A new scheme for injection and acceleration of electrons in wakefield accelerators is suggested based on the co-action of a laser pulse and an electron beam. This synergy leads to stronger wakefield generation and higher energy gain in the bubble regime. The strong deformation of the whole bubble leads to electron self-injection at lower laser powers and lower plasma densities. To predict the practical ranges of electron beam and laser pulse parameters an interpretive model is proposed. The effects of altering the initial electron beam position on self-trapping of plasma electrons are studied. It is observed that an ultra-short (25 fs), high charge (340 pC), 1 GeV electron bunch is produced by injection of a 280 pC electron beam in the decelerating phase of the 75 TW laser driven wakefield.
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http://dx.doi.org/10.1038/s41598-020-79556-9 | DOI Listing |
ACS Nano
January 2025
School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China.
Twisted halide perovskite bilayers, a type of moiré material, show square moiré patterns with exciting optical properties. Atomic-scale structure analysis and its correlation with properties are difficult to achieve due to the extreme sensitivity of organic-inorganic halide perovskites to the illuminated electron beam in conventional/scanning transmission electron microscopy. Here, we developed a low-dose exit wave reconstruction methodology with a real-space resolution of one angstrom at ∼50 e/Å, which recovers the phase information on the moiré fringes in CHNHPbI (MAPbI) twisted perovskite bilayers at atomic scale, enabling detailed structural analysis of defects and corresponding strain distribution in such moiré materials.
View Article and Find Full Text PDFSci Adv
January 2025
National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, China.
Revealing the momentum-resolved electronic structure of infinite-layer nickelates is essential for understanding this class of unconventional superconductors but has been hindered by the formidable challenges in improving the sample quality. In this work, we report the angle-resolved photoemission spectroscopy of superconducting LaSrNiO films prepared by molecular beam epitaxy and in situ atomic-hydrogen reduction. The measured Fermi topology closely matches theoretical calculations, showing a large Ni [Formula: see text]-derived Fermi sheet that evolves from hole-like to electron-like along and a three-dimensional (3D) electron pocket centered at the Brillouin zone corner.
View Article and Find Full Text PDFJ Chem Phys
January 2025
Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria.
Thiazole derivatives are biologically relevant molecules, used also in pharmaceutical applications. Herein, we report results for electron attachment to 2-bromo-5-nitrothiazole (BNT) in the gas phase. Employing two crossed electron-molecule beam experiments, we determined the efficiency curves of various fragment anions as a function of the initial electron energy between about 0 and 10 eV as well as the emission angle and kinetic energy distributions of Br- and NO2- ions formed from a resonance near 4 eV.
View Article and Find Full Text PDFACS Biomater Sci Eng
January 2025
CEA, DES, ISEC, DPME, SEME, University of Montpellier, Marcoule, Bagnols-sur-Cèze F-30207, France.
Although models have been proposed to explain the mechanisms of bioglass (BG) dissolution and subsequent calcium phosphate (CaP) mineralization, open questions remain. The processes in which phase transition occurs in aqueous solutions and their dynamics remain underexplored partly because traditional instruments/techniques do not allow for direct observations at the adequate time and length scales at which such phase transformations occur. For instance, given the crucial role of the silica gel in CaP formation during BG dissolution, uncertainty exists about how such a silica gel forms on the BG surface.
View Article and Find Full Text PDFBeilstein J Nanotechnol
January 2025
Physics Institute, Goethe University Frankfurt, Max-von-Laue-Str. 1, 60438 Frankfurt am Main, Germany.
A fast simulation approach for focused electron beam induced deposition (FEBID) numerically solves the diffusion-reaction equation (continuum model) of the precursor surface on the growing nanostructure in conjunction with a Monte Carlo simulation for electron transport in the growing deposit. An important requirement in this regard is to have access to a methodology that can be used to systematically determine the values for the set of precursor parameters needed for this model. In this work we introduce such a method to derive the precursor sticking coefficient as one member of the precursor parameter set.
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