Distorted-wave ionization and x-ray production cross sections ofthe K shell of Cu and the L shells of Ag, In, and Sn by positron impact

M. DINGFELDER; S. SEGUI; J. M. FERNÁNDEZ-VAREA

PHYSICAL REVIEW A - ATOMIC, MOLECULAR AND OPTICAL PHYSICS

APS

Año: 2008 vol. 77 p. 627101 - 627108

1050-2947

We study the ionization cross sections of the K shell of Cu and the L shells of Ag, In, and Sn by p ositron impact using the distorted-wave Born approximation, focusing on the near-threshold energy range (below 40 keV) to compare with recent measurements. The distorted-wave formalism proves to b e an appropriate approach, esp ecially to describ e the shap e of the cross-section curves forp ositrons accurately. Furthermore, we calculate x-ray production cross sections of the considered L shells having recourse to two sets of atomic relaxation parameters involved in the conversion from ionization to x-ray production cross sections. The 5 –10% differences in the theoretical values calculated with these parameter sets are apparently not large enough to explain the discrepancy between the distorted-wave curves and the experimental data, particularly for Ag. Other sources of uncertainty that could be affecting these comparisons are discussed.