X-ray Fluorescence Cross-sections Research Articles

M sub-shell X-ray fluorescence cross-section measurements in high Z elements with X-ray tube photon source

X-ray tube has been used for selective M sub-shell excitations in a single reflection set-up for Pt, Au, Pb, Th and U required for M sub-shell fluorescence cross-sections measurements. Weighted photon energy and total intensity of the incident flux between E M5 edge and tube anode voltage were evaluated following a specific procedure. Comparison of measured cross-sections with the calculated ones from existing DHS/DF model based theoretical data on atomic parameters lend support to the present findings.

Determination of L X-ray fluorescence parameters for Ho, Lu, W, Hg and Bi

In this work, L X-ray fluorescence cross sections, L sub-shell fluorescence yields and level widths and radiative vacancy transfer probabilities of L sub-shells to Mi, Ni and Oi sub-shells were measured for the elements Ho, Lu, W, Hg and Bi. Energy dispersive X-ray fluorescence (EDXRF) technique was used to measure L X-ray photons. To obtain related parameters, we used 59.54keV gamma photons of 241Am radioactive point source. Emitted L X-ray photons from targets were collected by means of a Si(Li) detector with resolution of 180eV at 5.9keV. The present results are generally in a good agreement with theoretical calculations and the other results obtained in the literature, within their range considering experimental uncertainty.

Measurement of Photon-Induced <i>L</i> X-Ray Fluorescence Cross Sections for Ho and Yb in the 16.04 - 24.68 keV Energy Range

Lα, Lβ, and Lγ X-ray fluorescence cross sections for Ho and Yb have been measured at various incident photon energies in the energy range 16.04 ≤ E ≤ 24.68 keV. The measurements have been done using an X-ray tube with a secondary-excitor system of Zr, Nb, Mo, Cd, and In. The experimental values of the cross-sections were determined by measuring the absolute yield of L subshell X-rays emitted from a standard target of a given energy. Theoretical tabulated values of subshell photoionization cross-sections, fluorescence yields, Coster-Kronig transition probabilities and radioactive decay rates have been used to calculate the theoretical values of the cross-sections. The experimental results of the cross-sections at various excitation energies have been compared with theoretically calculated values. Fairly good agreement is obtained between the present experimental results and the calculated values.

Energy dependence of photon-induced Kα and Kβ x-ray production cross-sections for some elements with 38≤Z≤51 in the energy range 20–50 keV

The energy dependence of photon-induced Kα and Kβ x-ray production (or x-ray fluorescence) cross-sections for Sr, Y, Mo, Ru, Pd, Ag, In and Sb elements has been studied in the energy range of 20–50keV using Energy Dispersive X-Ray Fluorescence (EDXRF) Spectrometry. The photon energy dependence of K x-ray production cross-sections was measured with secondary excitation method. A radioisotope point source of 241Am was employed to excite the K x-rays of secondary exciter elements. The L x-ray yields from Th and U were measured to determine IoG (the intensity of exciter K x-rays falling on primary target). The measurements have been made by observing the x-ray emissions with the help of HPGe detector coupled with a multichannel analyzer. The areas of the Kα and Kβ spectral peaks, as well as the net peak areas, have been determined by a fitting process. The measured Kα and Kβ x-ray production cross-sections have been compared with calculated theoretical values in this energy regime. The present experimental results for all the elements were in general agreement with the theoretical values calculated using photoionization cross-sections, fractional rates (based on Hartree–Slater potentials) and fluorescence yields.

L X-ray fluorescence cross sections experimentally determined for elements with 45

Experimental determination of L fluorescence cross-sections for elements with 45<Z<50 have been determined at 9keV using Synchrotron radiation. This work is part of an investigation we did at low energies in the same group of elements. The individual L X-ray photons, Ll, Lα, LβI, LβII, LγΙ and LγΙΙ produced in the target were measured using a Si(Li) detector. The experimental set-up provided a low background by using linearly polarized monoenergetic photon beam, improving the signal-to-noise ratio. The experimental cross sections obtained in this work were compared with data calculated using coefficients from Scofield (1973), Krause et al., (1978), Krause (1979) and Scofield and Puri et al. (1993, 1995)

Variation of the L X-ray fluorescence cross-sections, intensity ratios and fluorescence yields of Sm and Eu in halogen compounds

