Study of x-ray and L-REC photon emissions from highly ionized swift and projectiles passing through a thin carbon foil

Abstract

X-rays and L-shell radiative electron capture (L-REC) photons have been detected from highly ionized swift projectiles of and passing through a thin carbon foil at two incident projectile energies. All the K and L peaks show strong shifts towards higher energy as a result of multiple ionization of L- and M-shells. The intensity ratios have been found to be almost half of the value for the singly ionized atoms. The measured positions of various L and K x-ray peaks and the measured intensity ratios have been attributed to certain types of electronic configurations based on the extensive multiconfiguration Dirac-Fock calculations. Generally, it has been found that the lowest-energy configuration plays a rather small role, but in contrast the excited configurations with holes in the L-shell and with occupied 3d, 4s, 4p, 4d or higher subshells seem to be very important. The relative L-REC cross section between higher and lower projectile energies shows excellent agreement with the results obtained under the non-relativistic dipole approximation.