Topic
Synchrotron radiation
About: Synchrotron radiation is a research topic. Over the lifetime, 14639 publications have been published within this topic receiving 244775 citations. The topic is also known as: magnetobremsstrahlung radiation & Synchrotron Radiation.
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TL;DR: X-ray photon correlation spectroscopy (XPCS) as mentioned in this paper is a novel technique for the study of slow dynamics in disordered materials that overcomes limitations of visible light scattering techniques such as multiple scattering or limitations in Q-range by using coherent X-rays from third generation synchrotron radiation sources.
146 citations
TL;DR: In this article, an adaptive mesh refinement simulation of the magnetohydrodynamic evolution of a galaxy cluster from cosmological initial conditions is used to locate shock fronts and apply models of cosmic-ray electron acceleration that are then input into radio emission models.
Abstract: Non-thermal radio emission from cosmic-ray electrons in the vicinity of merging galaxy clusters is an important tracer of cluster merger activity, and is the result of complex physical processes that involve magnetic fields, particle acceleration, gas dynamics, and radiation. In particular, objects known as radio relics are thought to be the result of shock-accelerated electrons that, when embedded in a magnetic field, emit synchrotron radiation in the radio wavelengths. In order to properly model this emission, we utilize the adaptive mesh refinement simulation of the magnetohydrodynamic evolution of a galaxy cluster from cosmological initial conditions. We locate shock fronts and apply models of cosmic-ray electron acceleration that are then input into radio emission models. We have determined the thermodynamic properties of this radio-emitting plasma and constructed synthetic radio observations to compare observed galaxy clusters. We find a significant dependence of the observed morphology and radio relic properties on the viewing angle of the cluster, raising concerns regarding the interpretation of observed radio features in clusters. We also find that a given shock should not be characterized by a single Mach number. We find that the bulk of the radio emission comes from gas with T > 5 ? 107 K, ? ~ 10?28-10?27 g cm?3, with magnetic field strengths of 0.1-1.0 ?G, and shock Mach numbers of . We present an analysis of the radio spectral index which suggests that the spatial variation of the spectral index can mimic synchrotron aging. Finally, we examine the polarization fraction and position angle of the simulated radio features, and compare to observations.
146 citations
TL;DR: In this paper, the normalized area of a pre-edge peak (bound-state transition) in X-ray absorption near-edge structure (XANES) spectra acquired with the synchrotron Xray microprobe on beam line X26A was used for the quantification of first-row transition metal species present as tetrahedral oxyanions.
Abstract: X-ray absorption near-edge structure (XANES) has been applied to the quantitative analysis of chromate (CrO[sub 4][sup 2[minus]]) content in oxides, silicate glasses, and simulated cementitous waste forms. The method uses the normalized area of a pre-edge peak (bound-state transition) in XANES spectra acquired with the synchrotron X-ray microprobe on beam line X26A at the National Synchrotron Light Source. The estimated accuracy of the technique is [+-] 5% in terms of Cr[sup 6+]/total Cr. The minimum detection limit approaches 10 ppm Cr[sup 6+] using a 150-[mu]m synchrotron X-ray beam. These results demonstrate the value of synchrotron-based microXANES for the nondestructive quantification of the first-row transition metal species present as tetrahedral oxyanions. 12 refs., 3 figs., 3 tabs.
145 citations
TL;DR: In this article, the first observation of 4.4 eV photoluminescence (PL) decay in an oxygen-deficient-type silica excited with ultraviolet and vacuum ultraviolet photons from synchrotron radiation is presented.
Abstract: We present the first observation of 4.4 eV photoluminescence (PL) decay in an oxygen-deficient-type silica excited with ultraviolet and vacuum ultraviolet photons from synchrotron radiation. The lifetime of the 4.4 eV PL is 4.2, 4.3, and 2.1 ns for the 5.0, 6.9, and 7.6 eV excitations, respectively, indicating the presence of multiple decay channels. This can be explained by an energy diagram involving the interconversion between two states of the oxygen-deficient-type defect.
145 citations