Elastic and compton scattering cross sections in the atomic region 12 ⩽ Z ⩽ 82

doi:10.1016/0969-8043(95)00270-7

Applied Radiation and Isotopes

Volume 47, Issue 2, February 1996, Pages 219-227

https://doi.org/10.1016/0969-8043(95)00270-7 Get rights and content

Abstract

Coherent and Compton scattering cross sections for the elements Mg, Al, Mn, Ni, Cu, Y, Mod, Pd, Ag, Cd, In, Sn, Sb, Au and Pb have been measured at 32.06 keV (Ba Kα) and 33.29 keV (La Kα) x-ray energies. Measurements have been performed using an x-ray tube with a secondary excitor system as the excitation source instead of radioisotopes. In order to improve the efficiency of the detection system the excitation source detector and the sample assembly were placed in a vacuum chamber and a pressure of 10⁻² mbar was maintained throughout the measurements. The present system reduced the scattering and background effects considerably and improved the monochromaticity. Experimental coherent scattering cross sections are compared with the normalised integrated coherent scattering cross sections. Experimental results are higher around the edges indicating the oscillatory nature of coherent intensity, resonance behaviour and fine structure effects. Experimental incoherent scattering cross sections are higher than the theoretical estimates for low medium Z elements and lower for heavy elements. The latter is due to the effect of electron binding at low photon energies for heavy elements.

