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Submitted on 1 Jan 1979
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RAYLEIGH AND COMPTON SCATTERING CROSS SECTIONS OF X-RAYS BY OXYGEN IONS
A. Kupliauskiené, Z. Kupliauskis
To cite this version:
A. Kupliauskiené, Z. Kupliauskis. RAYLEIGH AND COMPTON SCATTERING CROSS SECTIONS OF X-RAYS BY OXYGEN IONS. Journal de Physique Colloques, 1979, 40 (C7), pp.C7-853-C7-854.
�10.1051/jphyscol:19797412�. �jpa-00219413�
JOURNAL DE PHYSIQUE CoZZoque C7, s u p p t d m e n t a u n07, Tome 40, J u i Z Z e t 1979, page C7- 853
RAYLnGH AND COMPTON XATTEFUNG CROSS SECTIOUS OF X-RAYS BY OXYGEN IONS
A.V. ~ u ~ i i a w k i e n e and Z.J. ~ u ~ l i a u s k i s ' .
t I n s t i t u t e of P h y s i c s of t h e Academy o f S e i e m e s of t h e L i t h u a n i a n SSR, Vf h i m , U.S.S.R.
V. Kapsukas V i Z i u s S t a t e U n i v e r s t i t y , V i Z n i u s , U.S. S . R.
The methods based on the photon scattering are widely used in plasma diagnostic [I)
.
The X-rays and gamma rays attenuation and energy absorption coeffi- cients are proportional to the total pho- ton interaction cross section per atom, i.e. to the sum of the cross sections of all the elementary scattering and absorp- tion processes. The atomic cross sections for X-rays absorption at energies above 1 keV can be written as the sum of all partial cross sections for the photoelec- tric effect, for Rayleigh and Compton scattering. X-rays and gamma rays scatte- ring cross sections for neutral atoms have been summarized by Hubbell et a1 [2,3].
The ions of different degree of ionization exist in plasma. It is there- fore important to consider the change in the Rayleigh and Compton scattering cross sections when the neutral atoms are re- placed by the corresponding ions.In this paper, we report the diffe- rential and total Rayleigh and Compton scattering cross sections of X-rays by the atom and iona of oxygenelhe variation of the Rayleigh scattering cross sections with the excitatiog and ionization of the neutral oxygen atom has been investigated in
14).
The differential Rayleigh scattering
cross sections at low incident-photon energies decrease as the degree of ioni- zation of the atom increases at all angles. As the incident-photon energy in-
creases, scattering cross sections at large angles do not depend on the degree of ionization whereas the scattering by outer-shell electrons is insignificant.
The differential scattering cross sections decrease with increasing scattering angle and reach a minimum at scattering angles of 9/2
-
2 V ' 3 . The reduction in the cross sections at small angles is. more rapid for higher energies and the growth of the cross sections sections is more ra- pid at lower values of X-rays energy.As the degree of ionization increases the differential Compton scattering cross sections decrease at all scattering angles and for all energies. The cross sections grow with the increasing scattering angle for small photon energies. The reduction of the cross sections is obtained in the region q . 2 of the scattering angle when the X-rays energies exceed 10 keV. The differential Compton scattering cross sec- tions of X-rays increase from zero at the zero scattering angle and reach the maxi- mum at the scattering angle equal to ST.
Table 1 lists the Rayleigh scattering cross sections, and Table 2 lists the
Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:19797412
Table 1 The Rayleigh scattering cross sections of X-rays (bardatom) E(keV) 0 0 [2] O+ 02+
1 40.047 39.89 31.186 23.018 2 33.926 33.55 27.582 20.596 3 26.997 26.61 23.118 17.501 4. 21 0067 20.79 18.883 14.474 6 13,325 13.21 12,627 9.863 8 9.209 9.145 8.936 7.091 10 6.852 6.805 6.730 5.421 15 .3.967 3.942 3.982 3.295 20 2.636 2.623 2.693 2.256 E(keV) 03+ 04+ 05+ 06+
1 16.109 10.374 5.889 2.654 2 14.714 , 9.643 5.618 2.635 3 12.854 8.638 5.229 2.602 4 10.937 7.560 4.788 2.558 6 7.799 5.688 3.947 2.440 8 5.778 4.398 3.287 2.289 10 4.516 3.556 2.804 2.119 15 2.858 2.391 2.021 1.676 20 2.006 1.738 1.510 1.288 Compton scattering cross sections of X-rays by the atom and ions of oxygen.
From the tables it is evident that our data are in good agreement with 123 for the neutral oxygen atom. The results listed in the tables show clearly that the Rayleigh scattering cross sections de- crease while those of Compton increase for the neutral atom and al1,the ions in- vestigated as the photon energy increases.
The Rayleigh and Compton scattering cross sections of X-rays are very dependent on the degree of ionization. The reduction in the cross sections with the increasing degree of ionization of the atom is more
Table 2
The Compton scattering cross sections of X-rays (barn/atom) E(keV) 0 0 (21 O+ 02+
1 0.211 0.226 0.130 0.113 2 0.721 0.756 0.494 0.408 3 1,319 1.352 0.943 0.786 4 1.867 1.886 1.379 1.162 6 2.672 2.665 2.069 1,746 8 3.152 3.139 2.514 2.112 10 3.452 3.439 2,800 2,349 15 3.873 3.864 3.208 2.707 20 4.098 4.092 3.438 2.914 E(keV;) 03+ 04+ 05+ 06+
1 0.086 0.066 0.032 0.003 2 0.310 0.239 0.117 0.013 3 0.602 0.462 0,231 0.029 4 0.895 0.680 0.348 0.050 6 1.355 1.010 0.543 0.106 8 1.645 1,211 0.682 0.175 10 1.837 1,348 0.791 0.252 15 2.143 1.592 1.012 0.447 20 2.336 1.764 1.181 0.611 significant at small energies whereas the contribution of outer-shell electrons is more important.
References
1. Properties of low energy plasma and its diagnostic (in Russian). Ed. M.F.
Zhukov, Novosibirsk, Nauka Press,1977.
2. Hubbell J.H., Veigele W.J.,Briggs E.A., Brown R.T., Cromer D.T., Howerton R.J.
J.Phys.Chem.Ref. Data, &(I9751
471.
3. Hubbell J.H. Radiat.Res.,E(1977) 58.
4. Kupliauskis Z.J., Kupliauskiene A.V., Izv. WZov SSSR.Fizika, No 4(1976) 95.
