a 1.7 MV Tandetron accelerator at the Plasma and Beam Physics Research Facility (PBP) of Chiang Mai University is shaped by a pair of computer-controlled L-shaped apertures which are used to expose rectangular pattern elements with 1–1000 μm side length. Repeated exposure of rectangular pattern elements allows a complex pattern to be built up. After subsequent development, the negative PMMA microstructure was used as a master mold for casting poly(dimethylsiloxane) (PDMS) following a standard soft-lithography process. The PDMS chi…
Measurement of high energy resolution inelastic proton scattering at and close to zero degrees
2009
13 pages, 15 figures.-- Printed version published Jul 1, 2009.
Application and development of ion-source technology for radiation-effects testing of electronics
2017
Abstract Studies of heavy-ion induced single event effect (SEE) on space electronics are necessary to verify the operation of the components in the harsh radiation environment. These studies are conducted by using high-energy heavy-ion beams to simulate the radiation effects in space. The ion beams are accelerated as so-called ion cocktails, containing several ion beam species with similar mass-to-charge ratio, covering a wide range of linear energy transfer (LET) values also present in space. The use of cocktails enables fast switching between beam species during testing. Production of these high-energy ion cocktails poses challenging requirements to the ion sources because in most laborat…