Search results for "electromagnetic [radiation]"
showing 10 items of 873 documents
Chemical microimaging and microspectroscopy of surfaces with a photoemission microscope
1997
We applied element sensitive photoemission electron microscopy (PEEM) to investigate surfaces of devices built from complex materials. Conventional PEEM suffers from lack of information about the chemical composition of the imaged surface. Such information can be obtained by PEEM via tuning the photon energy to X-ray absorption edges. To apply spectromicroscopy we acquired and subtracted microscopic images using photon energies just below and at the edges. The resulting difference gives a micro-image of the lateral distribution of a specific element. Microspectroscopy is performed by recording the intensity of secondary electrons in selected spots during a sweep of the photon energy. We app…
<title>Iridium L<formula><inf><roman>3</roman></inf></formula>-edge and oxygen K-edge x-ray absorption spec…
2003
Structural investigations of the short range order around iridium and oxygen ions in nanocrystalline iridium oxide thin films, prepared by dc magnetron sputtering technique, were performed by x-ray absorption spectroscopy. The Ir L3-edge extended x-ray absorption fine structure and the O K-edge x-ray absorption near edge structure signals were measured at room temperature and analyzed within ab initio multiple-scattering and full-multiple-scattering approaches, respectively. The x-ray absorption spectroscopy results indicate the presence in the films of orderd regions - nanocrystals, having a size of about 10 angstrom and a structure rather close to that in crystalline iridium oxide IrO2. S…
High-pressure x-ray absorption spectroscopy study of tin tungstates
2015
Room-temperature pressure-dependent (0-25 GPa) x-ray absorption spectroscopy at the W -edges of α-SnWO4 and β-SnWO4 was performed using a dispersive setup and a high-pressure nanodiamond anvil cell. The detailed analysis of experimental x-ray absorption near-edge structure and extended x-ray absorption fine structure data suggests that upon increasing pressure, a displacement of tungsten atoms by about 0.2 A toward the center of the WO6 octahedra occurs in α-SnWO4, whereas the coordination of tungsten atoms changes from tetrahedral to distorted octahedral in β-SnWO4.
Local structure studies of SrTi16O3and SrTi18O3
2014
In this work we report on the local structure of Ti in SrTi 16 O3 (STO16) and SrTi 18 O3 (STO18) investigated in the low temperature range (6‐300K) by extended x-ray absorption fine structure and x-ray absorption near edge structure (XANES) spectroscopy at Ti K-edge and by optical second harmonic generation (SHG). By comparing XANES of STO16 and STO18 we have identified the isotopic effect which produces at T < 100K a noticeable difference in the measured mean square relative displacements (MSRD) of Ti‐O1 bonds: while STO16 follow the expected Einstein-like behavior, for STO18 we have measured an increase of MSRD values with decreasing temperature. This is an indication of an increasing off…
Determination of Kerr and two-photon absorption coefficients of indandione derivatives
2017
This material is based upon work supported by the ERDF 1.1.1.1 activity project Nr. 1.1.1.1/16/A/046 “Application assessment of novel organic materials by prototyping of photonic devices” as well as by National Research Program “Multifunctional Materials and Composites, Photonics and Nanotechnology” (IMIS2) project “Photonics and materials for photonics”.
<title>Advanced light sources for atomic absorption analysis</title>
2003
High-frequency electrodeless light sources (HF EDLS) are widely used as bright radiators of narrow and intensive atomic and ionic spectral lines, covering the spectrum from VUV to IR. Main characteristics of HF EDLS are high emitted spectral line intensity, long service life, and in general, narrow spectral line shapes because of low-pressure of filling elements. In this work we give a short overview of the use of HF EDLS, containing Hg, Te, Se, Zn, Pb, As, Sb, Bi, Tl, In, Cd, Sn, in Zeeman Atomic absorption devices for assaying natural, drinking, waste and technical water as well as air, soil, food products and biological samples. The first steps are made for optimization of Ge, Ga, P, S, …
Monopolium production from photon fusion at the Large Hadron Collider
2008
6 pages, 6 figures.-- PACS nrs.: 14.80.Hv; 95.30.Cq; 98.70.-f; 98.80.-k.-- Printed version published Aug 2009.-- ArXiv pre-print available at: http://arxiv.org/abs/0809.0272
X-ray irradiation influence on prototype Er3+-optical fibers: confocal luminescence study
2010
International audience; The integration of rare-earth doped optical fibers as part of fiber-based systems in space implies the development of waveguides tolerant to the radiation levels associated with the space missions. We report the spatial distribution, the photoluminescence (PL) properties of color centers and the related changes induced by X-rays radiation at different doses (50, 500 and 1000 krad) for two different prototypes of Er-doped optical fibers. Each sample (in the version pristine, X-irradiated and H2 loaded prior to radiation exposure) was characterized by confocal microscopy luminescence (CML) measurements in Visible range with Visible (488 nm) or UV (325 nm) laser light e…
Spectroscopic studies of the origin of the radiation-induced degradation in phosphorous-doped optical fiber and preforms
2010
In this paper, we study the radiation-induced point defects related to the phosphorus element that is commonly used to improve the optical properties of silica-based glasses but is responsible of a dramatic increase in their radiation sensitivity. To this aim, the influence of x-ray irradiation on prototype phosphorus-doped canonical fibers and their related preforms was investigated by in situ radiation induced attenuation (RIA), optical absorption, and electron spin resonance (ESR) spectroscopy. The RIA spectra in the (1.5-5 eV) range, can be explained by the presence of at least three absorption bands induced by radiation exposure. Additionally the X-dose dependence of such bands was stu…
Effect of irradiation temperature on the radiation induced attenuation of Ge-doped fibers
2016
International audience; The UV-visible radiation induced attenuation (RIA) was studied in Ge-doped optical fibers, during X-ray (10 keV) irradiations at different temperatures. By comparing the spectra recorded in dissimilarly irradiated samples we evidenced the impact of the irradiation temperature. In details, we highlighted that, from a certain dose, increasing the temperature the RIA decreases for wavelengths lower than 470 nm, whereas at higher wavelengths the RIA depends only on the dose. Such findings suggest that it is possible to distinguish the irradiation temperature by comparing the signal at two different wavelengths. From the microscopic point of view, it appears that the RIA …