Production of x rays beyond theK-series limit in gaseous and solid targets

Abstract

X rays of energy beyond the K-series limit have been detected during the bombardment of various low-Z, solid and gaseous targets by C/sup +/, N/sup +/, and O/sup +/ ions of energy 0.75 to 1.9 MeV. K..cap alpha cap alpha.. x rays, most likely from the transition (1s/sup -2/2p/sup -1/)..-->..(2s/sup -1/2p/sup -2/), are emitted by both collision partners in gaseous targets. The low-resolution energy measurements are in good agreement with published calculations. The relative yield from the heavier collision partner is larger than simple vacancy-sharing models would indicate, but electron screening may account for the excess. Molecular-orbital (MO) continuum radiation completely obscures the Kaa lines from thin solid carbon targets. The exponential shape of the MO spectrum beyond the united-atom limit is in reasonable agreement with collision-broadened spontaneous emission.