A collective model for inner shell ionization

C. C. MONTANARI; D. M. MITNIK; J. E. MIRAGLIA

Caen

Congreso; 22nd International Symposium on Ion Atom Collisions; 2011

Universite de Caen Basse-Norrmandie and International advisory committee of the 22nd International Symposium on Ion Atom Collisions

Ionization of different shells has been studied, calculated and measured over the decades especially for the interest in the characteristic radiation from inner-shells. One of the most employed theories is the well known ECPSSR by Brandt and Lapicki [1], of probed efficacy in an extended energy range, and the usual input in the PIXE codes [2]. The goal of this work is to present an alternative fully theoretical calculation (no parameters included) specially suitable to describe inner shells of multiple electron targets such as L and M shells of Au, Pb, and Bi, or K-shell of Sb [3].  We use a collective response model, the shellwise local plasma approximation (SLPA) [4]. This model deals with each sub-shell of target electrons as an inhomogeneous electron gas with an ionization threshold. The only inputs are the theoretical wave functions of the ground state and the binding energies. In the case of Sb, known Hartree-Fock wave functions and energies are used. Instead, for Au, Pb, and Bi, the atomic wave functions were obtained in fully-relativistic way by solving numerically the Dirac equation. We will present the results for M-shell ionization of Au and Bi by O+q ions, L-shell ionization of Au and Pb by He2+, and for K-shell ionization of Sb by C, F and O ions. In all the cases the high energy region is considered. References [1] W Brandt et al, Phys.Rev. A 20, 465 (1979); G Lapicki, Nucl. Instrum. Methods in Phys. Res. B 189, 8 (2002). [2] G Lapicki, J. Phys. B. 42, 145204 (2009). [3] C. C. Montanari, D. M. Mitnik, and J. E. Miraglia, Rad. Effects and Def. in Solids 166, 338-345 (2011), [4] C C Montanari et al, Phys. Rev. A 73, 024901 (2006). [5] Czarnota et al, Phys. Rev. A 79, 032710 (2009).