İbrahim Han

Determination of K shell absorption jump factors and jump ratios of 3d transition metals by measuring K shell fluorescence parameters.

Energy dispersive X-ray fluorescence technique (EDXRF) has been employed for measuring K-shell absorption jump factors and jump ratios for Ti, Cr, Fe, Co, Ni and Cu elements. The jump factors and jump ratios for these elements were determined by measuring K shell fluorescence parameters such as the Kα X-ray production cross-sections, K shell fluorescence yields, Kβ-to-Kα X-rays intensity ratios, total atomic absorption cross sections and mass attenuation coefficients. The measurements were performed using a Cd-109 radioactive point source and an Si(Li) detector in direct excitation and transmission experimental geometry. The measured values for jump factors and jump ratios were compared with theoretically calculated and the ones available in the literature.

Valence-electron configuration of Ti and Ni in TixNi1−x alloys from Kβ-to-Kα X-ray intensity ratio studies

Kbeta-to-Kalpha X-ray intensity ratios of Ti and Ni have been measured in pure metals and in alloys of Ti(x)Ni(1-x) (x=0.7, 0.6, 0.5, 0.4 and 0.3) following excitation by 22.69 keV X-rays from a 10 mCi (109)Cd radioactive point source. The valence-electron configurations of these metals were determined by corporation of measured Kbeta-to-Kalpha X-ray intensity ratios with the results of multiconfiguration Dirac-Fock calculation for various valence-electron configurations. Valence-electron configurations of 3d-transition metals in alloys indicate significant differences with respect to the pure metals. Our analysis indicates that these differences arise from delocalization and/or charge transfer phenomena in alloys. Namely, the observed change of the valence-electron configurations of metals in alloys can be explained with the transfer of 3d electrons from one element to the other element and/or the rearrangement of electrons between 3d and 4s, 4p states of individual metal atoms.

Effect of external magnetic field on valence-electron structures of Fe and Ni in Invar, Permalloy and the other Fe–Ni alloys by using Kβ-to-Kα X-ray intensity ratios

The effect of external magnetic field on the valence-electron structures of Fe and Ni in various Fe-Ni alloy compositions was investigated by using X-ray fluorescence spectroscopy. Firstly, Kβ-to-Kα X-ray intensity ratios of Fe and Ni in Invar (Fe0.64Ni0.36), Permalloy (Fe0.20Ni0.80) and FexNi1-x (x=0, 0.40, 0.52, 0.55, 0.61, and 1) alloys were measured without any magnetic field and under 0.5 and 1T external magnetic fields, separately. Later, the valence-electron structures of Fe and Ni in both pure form and alloys were obtained by comparison of measured X-ray intensity ratios with the results of multi-configurations Dirac-Fock (MCDF) calculations. The results obtained for valence-electron structures of Fe and Ni in various Fe-Ni alloys were evaluated in terms of magnetic field effect, delocalization and/or charge transfer phenomena. The results have shown that valence electron structure of Fe and Ni in Fe-Ni alloys are dependent on both external magnetic field and concentration of alloy elements.

Determination of K shell XRF parameters and K to L shell vacancy transfer probabilities of ferromagnetic 3d transition metals

In this study, K shell X-ray fluorescence cross-sections (σKα, σKβ and σK), K shell fluorescence yields (ωK) and K to L shell vacancy transfer probabilities (ηKL) of ferromagnetic 3d transition metals (Fe, Co, Ni) were investigated to understand how the relationship between ferromagnetism and these values changes with atomic number by using energy dispersive X-ray fluorescence (EDXRF) technique. The all obtained experimental and theoretical results were comparatively given as a function of the atomic number. It was clearly observed that all of the investigated parameters depend on the atomic number and the ferromagnetism state of the atom.

