The X-ray fluorescence cross-section for bromide and iodide compounds

The K_α and K_β X-ray fluorescence cross-sections for the bromide and the iodide compounds were measured by a high-resolution Si(Li) X-ray detector. The vacancies were produced by heavily filtered ²⁴¹Am gamma rays. We found that K_α and K_β X-ray fluorescence cross-sections are changed by chemical effect for different Br and I compounds. Experimental results were compared with the calculated values of Br and I elements. Received 15 May 2001 and Received in final form 8 July 2001     

Determination of probabilities of vacancy transfer from K to L shell using K X-ray intensity ratios

K to L shell vacancy transfer probabilities (η_KL) for 26 elements in the atomic region 23≤Z≤57 were determined by measuring the I_Kβ/I_Kα intensity ratios. The targets were irradiated with γ-photons at 59.543 keV from ²⁴¹Am annular source. The K X-rays from different targets were detected with a high resolution Si(Li) detector. Theoretical values were calculated using the radiative and radiationless transition rates of these elements. The measured values of η_KL are compared with the theoretical values and data of others. The measurement vacancy transfer probabilities are least-square fitted to third-order polynomials to obtain analytical relations that represent these probabilities as a function of atomic number. The measured values of η_KL for V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se and Br are being reported here for the first time.     

Measurement of K X-ray intensity ratios in Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn employing carbon and nitrogen projectiles – VTT method

A method is suggested to effect the self absorption correction in a different way to estimate the K X-ray intensity ratios particularly when heavy ions are used as projectiles. Employing this method, the K_β/K_α intensity ratios are measured in some 3d shell elements by using Carbon and Nitrogen ions as exciting agents. The K_β/K_α intensity ratios thus obtained in the present work are compared with the intensity ratios due to some previous authors and also with Scofield theoretical values. Received 14 August 2000 and Received in final form 3 January 2001     

The effect of the chemical environment on theKβ/Kα X-ray intensity ratio

Summary Chemical effects on theKβ/Kα X-ray intensity ratios were investigated for different constitutions of Ti, V, Fe, Se, Br, Zr and Ce by a Ge(Li) X-ray detector. The vacancies were produced by heavily filtered²⁴¹Am gamma-rays. It is found that theKβ/Kα X-ray intensity ratios measured with compounds deviated up to 12% from the corresponding values of the pure elements (Ti, V, Fe) are larger than for the others (Se, Br, Zr and Ce).     

Measurement of the K α to L α and K β to L β intensity ratios of seven elements in the atomic number range 52≤ Z ≤62 using photoionization at 59.5 keV1

The Kα to Lα and Kβ to Lβ intensity ratios of seven elements have been measured following photoionization at 59.5 keV by using a Si (Li) detector (FWHM=155 eV at 5.96 keV). The intensity ratios were determined by measuring K and L x-rays emitted from a standard target of a given element. The theoretical values of the Kα to Lα and Kβ to Lβ intensity ratios were calculated using theoretically tabulated values of shell/subshell photoionization cross sections, fluorescence yields, Coster-Kronig transition probabilities, and radiative decay rates for ηKLi≠ and ηKLi=0. The measured values are in good agreement with theoretical results. From Optika i Spektroskopiya, Vol. 97, No. 2, 2004, pp. 186–189. Original English Text Copyright ? 2004 by A. Kü?ük?nder, S?ğüt, E. Kü?ük?nder, Büyükkasap. This article was submitted by the authors in English.     

Chemical effects on the K<Subscript>β</Subscript>/K<Subscript>α</Subscript> X-ray intensity ratios of Mn,Ni and Cu complexes

Chemical effects on the K_β/K_α X-ray intensity ratios for some Mn, Ni, and Cu complexes of a new schiff-base with salen N₂H₂ type were investigated. The samples were excited by 59.543 keV γ-rays from a ²⁴¹Am annular radioactive source. K X-rays emitted by samples were counted by a Si(Li) detector with resolution 157 eV at 5.9 keV. We observed the chemical effect on the K_β/K_α X-ray intensity ratios for Mn, Ni and Cu complexes. The experimental results showed that the K_β/K_α X-ray intensity ratios for compounds with complexes are generally larger than those with salt form. The experimental values have been compared with the other experimental and the theoretically calculated values of pure elements. The results are in very good agreement with the others.     

