Absolute cross-sections from X– coincidence measurements (original) (raw)
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Development of a coincidence system for the measurement of X-ray emission atomic parameters
2013
Preliminary results obtained in experiments carried out with an x-ray spectrometer built at the Instituto de Física for Atomic Physics and environmental sciences studies are presented. The experiments are based on a coincidence method for signals produced by LEGe and Si(Li) detectors. The x-ray fluorescence yields (Z Li ) and Coster-Kronig transition probabilities (f ij ) for elements with 55 Z 60 are among the quantities of interest. The method is based on the simultaneous detection of K x-rays with the LEGe detector and the L x-rays with the Si(Li) detector. The primary radiation source is an x-ray tube with Rh anode. The system was tested with the coincidence of the L x-rays from Ce with its K line, demonstrating the feasibility of the experiments.
Contribution due to excitation by scattered photons in measurements of L x-ray cross-sections
X-ray Spectrometry, 1989
The relative contribution to the production of target L x-rays by the scattered and K x-ray parts of excitation spectra from different secondary excitors in annular source geometry is estimated. In contrast to the observations of N. Singh et ul., who made similar measurements using triaxial geometry, we found only a small contribution to the production of L x-rays by the scattered part of the excitation spectrum in comparison with that by the K x-ray part. We crosschecked the observations by measuring L x-ray cross-sections for five elements, Pr, Nd, Sm, Tb and Yb, at 22.6 keV by two methods: (i) using a 109Cd radioisotope source in the direct excitation mode and (ii) using a secondary excitor of Ag with a 241Am radioisotope source as the primary excitor, in annular source geometry. The results obtained by the two methods are found to be in good agreement.
X-Ray Spectrometry, 2005
L x-ray fluorescence cross-sections for elements with 45 ≤ Z ≤ 50 were measured at 7 keV using synchrotron radiation photoionization. The experimental set-up provided a linearly polarized monoenergetic photon beam producing a low background and improving the signal-to-noise ratio. The data obtained for the L lines, Ll, La, Lb I , Lb II , Lg I and Lg II , were grouped considering the transition scheme, the energies of the emission lines and the detector resolution. Results for the experimental cross-sections obtained were compared with theoretical values using two different data tables. In general, it was found that the experimental fluorescence cross-sections are slightly higher (7-10%) than the theoretically calculated data and in some cases these differences are up to 40%.
A B S T R A C T L l , L α , L β and Lγ 1 X-ray fluorescence cross-sections for 74 W have been measured at excitation energies of 12, 14, 15 and 16.5 keV using synchrotron radiations. A Peltier cooled Vortex solid state detector (SII Nano Technology, USA) with an energy resolution of 138 eV at 5.96 keV X-rays was employed for analysis. The experimental results were compared with the theoretical estimates of and and also compared with existing experimental results (Barrea and Bonzi, 2001b) of L XRF cross sections at the excitation energy of 12 and 14 keV. Present results were found to be closer to the Puri's data in comparison to existing experimental results. For the first time, to our knowledge, L XRF cross section for 74 W at energies 15 and 16.5 keV are also being reported here.
Total fusion cross sections for 18, 17, 16O + 27Al at energies near the Coulomb barrier
Nuclear Physics A, 1977
Aoetr~ct : Total fusion cross sections bavo been measured for r°" l' "'sO-F ."Al systems at bombarding energies 272 MeV. The evaporation residues wero detected is the angular raa®e 4°-25°(Iab) using a dE-E counter telescope. Barrier radii extracted from total fusion and elastic scattering corsa sections aro found to increase with the projectile mass . The effect of the yraat levels on the isotopic yields in the evaporation cascade is iaveatigated . NUCLEAR REACTIONS~'Al('s0, X), ( l'O, X), ( 1s0, X), E -27-42 MeV; measured complote ürsioa a(E). sv~(rs0~is0) . ("O, rv 0,) fe0,'b), E = 21-40 MeV. Measured c(E, 8) ; deduced effectivo fusion radii.
Spectrochimica Acta Part B: Atomic Spectroscopy, 2001
Experimental determinations of L X-ray fluorescence cross-sections for elements with 72 F Z F 75 at 12, 13 and 14 keV were carried out with synchrotron radiation. The experimental set-up provided a linearly polarized monoenergetic photon beam producing a very low background, which improved the signal-to-noise ratio and reduced the experimental uncertainties. Results of the experimental cross-sections obtained for the L lines were grouped considering the transitions scheme, the energies of the emission lines and the detector's resolution. The data obtained were compared with theoretical ones using two different data tables. A very good agreement was found Ž Ž . between our experimental values and the theoretical values calculated using Puri's data X-Ray Spectrom. 22 1993 . 358᎐361 . ᮊ .ar R.A. Barrea . 0584-8547r01r$ -see front matter ᮊ 2001 Elsevier Science B.V. All right reserved. Ž . PII: S 0 5 8 4 -8 5 4 7 0 1 0 0 3 0 6 -8 ( ) R.A. Barrea, E.V. Bonzi r Spectrochimica Acta Part B: Atomic Spectroscopy 56 2001 2429᎐2437 2430
L X-ray fluorescence cross sections experimentally determined for elements with 45<Z<50 at 9keV
Applied Radiation and Isotopes, 2012
Experimental determination of L fluorescence cross-sections for elements with 45 o Zo 50 have been determined at 9 keV 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, La, Lb I , Lb II , Lg I and Lg II 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