Influence of projectile - nucleus interaction on relativistic electron-impact ionization

Abstract

We report (e, 2e) measurements at relativistic electron energy (300 keV) on the K shells of silver (E bind = 25.5 keV) and gold (E bind = 80.7 keV). Using coplanar asymmetric kinematics the angular distributions of the relative triply differential cross sections were measured. They are compared with results obtained using the relativistic distorted-wave Born approximation. For gold we find that the recoil peak is of the same order of magnitude as the binary peak. This is in good agreement with the theory which predicts a strong increase of projectile-nucleus interaction with increasing atomic number.

Cross sections of K-shell ionization by electron impact, measured from threshold to 100 keV, for Au and Bi

“…Although a deeper understanding of the collision dynamics can only be gained from experiments where fully differential cross sections are measured, many of these (e,2e) experiments yield relative distributions (see e.g. [33]), and then absolute total cross sections are needed to properly normalize such data. The reader is referred to the review article by Nakel and Whelan [34] for a thorough study of relativistic (e,2e) processes.…”

Spin asymmetry in relativistic (e,2e) processes: atomic-number dependence

“…These parameters are the same as in previous measurements of the (relative) triply differential cross sections of the K-shell ionization of copper, silver and gold using an unpolarized primary beam (Besch et al 1997, Sauter et al 1998. For the measurement of the Z dependence of the asymmetry we had to reduce considerably the statistical errors compared with the measurement of Prinz et al (1995) on the K-shell of silver.…”

“…beam axis requires that the nucleus balances the transverse momentum. Because of the significant electron-nucleus interaction the recoil region is very sensitive to the dynamics of the ionization process (see, e.g., Besch et al 1997, Sauter et al 1998. In particular, the electron-nucleus interaction should manifest itself in a significant increase of the asymmetry with Z in the recoil regime, while small asymmetries are expected in the binary region (Prinz et al 1995).…”