The effect of an external magnetic field on the <Emphasis Type="Italic">L</Emphasis><Subscript>3</Subscript> subshell fluorescence yields and level widths for Ta,W, Tl,Th and U at 59.54 keV photons

The effect of an external magnetic field on the L₃ subshell fluorescence yields (ω₃ ) and level widths ($\Gamma_{L_3}$) for paramagnetic Ta, W, Tl, Th and U have been investigated using the 59.54 keV incident photon energy in the external magnetic field of intensities ±0.60 T. L₃ X-ray fluorescence cross sections ($\sigma_{L_3}^{X}$) have been measured for the same elements. The measured ω ₃, $\Gamma_{L_3} $ and $ \sigma_{L_3}^X$ values for B = 0 are in good agreement with the theoretical values. It was observed that the values of $\sigma_{L_3}^X$ and ω₃ with the applied magnitude of the magnetic field in both directions show a decreasing trend for paramagnetic Ta, W, Tl, Th and U. Furthermore, in the presence of an external magnetic field, the values of $\Gamma_{L_3}$ show an increasing trend for the same elements. The results show that the atomic parameters such as spectral linewidth, radiation rates, photoionization cross section and fluorescence yield can change when the irradiation is conducted in a magnetic field.     

K X-ray fluorescence cross-sections for some light elements excited by keV photons

K and K X-ray fluorescence cross-sections have been experimentally determined for the elements Cu, Se, Y, and Mo at excitation energies 23.62, 24.68, 36.82, 43.95, 48.60, and 50.20keV using an X-ray tube with a secondary exciter system as the excitation source. The X-ray tube with a secondary target arrangement was used to obtain high intensity with high degree of monochromatization. Experimental values were compared with the theoretical values using tabulated I ratios based on Hartree-Fock and Hartree-Slater theories calculated by Scofield. The experimental values for all the elements at various excitation energies are in good agreement with the theoretical values.     

Measurements of K-shell ionization cross sections of35Br,37Rb,39Y using low energy protons

K-shell ionization cross section measurements are reported for₃₅Br,₃₇Rb and₃₉Y targets caused by protons over 300–400 keV energy range in 20 keV increment. The K-shell ionization cross sections (σ _k ^l ) at different energies were deduced from the K_α and K_β X-ray production cross sections which were obtained from X-ray yields of the K_α and K_β transitions. The experimental values are compared with the calculated values of ECPSSR theory and empirical reference cross sections. The resultant K-shell ionization cross sections are found to be in reasonable agreement with the ECPSSR theory. The K_α/K_β intensity ratios are also presented and compared with other experimental values and also with the theoretical one-hole values given by Scofield.     

Measurement of K β K /α values using proton beamvalues using proton beam

The Measurement of K _β K _/α intensity ratios are measured in some 3d shell elements by using a 2 MeV proton beam along with a high resolution Si(Li) detector. The present Measurement of K _β K _/α intensity ratios are in good agreement with Scofield modified theoretical values, thus supporting the basic assumptions in that theory. From the present Measurement of K _β K _/α intensity ratios, it is evident that due to chemical effects, the experimental Measurement of K _β K _/α intensity ratios will be increased while they will be decreased due to the presence of simultaneous M-shell vacancies which are produced due to proton excitation.     

Average fluorescence yields of M4,5 subshells for thorium and uranium

M_4,5 subshells average fluorescence yields (ϖ_M4,5) have been determined for thorium and uranium using M_4,5 X-ray production cross-sections at 5.96 keV incident photon energy. The measurements have been performed using a ⁵⁵Fe annular source and an Ultra-LEGe detector. The present values are compared with calculated theoretical values and theoretical average M shell fluorescence yields (ϖ_M). Fair agreement (to within 22–27%) is typically obtained between present average fluorescence yields (ϖ_M4,5) and calculated theoretical values.     

