Relativistic (e,2e) processes on atomic inner shells

Abstract

The investigation of electron impact ionization by the electron-electron (e, 2e) coincidence technique has until recently been restricted to the non-relativistic energy region (typically 10 eV to 10 keV). We report here on an (e,2e) experiment using a 500 keV electron beam impinging upon thin-foil targets. Absolute triply differential cmss sectiom and angular distributions for K-shell ionization of silver and gold were measured, showing appreciable discrepancis compared with theoretical predictions.

Relativistic (e, 2e) collisions on atomic inner shells in symmetric geometry

“…Our work demonstrates that the first-Born approximation is simply not adequate and a more refined calculation is required if we are to understand the physics of K-shell ionisation at these energies. The first-Born approximation is also inadequate for asymmetric collisions where it also overestimates severly the T D C S [9]. (We remark that spin flip is indeed less significant in this case (see Fig.…”

“…There it was possible to measure the absolute triple differential cross section for K-shell ionisation of atoms with higher atomic numbers (Z = 47 and 73) using an energy-sharing method. These experiments have been continued with improved technical facilities [8] and recently triple differential cross sections have been reported for the K-shell ionisation for silver and gold both in coplanar asymmetric and symmetric geometries [9]. In this paper we report on the extension of the symmetric experiment to copper ( Z = 29).…”

The Triple Differential Cross Sections for Electron Impact Ionization of Metastable 3s State Hydrogen Atoms with Exchange Effect

“…The triple differential cross-section (TDCS) in electron hydrogen atom ionization collision has become increasingly interesting over the last four to five decades both theoretically and experimentally for relativistic [2]- [9] as well as for non-relativistic energies [10]- [21]. Triple differential cross-section (TDCS), measured in (e, 2e) coincidence experiment investigated first by Ehrhardt et al [22] and Amaldi et al [23].…”

Theoretical analysis of the relativistic first order Born approximation for inner shell (e, 2e) processes

“…For a number of years, substantial discrepancies existed between the absolute experimental data for triple differential cross sections (TDCS) for electron impact ionization of inner shells of high-Z atoms obtained by Nakel and collaborators [1][2][3][4][5] and the results of theoretical calculations of these processes [4,[6][7][8][9][10][11][12]. However recently, definite progress towards quantitative agreement between theory and experiment could be achieved with the implementation of a fully relativistic distorted wave Born approximation (rDWBA) [13][14][15].…”