We have used an x-ray-x-ray coincidence experiment to confirm the validity of an independent sharing model for double K" vacancieSo As well as providing a basis for studying vacancy sharing and double-hole production, this technique permits us to determine variations in the fluorescence yields of hypersatellite states, In this Letter we report the results of an x-rayx-ray coincidence study of the /C-shell vacancies produced in a heavy-ion collision experiment, and emphasize the power of this technique to determine quantitatively (1) the probability for production of double K vacancies in heavy-ion collisions; (2) the distribution of double K holes shared between the separating collision partners; and (3) the hypersatellite transition energy in each of the highly ionized collision partners.Spectroscopic observations by Woods et al.^ of the K x-ray lines from energetic CI ions have shown the hypersatellite intensity reaching ^7% of the single-/C-hole satellite transitions showing that the mean probability {--ojo^ for production of a second K vacancy is large in nearly symmetric atomic collisions. To evaluate all double-i^-vacancy production, however, one must include the probability W^^ for one vacancy in each collision partner as well as W^j^ and W^^ for the occupation of the spectroscopically observable states with both holes in the same partner. This has been readily done in the present coincidence experiment.Coincidences between K x-ray hypersatellites and the corresponding satellite transitions in a single atom have been observed previously, for example, by Briand et al.,^ using radioactive sources. Because of the much larger ionization probability in heavy-ion collisions, random events are more easily removed, leaving a true coincidence spectrum rich in detail of the satellite and hypersatellite transitions in both collision partners.Considering vacancy sharing, it has been pointed out by Meyerhof^ and confirmed by detailed theoretical calculations'* that a model of charge exchange by radial coupling between states with a constant energy defect (AE) adequately describes the sharing of a single K vacancy in the 2p(j orbital to the heavy-collision partner {Iso) with a probability W= {1 + ex^yAE)'^,The extension of the sharing model for two K holes in the 2pG level is readily obtained when it is assumed that the two holes are uncorrelated. By considering that the transfer of each hole depends on the location of the second hole, and consequent bindingenergy differences, this model gives the double vacancy sharing distribution (1) where the subscripts L and H on the sharing probability W indicate use of the AE values relevant when an extra K hole is present in the lighter or heavier partner. The applicability of this model is confirmed in the present coincidence experiment with S-Ar collisions at 1 MeV/amu for various charge states of the incident sulfur ions.The details of the experimental techniques and data analysis will be given in a future publica-tion^ and are only summarized briefly here. Following post str...
