Contribution of bremsstrahlung of free electrons to formation of the background component for NaK X-ray fluorescence

Zirconium-doped MgxZn1−xO (Zr-doped MZO) mixed-oxide films were investigated, and the temperature sensitivity of their electric and optical properties was characterized. Zr-doped MZO films were deposited through radio-frequency magnetron sputtering using a 4-inch ZnO/MgO/ZrO2 (75/20/5 wt%) target. Hall measurement, X-ray diffraction (XRD), transmittance, and X-ray photoelectron spectroscopy (XPS) data were obtained. The lowest sheet resistance, highest mobility, and highest concentration were 1.30 × 103 Ω/sq, 4.46 cm2/Vs, and 7.28 × 1019 cm−3, respectively. The XRD spectra of the as-grown and annealed Zr-doped MZO films contained MgxZn1−xO(002) and ZrO2(200) coupled with Mg(OH)2(101) at 34.49°, 34.88°, and 38.017°, respectively. The intensity of the XRD peak near 34.88° decreased with temperature because the films that segregated Zr4+ from ZrO2(200) increased. The absorption edges of the films were at approximately 348 nm under 80% transmittance because of the Mg content. XPS revealed that the amount of Zr4+ increased with the annealing temperature. Zr is a potentially promising double donor, providing up to two extra free electrons per ion when used in place of Zn2+.

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Multiply ionized carbon plasmas with index of refraction greater than one

Laser and Particle Beams ◽

10.1017/s0263034607070085 ◽

2007 ◽

Vol 25 (1) ◽

pp. 47-51 ◽

Cited By ~ 11

Author(s):

J. FILEVICH ◽

J. GRAVA ◽

M. PURVIS ◽

M.C. MARCONI ◽

J.J. ROCCA ◽

...

Keyword(s):

Laser Interferometry ◽

General Assumption ◽

Capillary Discharge ◽

Index Of Refraction ◽

Carbon Ions ◽

Free Electrons ◽

X Ray ◽

Computer Calculations ◽

Approximation Analysis ◽

Bound Electrons

For decades the analysis of interferometry have relied on the approximation that the index of refraction in plasmas is due solely to the free electrons. This general assumption makes the index of refraction always less than one. However, recent soft x-ray laser interferometry experiments with Aluminum plasmas at wavelengths of 14.7 nm and 13.9 nm have shown fringes that bend the opposite direction than would be expected when using that approximation. Analysis of the data demonstrated that this effect is due to bound electrons that contribute significantly to the index of refraction of multiply ionized plasmas, and that this should be encountered in other plasmas at different wavelengths. Recent studies of Silver and Tin plasmas using a 46.9 nm probe beam generated by a Ne-like Ar capillary discharge soft-ray laser identified plasmas with an index of refraction greater than one, as was predicted by computer calculations. In this paper we present new interferometric results obtained with Carbon plasmas at 46.9 nm probe wavelength that clearly show plasma regions with an index of refraction greater than one. Computations suggest that in this case the phenomenon is due to the dominant contribution of bound electrons from doubly ionized carbon ions to the index of refraction. The results reaffirm that bound electrons can strongly influence the index of refraction of numerous plasmas over a broad range of soft x-ray wavelengths.

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Influence of Free Charge on the Lattice Parameters of GaN and Other Semiconductors

MRS Proceedings ◽

10.1557/proc-468-311 ◽

1997 ◽

Vol 468 ◽

Cited By ~ 4

Author(s):

M. Leszczyński ◽

J. Bąk-Misiuk ◽

J. Domagała ◽

T. Suski

Keyword(s):

Lattice Parameters ◽

Deformation Potential ◽

Free Charge ◽

Bulk Crystals ◽

Free Electrons ◽

X Ray ◽

Mg Doping ◽

Conduction Bands ◽

Vegard’S Law ◽

Homoepitaxial Layers

ABSTRACTLattice parameters of semiconductors depend on the concentration of free electrons via the deformation potentials of the occupied minima of the conduction bands. In the presented work we examined the lattice parameters of variously doped GaN samples (epitaxial layers on sapphire and on SiC, bulk crystals grown at high hydrostatic pressure and homoepitaxial layers). The following dopants were used: Si, Mg and O. The measurements were performed using high resolution X-ray diffractometry. The results indicate that free electrons expand the lattice what confirms a negative value of the deformation potential of the Γ minimum of the conduction band. However, for Mg-doping (acceptor) we observed the lattice expansion as well. This violates the Vegard's law, as Mg ions are smaller than Ga ions.