Empirical,Semi-Empirical and Experimental Determination of K X-Ray Fluorescence Parameters of Some Elements in the Atomic Range 21 ≤ Z ≤ 30

In this study, the semi-empirical and empirical calculations of K X-ray intensity ratios, K-shell fluorescence yields, and vacancy transfer probabilities have been performed for 3d transition elements. Also, σ_Kα, σ_Kβ production cross-sections, K_β/K_α intensity ratios, ω_K fluorescence yields, and η_KL vacancy transfer probabilities of 3d transition elements have been measured. The samples were excited by 59.5 keV γ-rays from a ²⁴¹Am annular radioactive source. K X-rays emitted by samples were counted by an Ultra-LEGe detector with a resolution of 150 eV at 5.9 keV.     

Variation of Kβ/ Kα X-ray intensity ratio and lineshape with the effects of external magnetic field and chemical combination

In this work, the effects caused by different chemical combination and external magnetic field in several copper and zinc compounds (Cu, CuBr, Cu₂O, CuI, CuCl, Cu₂Te, Cu₅Si, CuSO₄, CuSeO₄.5H₂O, CuCl₂, Cu(NO₃)₂, CuS, CuSe, CuF₂, CuF2.3H₂O, CuBr₂, Cu(ClO₄)₂.6H₂O, Zn, ZnSO₄.5H2O, Zn(C₂H₃O₂)₂, ZnF₂, Zn(NO₃)₂.6H₂O, ZnO, ZnS, ZnSe, ZnTe and ZnF₂.4H₂O) were studied using a Si(Li) detector. The samples were excited by 22.69 keV X-rays from ¹⁰⁹Cd point radioactive source of strength 10 mCi in the external magnetic field of intensities 0.6 T and 1.2 T. The shift, asymmetry, FWHM and Kβ/Kα intensity ratio values were determined. For B = 0, the present experimental results were compared with the experimental and theoretical data in literature. The results have shown that the atomic parameters such as energy shifts, asymmetry indices, FWHM and Kβ/Kα intensity ratios can change when irradiation is conducted in a magnetic field.     

L X-ray energy shifts and intensity ratios in tantalum with C and N ions — multiple vacancies in M, N and O shells

The energy shifts and intensity ratios of different L X-ray components in tantalum element due to 10 MeV carbon and 12 MeV nitrogen ions are estimated. From the observed energy shifts, the possible number of simultaneous vacancies in M shell are estimated. A comparison of L _α /L _β2.15, L _β1/L _γ1 and L _γ2.3/L _γ4.4 with the ratios due to Scofield theoretical transition rates indicate that the number of multiple vacancies in N shell are higher than the vacancies in M and O shell. Employing Larkin’s statistical scaling procedure, the number of possible multiple vacancies in N and O shells are estimated quantitatively.     

Chemical effects on the L-shell X-ray fluorescence parameters of Ta and W compounds

The L shell X-ray production cross-sections, the intensity ratios_, and the average fluorescence yields of pure Ta, W and their compounds have been analysed. The targets were irradiated with γ-photons at 59.5 keV from a ²⁴¹Am annular source and detected using an Ultra-LEGe detector with resolution of 150 eV at 5.9 keV. The experimental results were compared with the other theoretical and experimental results. The obtained results were interpreted according to the chemical effect and influence of removing electrons from the shells above the L shell.     

Measurement of total M shell photoionization cross sections for Au,Pb, Th and U in the energy region 6–12 keV

The total M shell relative photoionization cross-sections for Au, Pb, Th and U have been measured in the energy region 6–12 keV. External conversion K X-rays of suitable elements has been employed as incident photons to photo ionize the total M shell of elements under investigation. The method provides relative cross-sections therefore does not make use of theoretically calculated average M shell fluorescence yields which involve uncertainties of the order of 20%. No evidence of deviation from calculated values of cross-sections have been observed within experimental errors for all incident photon energies.     

