Characterization of the Carancas�CPuno meteorite by energy dispersive X-ray fluorescence, X-ray diffractometry and transmission M?ssbauer spectroscopy

We report the results of the study of a meteorite that impacted an inhabited zone on 15 September 2007 in the neighborhood of the town of Carancas, Puno Region, about 1,300 km south of Lima. The analysis carried out by energy dispersive X-ray fluorescence, X-ray diffractometry and transmission Mössbauer spectroscopy (at room temperature and at 4.2 K), reveal the presence in the meteorite sample of magnetic sites assigned to taenite (Fe,Ni) and troilite (Fe,S) phases, and of two paramagnetic doublets assigned to Fe^2?+?, one associated with olivine and the other to pyroxene. In accord with these results, this meteorite is classified as a type IV chondrite meteorite.     

L X-ray fluorescence cross sections and yields for mediumZ elements in the energy region 5.47 ≤E ≤ 9.36 keV

TotalL X-ray fluorescence cross sections have been measured in the atomic region 39 Z 51 excited by 5.47, 6.47, 7.04, 7.57, 8.14, 8.74 and 9.36 keV photons. Experimental cross sections are compared with the theoretical estimates of Chen et al. based on relativistic Dirac-Hartree-Slater theory. Good agreement is observed between experimental results and theoretical estimates in the studied atomic and energy region. Experimental fluorescence yields have been evaluated using the experimental fluorescence cross sections and theoretical subshell photoionization cross sections. Fluorescence yields are fitted by least squares to fifth-order polynomials inZ of the form _n a _n z ⁿ and compared with theoretical and earlier fitted values. The deviation of the average fluorescence yield in the atomic region 46Z 51 with new theoretical estimates of , calculated using the ECPSSR (Energy loss Coulomb deflection Perturbed Stationary State Relativistic effects) theory of Brandt and Lapicki and the fitted values clearly indicate the weak dependence of the average fluorescence yield on the initial vacancy distribution.     

Mineralogy of the clay fraction of soils from the moray cusco archaeological site: a study by energy dispersive X-ray fluorescence, X-ray diffractometry and M?ssbauer spectroscopy

The purpose of this work is to report the advances in the elemental and structural characterization of the clay fraction of soils from the terraces of the Moray Archaeological site, located 38 km north of the city of Cusco, Cusco Region. One sample was collected from each of the twelve terraces of this site and its clay fraction was separated by sedimentation. Previously the pH of the raw samples was measured resulting that all of the samples were from alkaline to strongly alkaline. Energy dispersive X-ray fluorescence (EDXRF) was used for the elemental characterization, and X-ray diffractometry (XRD) and transmission Mössbauer spectroscopy (TMS), using the ?? 14.4 keV nuclear resonance transition in ⁵⁷Fe, were used for the structural characterization of the clays and clay minerals present in each sample. The EDXRF analyses of all the samples show the presence of relatively high concentrations of sulfur in some of the samples and relatively high concentrations of calcium in all of the samples, which may be related to the high alkalinity of the samples. By XRD it is observed the presence of quartz, calcite, gypsum, cronstedtite, 2:1 phyllosilicates, and iron oxides. The mineralogical analysis of Fe by TMS shows that it is present in the form of hematite and occupying Fe^2?+? and Fe^3?+? sites in phyllosilicates, cronstedtite, and other minerals not yet identified.     

M1 transition energy and rate in the ground configuration of Ag-like ions with 62 ≤ Z ≤ 94

Systematic calculations and assessments are performed for the magnetic dipole(M1)transition energies and rates between the ²F^o_5/2,7/2 levels in the ground configuration 4d104f along the Ag-like isoelectronic sequence with 62≤Z≤94 based on the second-order many-body perturbation theory implemented in the Flexible Atomic Code.The electron correlations,Breit interaction and quantum electrodynamics effects are taken into account in the present calculations.The accuracy and reliability of our results are evaluated through comprehensive comparisons with available measurements and other theoretical results.For transition energies,our results are in good agreement with the recent experimental data obtained from the electron beam ion traps within 0.18%.The maximum discrepancy between our results and those obtained with the large-scale multiconfiguration Dirac–Hartee–Fock calculations by Grumer et al.[Phys.Rev.A 89062501(2014)]is less than 0.13%along the isoelectronic sequence.Furthermore,the corresponding M1 transition rates are also reported.The present results can be used as the benchmark and useful for spectra simulation and diagnostics of astrophysical and fusion plasmas.     

Measurement of Lα/Lℓ, Lα/Lβ and Lα/Lγ X-ray intensity ratios for elements in the atomic range 57⩽Z⩽92 using radioisotope X-ray fluorescence

Lα/Lℓ, Lα/Lβ and Lα/Lγ intensity ratios have been measured for some elements with atomic range 57⩽Z⩽92 by using characteristic L X-rays from targets excited by 59.54 keV photons from a filtered radioisotope ²⁴¹Am point source. Theoretical values of the Lα/Lℓ, Lα/Lβ and Lα/Lγ intensity ratios were calculated using theoretically tabulated values of subshell photoionization cross-sections, fluorescence yields, fractional X-ray emission rates, Coster–Kronig transition probabilities. Experimental results have been compared with the theoretical values and other available experimental results. Good agreement was observed between experimental results, other available experimental results and theoretically calculated values.