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Cosmic background X-rays produced by intergalactic innerbremsstrahlung

Symposium - International Astronomical Union ◽

10.1017/s0074180900004538 ◽

1970 ◽

Vol 37 ◽

pp. 372-373

Author(s):

Satio Hayakawa

Keyword(s):

Absolute Intensity ◽

Proton Spectrum ◽

X Rays ◽

Background Component ◽

Critical Test ◽

X Ray ◽

Cosmic Background ◽

Distant Galaxies ◽

Inverse Compton ◽

The Absolute

It has been found difficult to explain both the absolute intensity and energy spectrum of the background component of cosmic X-rays in terms of a superposition of X-ray sources in distant galaxies [1] and of the inverse Compton collisions of metagalactic electrons with microwave photons [2]. Although the absolute intensity could be obtained by choosing suitable values of parameters which are not well known as yet, the gradual bending of the X-ray spectrum around 30 keV provides a critical test of theories. In this respect innerbremsstrahlung of intergalactic protons colliding with electrons is a candidate of background X-rays, since the X-ray spectrum is closely related to the proton spectrum and the latter usually bends in the non-relativistic region.

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The advent of X-ray free electron lasers

Photoniques ◽

10.1051/photon/202111022 ◽

2021 ◽

pp. 22-26

Author(s):

Marie-Emmanuelle Couprie

Keyword(s):

Free Electron ◽

Peak Power ◽

Short Pulse ◽

Far Infrared ◽

Gain Medium ◽

High Peak Power ◽

X Rays ◽

Free Electron Lasers ◽

Free Electrons ◽

X Ray

Free Electron Lasers (FEL) use free electrons in the periodic permanent magnetic field of an undulator as a gain medium. They extend from far infrared to X-rays, they are easily tunable and provide a high peak power. The advent of tunable intense (few mJ) short pulse (down to the attosecond regime) FELs with record multi GW peak power in the X-ray domain enables to explore new scientific areas. These unprecedent X-ray sources come along with versatile performance.

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Electro-Thermal and Semiconductivity Behaviour of Natural Sintered Complex Carbonate Ore for Thermo-Technological Applications

Journal of Geochemistry ◽

10.1155/2014/451782 ◽

2014 ◽

Vol 2014 ◽

pp. 1-10 ◽

Cited By ~ 1

Author(s):

Loutfy H. Madkour

Keyword(s):

Energy Gap ◽

Sintering Temperature ◽

Thermal Analyses ◽

Charge Carriers ◽

Degree Of Crystallinity ◽

Power Coefficient ◽

Free Electrons ◽

Dc Voltage ◽

X Ray ◽

Main Charge

The polymetal (Zn, Pb, Fe, Ca, Mg, Cd, Ba, Ni, Ti, and SiO2) complex Umm-Gheig carbonate ore is subjected to sintering treatment at 573, 773, 973 and 1273 K respectively for four hours. Chemical, spectral, X-ray and differential thermal analyses are applied for the native ore as well as for the samples preheated and sintered. The current versus applied DC voltage (I–V) characteristics, bulk density (Db), percent shrinkage (%S), activation energy (Ea) and energy gap (Eg) are established for the sintered ore. The electrical conductivity σ, thermal conductivity (K) and thermoelectric power coefficient α have been investigated as a function of applied temperature for the sintered ore materials. The electrical conduction is mainly achieved by free electrons near or in conduction band or n-type. As the sintering temperature (Ts) increases the conduction of the ore is also increased due to the recombination process taking place between the electrons and holes. Electrons hopping between Fe2+ and Fe3+ are the main charge carriers. The formation of Fe3O4 at high sintering temperature acts as an active mineralizer, thus inducing an increased degree of crystallinity and a more ordered crystal structure is produced.

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Influence of Substrate Temperature on the Al and Zr Co-Doped ZnO Thin Films Prepared by RF Magnetron Sputtering

Materials Science Forum ◽

10.4028/www.scientific.net/msf.814.601 ◽

2015 ◽

Vol 814 ◽

pp. 601-606 ◽

Cited By ~ 1

Author(s):

Fei Huan ◽

Jin Feng Leng ◽

Zhi Chao Meng ◽

Bin Sun ◽

Wen Shuang He

Keyword(s):

Thin Films ◽

Magnetron Sputtering ◽

Substrate Temperature ◽

Rf Magnetron Sputtering ◽

Radio Frequency Magnetron Sputtering ◽

X Ray Diffraction ◽

Free Electrons ◽

X Ray ◽

Influence Of Substrate ◽

Co Doped

ZnO doped Al2O3and ZrO2(ZAZO) thin films were deposited by the radio frequency magnetron sputtering on substrate temperature with 100°C, 150°C, 200°C, 250°C and 300°C. The surface morphology and electrical properties of the films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and four-probe tester. The results showed that the substrate temperature obviously influenced the grain size of ZAZO films. The ZnO thin film had the largest crystallization orientation for the (002) peak and the smallest FWHM value at substrate temperature of 250°C. As the temperature increasing, the resistance of films gradually decreased till reaching a minimum at 250°C and then rised. Due to the increasing of Al and Zr concentrations into ZnO lattice, the Al ions created an abundance number of free electrons in the ZnO lattice, and in turn, the electrical conductivity increased. In addition, the improvement of film in the crystalline state results in the film resistivity decreases.

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