نتایج جستجو برای: ray spectra
تعداد نتایج: 397524 فیلتر نتایج به سال:
A novel sample holder is introduced which allows for temperature dependent soft x-ray absorption spectroscopy of liquids in transmission mode. The setup is based on sample cells with x-ray transmissive silicon nitride windows. A cooling circuit allows for temperature regulation of the sample liquid between -10 °C and +50 °C. The setup enables to record soft x-ray absorption spectra of liquids i...
CeBr3 crystals have been studied to assess their utility as potential gamma ray spectrometers for future ESA planetary missions. Pulse height spectra, scintillation time profiles, X-ray excited emission spectra, and photoluminescence spectra have been recorded as a function of temperature between 78 and 600 K. In addition, the influence of exposing CeBr3 to various doses of gamma rays from a st...
We present photoionization models accounting for both photoelectric and resonant absorption. We demonstrate that resonance absorption lines are detectable even in moderate resolution X-ray spectra of type 1 AGN. The spectra transmitted by gas illuminated by the ionizing continua typical of flat X-ray spectrum, broad optical emission line type 1 AGN, and steep X-ray spectrum, narrow optical emis...
The ROSAT All-Sky Survey observations of the complete hard X-ray selected Piccinotti AGN sample demonstrate that the soft X-ray spectra of almost none of the sample AGN can be simply represented by the power law extrapolated from the 2 10 keV range. A comparison of the soft X-ray spectra of the sample members with their medium energy continua measured with HEAO-1 and EXOSAT revealed that about ...
Owing to its element specific and short-range nature, core-level X-ray absorption spectroscopy (XAS) is now routinely used to elucidate the local structural, vibrational, and other physical properties of complex, aperiodic materials. XAS encompasses both extended X-ray absorption fine structure (EXAFS) and X-ray absorption near edge spectra (XANES) [1, 2], where the terms refer, respectively, t...
Aims. A model to describe cosmic ray spectra in the energy region from 10 11 up to 10 17 eV is suggested. It bases on the preposition that Galactic cosmic ray flux is a mixture of fluxes, accelerated by shocks from nova and supernova explosions of different types. Methods. We analyze recent experimental data on cosmic ray spectra obtained in direct measurements above the atmosphere and data obt...
We have developed a model which aims to reproduce observational data of many kinds related to cosmic-ray origin and propagation: direct measurements of nuclei, antiprotons, electrons and positrons, γ-rays, and synchrotron radiation. Our main results include evaluation of diffusion/convection and reacceleration models, estimates of the halo size, calculations of the interstellar positron and ant...
INTRODUCTION We directly measured diagnostic X-ray photon spectra produced by a single-phase 2-pulse diagnostic X-ray unit driven at 50 to 100 kV and a few mA(1), a mammographic X-ray unit at 25 to 32 kV and 3 times of 80 mAs(2) and an X-ray computed tomography (CT) scanner at 120 kV and 3 mA(3) have been analyzed. Since detected spectra were distorted by the response of CdZnTe(CZT) detector an...
The B̃-X̃ laser-induced-fluorescence spectrum of jet-cooled isopropoxy radical (i-C3H7O[middle dot]) has been recorded. Using an isolated state model the observed rotational and fine structure of the origin band has been well simulated to determine rotational constants for both the X̃ and B̃ states and the electron spin-rotation constants of the X̃ state. The line intensities are well simulated with...
We report on the first high-resolution measurements of the K x-ray resonant Raman scattering (RRS) in Si. The measured x-ray RRS spectra, interpreted using the Kramers-Heisenberg approach, revealed spectral features corresponding to electronic excitations to the conduction and valence bands in silicon. The total cross sections for the x-ray RRS at the 1s absorption edge and the 1s-3p excitation...
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