The chemical effect on the L i ( i=ι, α, β, β 1, β 2, γ) X-ray fluorescence cross-sections, the L X-ray intensity ratios and the average L shell fluorescence yields of Sm and Eu binary compounds with halogen (F, Cl and Br) were investigated. The samples were excited by 59.543 keV photons emitted from an Am-241 radioisotope source. X-rays emitted from the samples were counted by means of a Si(Li) detector, which has a resolution 155 eV at 5.9 keV. The experimental values were compared with the calculated theoretical values

Measurement of L X-ray fluorescence cross-sections for elements with 45 ⩽ Z ⩽ 50 using synchrotron radiation at 8 keV

The L shell fluorescence cross-sections of the elements in range 45 ⩽ Z ⩽ 50 have been determined at 8 keV using Synchrotron radiation. The individual L X-ray photons, Ll, Lα, Lβ I, Lβ II, Lγ I and Lγ II produced in the target were measured with high resolution Si( Li) detector. The experimental set-up provided a low background by using linearly polarized monoenergetic photon beam, improving the signal-to-noise ratio. The experimental cross-sections obtained in this work were compared with available experimental data from Scofield [1,2] Krause [3,4] and Scofield and Puri et al. [5,6]. These experimental values closely agree with the theoretical values calculated using Scofield and Krause data, except for the case of Lγ, where values measured of this work are slighter higher.

Disparity in formulations used for fluorescent X-ray intensity measurements

The paper presents a problem in computations of X-ray fluorescence cross-sections, shell/sub-shell fluorescence yields, Coster–Kronig yields, vacancy alignment, etc. from X-ray fluorescence (XRF) studies. While using barn/atom as a unit for cross-sections if the atomic masses are not considered it causes a discrepancy in the measured cross-section, yield and alignment values. Most of the earlier publications are being quoted where such an oversight has occurred and discrepancy is evident.

Measurement of L subshell fluorescence cross sections and intensity ratios of heavy elements at 22.6 keV

The L X-ray fluorescence cross sections ( σ L1, σ Lα, σ Lη , σ Lβ, σ Lβ6 , σ Lβ2,4,15 , σ Lβ1,3 , σ Lγ , σ Lγ1 , σ Lγ2,3,6,8 , σ Lγ4,4′ and σ Lγ5 ) and I Lα / I Li ( i= l, η, β 6, β 2,4,1,5, β 1,3, γ, γ 1, γ 2,3,6,8, γ 4,4 ′ and γ 5 intensity ratios for some elements in the atomic range 66≤ Z≤92 have been measured at 22.6 keV photon energy emitted from a 109Cd radioactive point source. The L X-rays emitted by samples have been counted by a Si(Li) detector. The L X-ray fluorescence cross sections and intensity ratios have also been calculated theoretically by using atomic parameters. The measurement results have been compared with available data and the theoretical values. Within experimental deviations, our data are in good agreement with the available data and the theoretical values.

Parameterization and generation of photon-induced K cross-sections

Theoretical K-shell photoionization and K X-ray fluorescence (K XRF) cross sections have been fitted empirically in polynomials of photon energy E and atomic number Z. This has been used to develop a computer code KCSPIF to generate K-shell photo-ionization and K XRF cross-sections for any element in the range 5 ≤Z≤95 and for photon energies, above K-edge–1500 keV, when only the atomic number and photon energy are supplied as the input.

Measurement of Lα, Lβ and Total L X-ray fluorescence cross-sections for some elements with 40≤ Z≤53

Lα, Lβ and total L X-ray fluorescence (XRF) cross-sections have been measured for the nine elements (Zr, Nb, Mo, Ag, Cd, In, Sn, Sb and I) using photon energy 5.96 keV. In these the elements, Lα and Lβ spectra were derived from the measured L-shell spectra by fitting process. Experimental results of Lα, Lβ and total L X-ray fluorescence cross-sections have been compared with theoretical results. The experimental results of L XRF cross-section are found to be in agreement with the theoretical values.

