Search results for "X-ray spectra"

showing 3 items of 3 documents

Overionization in X-ray spectra: a new paradigm for Mixed-Morphology SNRs

2011

Mixed-morphology SNRs are characterized by a shell-like radio emission, a centrally peaked X-ray morphology, and by interaction with molecular clouds. Many models have been proposed to explain these peculiar remnants, but their physical origin is still unclear. The recent discovery of over-ionized (i. e. recombining) ejecta in 3 mixed-morphology SNRs has dramatically challenged all the previous models and opened up new, unexpected scenarios. I review the main properties of these remnants and their peculiar X-ray spectral properties. I also discuss the hydrodynamic model developed to explain the presence of over-ionized ejecta in W49B and present a list of open issues that still need to be c…

High Energy Astrophysical Phenomena (astro-ph.HE)Astrophysics::High Energy Astrophysical PhenomenaFOS: Physical sciencesAstrophysics - High Energy Astrophysical PhenomenaMixed-morphology SNRs are characterized by a shell-like radio emission a centrally peaked X-ray morphology and by interaction with molecular clouds. Many models have been proposed to explain these peculiar remnants but their physical origin is still unclear. The recent discovery of overionized (i. e. recombining) ejecta in 3 mixed-morphology SNRs has dramatically challenged all the previous models and opened up new unexpected scenarios. I review the main properties of these remnants and their peculiar X-ray spectral properties. I also discuss the hydrodynamic model developed to explain the presence of overionized ejecta in W49B and present a list of open issues that still need to be clarified.Astrophysics::Galaxy Astrophysics
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EBIT diagnostics using X-ray spectra of highly ionized Ne

2003

We have carried out a detailed analysis of highly ionized neon spectra collected at the NIST EBIT using an NTD germanium X-ray microcalorimeter developed at the Harvard-Smithsonian Center for Astrophysics [Nucl. Instr. and Meth. A 444 (2000) 156]. Our attention was focused especially on the Ne IX He-like triplet to check electron density diagnostics through the intercombination/forbidden line ratio. We have investigated possible effects of the ion dynamics on the plasma emission line intensities, looking at the dependence of the count-rate and the charge state distribution on the electron beam energy and current. The temperature and spatial distribution of the neon ions, and hence the overl…

X-ray spectraNuclear and High Energy PhysicsElectron densityEBITChemistrySurfaces Coatings and Filmchemistry.chemical_elementFizikai tudományokSurfaces and InterfacesPlasmaIonNeonSettore FIS/05 - Astronomia E AstrofisicaTermészettudományokIonizationAstrophysical plasmaPhysics::Atomic PhysicsEmission spectrumAtomic physicsIonization of atomForbidden mechanismInstrumentationExcitation
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FLUXEN portable equipment for direct X-ray spectra measurements

2004

Abstract The proper use of imaging equipment in radiological units is based on an appropriate knowledge of the physical characteristics of the X-ray beam used. The FLUXEN PROJECT is working on a portable apparatus which, together with dedicated software, is able to perform an exact spectral reconstruction of the radiation produced in diagnostic X-ray tubes. The apparatus characterizes the energy spectrum of radiological tubes and also provides a measurement of the emitted flux. The acquisition system is based on a commercial CZT detector (3×3×2 mm 3 ), produced by AMPTEK, cooled by a Peltier cell, with a high efficiency in the diagnostic X-ray energy range and modified in the shaping electr…

PhysicsNuclear and High Energy PhysicsRange (particle radiation)X-ray spectraX ray spectrographs X rays air kerma CZTbusiness.industryRadiationSignalSpectral lineCZTOpticsSoftwareX-ray spectra; direct measurement; CZTElectronicsdirect measurementbusinessInstrumentationBeam (structure)Energy (signal processing)
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