Determination of Chemical Effect on the Kβ1/Kα, Kβ2/Kα, Kβ2/Kβ1 and Kβ/Kα X-Ray Intensity Ratios of 4d Transition Metals

ABSTRACT It is clear that detailed studies performed under identical experimental conditions are desirable to determine the effect of the chemical environment on the value of intensity ratios. To better understand this effect, we conducted measurements on Kβ1/Kα, Kβ2/Kα, Kβ2/Kβ1 and Kβ/Kα x-ray intensity ratios. The Kα and Kβ1,2 emission spectra for compounds of 4d transition metals Y, Zr, Nb, and Mo were measured using a Si(Li) solid-state detector. The samples were excited by 22.69 keV x-rays emitted from a 109Cd radioisotopes source. The experimental results for pure elements are compared with the other experimental and theoretical values.

Investigation of alloying effects on XRF parameters of 3d transition metals in Permendur49, Kovar and Ti 50 Co 50 alloys

Abstract The alloying effects on X-ray fluorescence (XRF) parameters such as K shell fluorescence cross-sections (σKα, σKβ and σK), K shell average fluorescence yields (ωK) and K to L shell vacancy transfer probabilities (ηKL) of V, Ti, Fe, Co and Ni 3d transition metals in Permendur49 (Fe49Co49V2), Kovar (Fe54Ni29Co17) and Ti50Co50 alloys have been carried out by X-ray fluorescence studies. K X-ray intensity ratios of these 3d transition metals in both pure form and present alloys have been measured following excitation by 22.69 keV X-rays from a 10 mCi 109Cd radioactive point source. The characteristic K-X-ray spectra from samples were detected by a high-resolution Si(Li) solid-state detector. The investigated fluorescence parameters of present 3d transition elements in alloys indicate significant differences with respect to the pure metals. Consequently, the observed change of the investigated fluorescence parameters can be attributed to the delocalization and charge transfer phenomena between the 3d elements in alloys.

Alloying effect on K shell X-ray fluorescence cross-sections and yields in Ti-Ni based shape memory alloys

Abstract K shell X-ray fluorescence cross-sections (σKα, σKβ and σK), and K shell fluorescence yields (ωK) of Ti, Ni both in pure metals and in different alloy compositions (TixNi1-x; x = 0.3, 0.4, 0.5, 0.6, 0.7) were measured by using energy dispersive X-ray fluorescence (EDXRF) technique. The samples were excited by 22.69 keV X-rays from a 10 mCi Cd-109 radioactive point source and K X rays emitted by samples were counted by a high resolution Si(Li) solid-state detector coupled to a 4 K multichannel analyzer (MCA). The alloying effects on the X-ray fluorescence (XRF) parameters of Ti-Ni shape memory alloys (SMAs) were investigated. It is clearly observed that alloying effect causes to change in K shell XRF parameter values in Ti-Ni based SMAs for different compositions of x. Also, the present investigation makes it possible to perform reliable interpretation of experimental σKα, σKβ and ωK values for Ti and Ni in SMAs and can also provide quantitative information about the changes of K shell X-ray fluorescence cross sections and fluorescence yields of these metals with alloy composition.

Comparison of Martian meteorites with earth composition: Study of effective atomic numbers in the energy range 1 keV-100 GeV

Effective atomic (Zeff) and electron numbers (Neff) for 24 Martian meteorites have been determined in the energy range from 1 keV to 100 GeV and also for sixteen significant energies of commonly used radioactive sources. The values of Zeff and Neff for all sample were obtained from the DirectZeff program. The obtained results for Martian meteorites have been compared with the results for Earth composition and similarities or differences also evaluated.

Angular Distribution of Fluorescent L X-Rays and Compton-Scattering Photons

ABSTRACT The angular distribution of fluorescent L X-rays and Compton-scattering photons was investigated by measuring differential cross sections for high–atomic-number elements. The measurements were taken simultaneously for L X-ray and Compton-scattering photons using Am-241 radioisotope as photon sources and a Si(Li) detector in various emission angles. The measurements confirm well-known angular dependency of the Compton-scattering differential cross section. L X-ray angular distribution measurements were carried out for the Ll, Lα, Lβ, and Lγ lines. It was observed from measured differential cross sections that Ll and Lα X-ray differential cross sections for the L3 substate depended on the emission angle, meaning that Ll and Lα X-rays had an anisotropic spatial distribution. On the other hand, the Lβ and Lγ X-rays do not show any significant anisotropy.