Chemical Effect on L X-ray Intensity Ratios of Mercury,Lead, and Bismuth

INTRODUCTION

The information regarding the experimental values of K and L X-ray intensity ratios are important due to its wide use in many areas of basic and applied science and non-destructive elemental analysis of materials using the X-ray fluorescence technique. Chemical effects on K and L X-ray intensity ratios are not very well known, but they are an interesting subject. Some studies [1–4] addressing chemical effects on the K_β/K_α intensity ratios have been made. We investigated chemical effects [5–7] and alloying effects [8] on the K_β/K_α intensity ratios, and measured K_β/K_α intensity ratios following radioactive decay and photoionisation [9]. But there are few studies addressing chemical effects on the L X-rays intensity ratios. Iihara et a1.[10] examined chemical effects on chromium L X-rays.     

Residual impurity effects on the magnetic ordering in α-Mn observed by hyperfine interaction

We report on the lattice location of indium in and the magnetic ordering of manganese in its α- and β-phases, as seen by perturbed angular correlation. Quadrupole interaction spectra show that indium prefers to replace Mn atoms of type I in α-Mn, but replaces type II atoms in the β-Mn structure. The interaction strength equalseQV _zz /h=3.6 (6) MHz in α-Mn and 172.3 (3) MHz with ν=0.13 (1) in β-Mn. No magnetic ordering down to 4.2 K was observed in β-Mn, while belowT _N =95 K in the α-Mn phase, a magnetic hyperfine interaction appears indicating two distinct magnetic probe environments. The hyperfine field, when measured atT=4.2 K, equals for 70% of the probes 6.33 (1) T, while the remaining fraction senses a 3.10 (4) T field. The magnitudes of the hyperfine fields are essentially unaffected by a variety of conditions in the sample preparation. The ordering temperature, on the contrary, turns out to be rather sensitive to residual impurities especially any oxygen contamination.     

The use of parallel and monochromatic beams for determining the composition of pseudobinary alloys by X-ray fluorescence

A simple X-ray fluorescence method using nearly parallel and monochromatic beams is analyzed and discussed in connection with the determination of the alloy fraction in pseudobinary A_1−x B _x C solid solutions. Applications to optoelectronic materials are considered. The reliability of the method has been analyzed and discussed for both bulk and thin film samples. Errors due to small angular divergence in the accepted beam are seen to be neglibile. Deviations from a symmetrical alignment of the sample can strongly influence the measured fluorescence intensity. The experimental analysis of this effect can be used for a perfect symmetrical orientation of thick samples. The measurement of the fluorescence intensity as a function of the glancing angle can give both thickness and composition in solid-solution thin-film samples. The contributions of the fluorescence radiation excited by the characteristic X-ray lines of atoms within the substrate is shown to be important in thin epitaxial layers. An approximate formula for calculating these contributions is given and discussed in the light of experimental results. Bulk crystals and thin-film samples, vapourphase grown Cd_1−x Zn _x S solid solutions, have been used for experiments in which the ZnK _α radiation excited by a MoK _α primary beam was measured.     

Experimental investigation of angular dependence of photon induced L-shell X-ray emission intensity

The angular dependence of emission intensity of L shell X-rays induced by 59.57 keV photons in Pb and U is investigated by measuring the normalized intensities of the resolved L X-ray peaks at different angles varying from 40° to 120°. It is observed that while L _l and L_α X-ray peaks (originating fromJ = 3/2 state) show some anisotropic angular distribution, the emission of L_β and L_γ X-ray peaks is isotropic. The present results contradict the calculations of Co-oper and Zare (1969) that after photoionization of inner shell, the vacancy state has equal population of magnetic substates and the subsequent X-ray emission is isotropic but confirm the predictions of Fluggeet al (1972) that the atomic inner shell vacancies produced after photoionization are aligned and the x-ray emission from the filling of vacancies in state withJ ⩾ 3/2 is anisotropic.