Auger decay of neon following energetic ion bombardment

Abstract

A high-resolution double-focusing electrostatic electron analyzer has been used to resolve Ne Auger electrons produced by 0.15-6.0-MeV ${\mathrm{H}}^{+}$, 1.0-MeV ${\mathrm{He}}^{+}$, and 33-MeV ${0}^{5+}$ bombardment. Individual $K$-Auger satellite lines stemming from the decay of multiply ionized neon have been observed. The energies, relative intensities, and production probabilities of these satellite lines were measured as a function of the projectile $Z$ and as a function of proton bombarding energy. Tentative identifications for all observed lines were made by comparison with calculated Auger satellite transition energies. The reliability of the Hartree-Fock calculations used was demonstrated by comparison with ${e}^{\ensuremath{-}}+\mathrm{Ne}$ data and by comparing calculated x-ray transition energies for multiply ionized neon to recent measurements of O + Ne x-ray lines. A rough estimate of the probability of single- and double-$2s$ orbital vacancy production as a function of $L$-shell defect was obtained. With proton bombardment, the satellite-production probability ${Q}_{s}$ was observed to decrease smoothly with increasing proton energy. The observation that ${Q}_{s}$ for 6-MeV proton bombardment was approximately equal to that obtained with equal-velocity electrons is believed to imply that electron shakeoff is the dominant $L$-shell ionization mechanism for high-energy proton bombardment.