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The evaluated experimental data are presented for 14 known nuclides of mass 89 (Ge, As, Se, Br, Kr, Rb, Sr, Y, Zr, Nb, Mo, Tc, Ru, Rh). New data on high–spin excitations are available for ⁸⁹Kr, ⁸⁹Rb, ⁸⁹Sr, ⁸⁹Tc and ⁸⁹Ru, including a superdeformed structure in ⁸⁹Tc. Fluorescence studies in ⁸⁹Y have revealed a large number of new levels in 7–11 MeV range. New two–neutron transfer data are available for ⁸⁹Zr. New direct and precise measurement of atomic masses of ⁸⁹Se, ⁸⁹Br, 89^Kr, ⁸⁹Rb, ⁸⁹Mo and ⁸⁹Tc have greatly improved the Q value landscape in this mass region. This work supersedes previous A=89 evaluation published in 1998Si31, and also the older ones 1989Si20, 1975Ko21, and M.W. Johns et al., Nuclear Data Tables A 8, 373 (1970).
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Differential incoherent scattering cross sections of $59.54 keV$ photons were measured for Ti, Fe and Ni elements at scattering angles 40–135° employing a reflection geometry set up and a graded shielding arrangement. The measurements were performed using a point source of Am-241 radioisotope as photon source and a Si(Li) detector. Thin targets have been used to minimize the contribution of multiple scattered photons to the inelastic scattered peak. The product of the intensity of incident photons and geometrical factors was eliminated using the K X-ray yields from same elements. The comparison of the measured cross sections with Klein–Nishina theory shows electron-binding effects becoming significantly large at small scattering angles. Incoherent scattering functions S(x,Z), corresponding to momentum transfer values 1.644– $4.442 A ̊^{−1}$ were extracted from the measured cross sections and were compared with theoretical predictions. The results are compared with the non-relativistic Hartree–Fock values.
Incoherent scattering of 59.54 keV γ-rays at small momentum transfers
2001, Radiation Physics and Chemistry
Whole atom differential incoherent scattering cross sections for 59.54 keV γ-rays were measured for a number of elements in the region 29⩽Z⩽82 at scattering angles 90, 60, 45 and 30° employing a reflection geometry set up and a graded shielding arrangement. A 6 cm³ HPGe detector was used to detect the scattered γ-rays. All the 49 cross sections reported in this paper constitute the first experimental measurement and serve to fill the existing gaps in the cross-section data. The comparison of the measured cross sections with Klein–Nishina theory shows electron binding effects becoming significantly large at small scattering angles and for high Z elements. Incoherent scattering functions S(x, Z), corresponding to momentum transfer values 3.395, 2.4, 1.84 and 1.242 Å⁻¹ were extracted from the measured cross sections and were compared with the theoretical predictions. The non-relativistic Hartree–Fock theory is found to be comparatively better than the Thomas–Fermi model. At small momentum transfer values and for high Z elements experimental values deviate more from Hartree–Fock theory also suggesting the need for a more rigorous second-order S-matrix calculations.
Simple method to measure the differential coherent scattering cross-sections of elements
2000, Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms
The coherent scattering of 59.54 keV γ-rays by Zr, Nb and Mo scatterers has been studied of scattering angles from 40° to 135° by using a Si(Li) detector. A new method was developed for the accurate measurement of cross-section. This method involves measurement of differential coherent cross-section in terms of measured by the detector at each scattering angle the K X-ray counting rates from the target of the element under study. The experimental results have been compared with the different formalisms of form factor theory.
Nuclear data sheets for A = 89
1998, Nuclear Data Sheets
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A new method to estimate elastic scattering cross sections in the X-ray region and the associated anomalous dispersion
1998, Applied Radiation and Isotopes
Using nearly monoenergetic unpolarised Kα radiation, we have measured the elastic scattering cross sections for Pt, Au and Pb in the energy region 5.41 ≤ E ≤ 9.23 keV. The experimental results for Pt, Au and Pb are new. A new X-ray scattering system was assembled using an X-ray tube and secondary targets. In order to improve the peak-to-background ratio and the efficiency of the detection system, particularly in the low-energy region, excitation source, sample and detector assembly were placed in a vacuum chamber at a pressure of 10⁻² mbar. The present system helped considerably in reducing the scattering and background effects, and in removing the interference of Ar K X-rays which fall in the investigated regions. A new method was developed to estimate the degree of monochromaticity, geometrical effects of the measuring system, solid angle correction and some considerations which are necessary in experiments using X-ray tube with secondary target arrangement. Experimental elastic scattering cross sections are compared with theoretical estimates, a combination of relativistic modified form factors with angle independent anomalous scattering factors (RMF + ASFs) and recent theoretical estimates based on the multipole expansion of the second order S-matrix approach. Deviations are observed around the edges (high energy side) indicating the importance of the dispersion correction terms. The present experimental results are useful taking into account that the available calculated values describe the free atom and deviations for a solid have to be expected. This is due to the difference of the electronic structure of the solid in comparison to the free atom as a base for theoretical estimations. However, the comparison of experimental results with theoretical estimates indicates the importance of numerical calculations based on the multipole expansion of the second order S-matrix approach and high energy limit values (RMF + ASFs).

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Radioactivity and radiation measurementElastic and compton scattering cross sections in the atomic region 12 ⩽ Z ⩽ 82

Abstract

Nucl. Instr. Meths.

At. Data. Nucl. Data. Tables

Phys. Rep.

Phys. Rep.

Nucl. Instr. Meths.

Nucl. Instr. Meths.

Elastic scattering of 81 keV γ-rays

Phys. Rev.

XCOM: photon cross sections on a personal computer

NBSIR 87-3597

Compton scattering of photons from bound electrons: full relativistic independent particle approximation calculations

Phys. Rev.

X-rays in Theory and Experiment

X-ray scattering factors computed from numerical Hartree-Fock wave-functions

Acta Crystallo

Atomic scattering for x-rays

Encyclopedia of Physics

A large angle coherent/Compton scattering method for measurements in vitro of trabecular bone mineral concentration

Med. Phys.

X-ray attenuation coefficients from 10 keV to 100 MeV

Evaluation of geometrical contributions to the spread of the Compton scatter energy distribution

Phys. Rev.

Contours of constant scattering angle

Phys. Rev. Lett.

Radioactivity and radiation measurement
Elastic and compton scattering cross sections in the atomic region 12 ⩽ Z ⩽ 82