F-64 L Shell X-ray Fluorescence Cross-Sections for Elements with 33 ≤ Z ≤ 50

Accurate experimental data regarding the X-ray fluorescence (XRF) cross sections and fluorescence yields are important in basic studies of nuclear and atomic processes leading to the emission of X-ray and Auger electrons. The data is also required for many practical applications like elemental analysis by x-ray emission technique, dosimetric computation for medical physics and irradiation processes [1]. A systematic study of the Li (i =1-3) subshell x-ray fluorescence cross sections at the 5.89 keV photon energy has been undertaken for the elements in the atomic region 33  Z  50. The measurements have been performed under vacuum ~10 -2 torr using energy-dispersive spectrometer involving an LEGe (FWHM 150 eV at 5.895 keV) detector. The cross sections for the possible resolved L x-ray components were deduced and compared with those evaluated using the most reliable theoretical values of Li (i = 1, 2, 3) subshell photoionization cross sections, fluorescence yields, x-ray emission rates and Coster-Kronig transition probabilities [2]. For the L, L and L1,5 groups of x rays, the measured cross sections for all the elements are in agreement with theoretical cross sections. The measured L2,3 cross sections in the atomic region 39  Z  46 are in general agreement within ~10% except for 39Y, where the difference ~25% was observed. The comparison provides the insight regarding the cutoff energy of the L1-L2M4,5 and L1-L3M4,5 CK transitions at Z~39, and L1-L3M4,5 and L2-L3M4,5 CK transitions at Z ~50 as predicted by the RDHS model [2].

Variation of [formula omitted] X-ray fluorescence cross-sections of Cu, Y and Ba in Y Ba 2Cu 3O 7−δ superconductor

K X-ray fluorescence cross-sections of Cu, Y and Ba elements were measured in CuO, Y 2O 3, BaCO 3 compounds and Y Ba 2Cu 3O 7−δ superconductor samples (nonreacted agent, calcined and sintered states). A superconductor sample of Y Ba 2Cu 3O 7−δ was prepared by using a solid-state reaction technique. The samples were excited by gamma rays of energy 59.5 keV from a 241Am radioisotope source. The Cu, Y and Ba K X-ray intensities counted with a Si(Li) detector were measured in different solid-state conditions. The obtained values of K X-ray fluorescence cross-section were compared with the theoretical values of pure Cu, Y and Ba elements. We found that the K X-ray fluorescence cross-section of Cu, Y and Ba in Y Ba 2Cu 3O 7−δ sample is changed in different solid-state conditions, depending on the mixture (nonreacted agent), calcined and sintered states.

Measurements of K X-ray fluorescence cross sections of Fe, Co, and Ni in an external magnetic field

The effects of the external magnetic field has been investigated on the K XRF cross sections of Fe, Co, Ni, and some of their compounds by using an energy dispersive X-ray fluorescence spectrometer. The samples were irradiated by using the γ-rays of 59.537 keV emitted from an 241Am radioisotope source of 100 mCi. The samples were prepared from pure foil of Fe, Co, Ni, and some of their compounds. The external magnetic fields have been applied two opposite directions and the magnitude of the external magnetic field has been fixed at 0.400 T and −0.400 T. The measured K XRF cross sections have been compared with the calculated theoretical data and interpolated values of Puri et al. Our experimental results show that the K XRF cross sections have been affected by the external magnetic field.

L-subshell vacancy decay processes for elements with52≤Z≤57following ionization using MnKαx rays

