Charge equilibrium of relativistic uranium ions in matter

Abstract

Calculations are made for the electron capture and loss cross sections and the charge state distributions of uranium ions at energies of 200 MeV/nucleon, 437 MeV/nucleon and 962 MeV/nucleon colliding with low- Z and high- Z targets. The charge states of the projectile ions are determined from the equilibrium condition between electron loss from the ion and electron capture from a target atom into the projectile ion. The electron loss cross sections are formulated using the relativistic Born approximation. The electron capture process is considered to be non-radiative electron capture (non-REC) and radiative electron capture (REC) in the relativistic impact velocity range. The non-REC cross sections are calculated by Eichler's formula based on the eikonal theory, while for the evaluation of the relativistic REC process the contributions of internal e +e − pair creation and successive e +e − pair annihilation processes are taken into account in addition to the usual REC photon emission process.