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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-21 20:52 |
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Conference: Bucharest University Faculty of Physics 2008 Meeting
Section: Theoretical Physics and Applied Mathematics Seminar
Title:
A theoretical investigation of K-shell Compton scattering at high energy
Authors:
Viorica Florescu(1), R.H. Pratt(2)
Affiliation:
1) Faculty of Physics, University of Bucharest
2) University of Pittsburgh, Pittsburgh, PA, 15260, USA
E-mail
Keywords:
Abstract:
The high energy regime of Compton scattering (1/m > 1, with 1 the incident photon
energy) is little investigated. As the most accurate existing codes devoted to this process
do not cover this regime, other approaches are needed. At the present stage the high
energy regime for the case of a K-shell electron can be explored by two approaches: RIA
-the relativistic impulse approximation [1] and ER -the full IPA point Coulomb second
order S-matrix in the extreme relativistic limit [2]. The first approach, that can be used
for any shell, has been the object of several recent theoretical studies [3], which have
shown its usefulness in the hundreds of keV regime. The second approach was studied
only for a K-shell electron, and its predictions have been not confronted up to now with
any other calculations.
In our work we study the doubly (DDCS) and triply (TDCS) differential cross sections
for a K shell electron of a hydrogenlike atom within RIA and ER. Our main results are: i)
an analytic expression for the extreme relativistic limit of RIA; ii) a comparison between
the predictions of this formula and those of ER calculations. Both approaches predict a
decrease as 1/1 for DDCS in the high energy limit, and apart from this, a dependence
on the same three variables, namely Z- the nuclear charge, - the ratio of the scattered
and incident photon energies, and 21 sin2 /2 , with the photon scattering angle.
In the cases investigated up to now we find that the corresponding limit given by RIA for
DDCS is in agreement with the ER limit results for low Z values; the difference of less
2% at Z=29 increseases up to 10% for Z = 82.
1. R. Ribberfors, Phys. Rev. B 12, 2067 (1975)
2. V. Florescu and M. Gavrila, Phys. Rev. A 68, 052709 (2003)
3. R. H. Pratt et. al., NIMB 261, 175 (2007)
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