The ${L}_{i}$- $(i=1--3)$ subshell x-ray spectra for the $_{52}\text{T}\text{e}$, $_{53}\text{I}$, $_{55}\text{C}\text{s}$, $_{56}\text{B}\text{a}$, and $_{57}\text{L}\text{a}$ elements excited by Mn $K\ensuremath{\alpha}$ (${E}_{K{\ensuremath{\alpha}}_{2}}=5.888\text{ }\text{keV}$ and ${E}_{K{\ensuremath{\alpha}}_{1}}=5.899\text{ }\text{keV}$) x rays have been investigated using the $^{55}\text{F}\text{e}$ radioisotope in conjunction with a Cr absorber. A low-energy Ge detector was used to measure the $L$ x rays at an emission angle $\ensuremath{\psi}=126\ifmmode^\circ\else\textdegree\fi{}$, where the second-order Legendre polynomial term ${P}_{2}$ $(\text{cos}\text{ }\ensuremath{\psi})$ associated with the angular distribution is annulled. In the case of the $_{56}\text{B}\text{a}$ and $_{57}\text{L}\text{a}$ elements, alignment of the ${L}_{3}$-subshell vacancy states was investigated through angular distribution measurements of the emitted ${L}_{3}$-subshell x rays. The $L{\ensuremath{\alpha}}_{1,2}$ and $L{\ensuremath{\beta}}_{2,15}$ x-ray groups are observed to be nearly isotropic, while the data for the pure $Ll$ $({L}_{3}\text{\ensuremath{-}}{M}_{1})$ x-ray emission are indicative of a small anisotropic trend, though within experimental error. The integral x-ray fluorescence cross sections are deduced and interpreted in terms of ${L}_{i}$-subshell photoionization cross sections, fluorescence and Coster-Kronig yields, and x-ray emission rates. The ${L}_{2}$-subshell x-ray cross sections for $_{57}\text{L}\text{a}$ measured using targets of lanthanum (III) fluoride and dilanthanum (III) trioxide are found to be unusually higher. The enhancement is observed due to the contribution of the ${L}_{2}$-subshell radiative resonant Raman scattering (RRS) of Mn $K\ensuremath{\alpha}$ x rays having energy around the ${L}_{2}$-subshell binding energy of $_{57}\text{L}\text{a}$ in these compounds. Also, the observed enhancement of the ${L}_{3}$-subshell x-ray cross sections in $_{57}\text{L}\text{a}$ is suggestive of intrashell vacancy transfer via ${L}_{2}\text{\ensuremath{-}}{L}_{3}$ Coster-Kronig RRS transitions. The ${L}_{2}$-subshell total RRS cross sections in $_{57}\text{L}\text{a}$ have been deduced from the present measured attenuation coefficients for Mn $K\ensuremath{\alpha}$ x rays in ${\text{La}}_{2}{\text{O}}_{3}$ and ${\text{LaF}}_{3}$. The ${L}_{2}$-subshell radiative and total RRS cross sections in $_{57}\text{L}\text{a}$ using ${\text{LaF}}_{3}$ are higher by $\ensuremath{\sim}30%$ than those using ${\text{La}}_{2}{\text{O}}_{3}$. The contribution of processes predicted in the framework of Mozouchi's four-band model involving inner subshells along with the valence and conduction bands of these wide-band-gap insulator compounds is likely to account for the observed results. The ${L}_{2}$-subshell radiative and ${L}_{2}\text{\ensuremath{-}}{L}_{3}$ Coster-Kronig yields and the ratio of the ${L}_{2}\text{\ensuremath{-}}{M}_{4}$ and ${L}_{2}\text{\ensuremath{-}}{N}_{4}$ radiative RRS intensities in both La compounds are found to be same and are consistent with values from photoexcited vacancy decay. The ${L}_{2}$-subshell radiative RRS was also observed to be isotropic.

Angular variations of K and L X-ray fluorescence cross sections for some lanthanides

Kα, Kβ, Lα, and Lβ X-ray fluorescence cross sections for lanthanides in the atomic range 62 ≤ Z ≤ 68 (Sm, Eu, Gd Tb, Dy, Ho, and Er) were simultaneously measured by 59.54 keV incident photon energy at five angles ranging from 120° to 160°. The measurements were performed using an Am-241 radioisotope as the photon source and a Si(Li) detector. The Lα X-ray fluorescence cross section (σLα) was found to decrease with increasing emission angle and showed an anisotropic distribution of Lα X-rays. Kα, Kβ, and Lβ X-ray fluorescence cross sections (σKα, σKβ, and σLβ) were observed to be angle-independent and showed an isotropic distribution of Kα, Kβ, and Lβ X-rays. The Kα and Kβ X-rays originate from filling of the K shell (J = 1/2) vacancies, Lβ X-rays from filling of the L1 and L2 (J = 1/2) subshell vacancies, and Lα X-rays from filling of the L3 subshell (J = 3/2) vacancy. The fluorescent X-rays originating from the vacancy states with J = 1/2 are isotropic and unpolarized, but fluorescent X-rays originating from the vacancy states with J &gt; 1/2 are anisotropic and polarized. Thus, the atomic inner shells vacancy states with J &gt; 1/2 are aligned whereas vacancy states with J = 1/2 are not aligned. Lα fluorescence X-rays have an anisotropic distribution, while Kα, Kβ, and Lβ fluorescence X-rays have isotropic distribution. Furthermore, the IKβ/IKα, ILα/IKα}, ILβ/IKα, and ILβ/ILα intensity ratios for the elements under investigation were determined. The experimental cross sections and intensity ratios for Kα, Kβ, Lα, and Lβ fluorescence X-rays were also determined, and these experimental values were compared with our calculated theoretical values.PACS Nos.: 32.30.Rj, 32.80.Cy

Measurement of L X-ray fluorescence cross sections and relative intensities for some elements in the atomic range 78 ≤ Z ≤ 92

The L X-ray fluorescence cross sections ( σ Ll, σ Lα, σ Lη, σ Lβ, σ Lβ6, σ Lβ2, 4, σ Lβ1, 3, σ Lβ9,10, σ Lγ, σ Lγ1, σ Lγ2,3, σ Lγ4 and σ Lγ5) and relative intensities ( I Lα, I Ll, I Lη, I Lβ, I Lβ6, I Lβ2,4, I Lβ1,3, I Lβ9,10, I Lγ, I Lγ1, I Lγ2,3, I Lγ4 and I Lγ5) for some elements in the atomic range 78 ≤ Z ≤ 92 have been measured at 59.54 keV photons energies from an Am-241 point source. The L X-rays emitted by samples have been counted by a Si(Li) detector. The L X-ray fluorescence cross sections and relative intensities have been also calculated theoretically by using atomic parameters. The measured values have been compared with the theoretical values.

L ι, L α, L β and L γ X-ray fluorescence cross-sections of heavy elements for the exciting photons energy 38.18, 43.95, 50.21 and 59.5 keV

The cross-sections for the production of L ι , L α , L β and L γ X-ray fluorescence (XRF) in Er, Ta, W, Au, Hg, Tl, Pb and Bi by photons with energies in the range 38–59.5 keV have been measured, using a standard doublereflection experimental set-up. Measurements have been performed using an annular 241 Am primary source and X-ray emitting secondary-exciter system. Experimental cross-sections have been compared with the theoretically calculated values of L X-ray cross-sections and fairly good agreement is observed between the experimental and theoretical values.

The effect of an external magnetic field on the L subshell X-ray fluorescence cross sections and L subshell fluorescence yields in elements 73 ≤ Z ≤ 92 by 59.54 keV photons

L i ( i = 1, 2 and 3) X-ray fluorescence cross sections for Ta, W, Au, Hg, Tl, Pb, Bi, Th and U have been measured using the 59.54 keV incident photons energy in the external magnetic field of intensity +0.60 T. The values of L i subshell fluorescence yields ( w 1 , w 2 and w 3 ) have been measured for the same elements using the previously measured cross section values and the theoretical L i subshell photoionisation cross sections, Coster–Kronig transition probabilities and emission rates. It is observed that the measured L i subshell X-ray fluorescence cross section and L i subshell fluorescence yield values for B = 0 are in good agreement with the theoretical ones evaluated using L i subshell fluorescence yield and L i subshell photoionization cross section. Furthermore, 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-shell X-ray fluorescence cross-sections and intensity ratios for some pure metals at 59.5 and 123.6 keV

K-shell X-ray fluorescence cross-sections for some pure metals such as Cr, Fe, Co, Cu, Zn, Ga, Se, Y, Mo, Cd, In, Sn, Te, Ba, Ta, W and Bi have been theoretically and experimentally determined. The Cr, Fe, Co, Cu, Zn, Ga, Se, Y, Mo, Cd, In, Sn, Te and Ba metals were excited by 59.5keV γ-ray from 50mCi 241Am radioactive source and the Ta, W and Bi targets were excited by 123.6keV γ-ray from 25mCi 57Co radioactive source. The characteristic K X-rays emitted by samples were detected by using a super Si(Li) detector having a resolution of 150eV at 5.9keV. In addition, the IKβ/IKα intensity ratios for these metals were studied. The obtained experimental values of the K-shell X-ray fluorescence cross-sections and the IKβ/IKα intensity ratios have been compared with theoretical values. The measured values were in good agreement with theoretical values.