Angle-resolved x-ray spectroscopic scheme to determine overlapping hyperfine splittings in highly charged helium-like ions

Abstract

An angle-resolved x-ray spectroscopic scheme is presented for determining the hyperfine splitting of highly charged ions. For helium-like ions, in particular, we propose to measure either the angular distribution or polarization of the $1s2p{}^3{P}_1,F\to 1s^2{}^1{S}_0,F_f$ emission following the stimulated decay of the initial $1s2s{}^1{S}_0,F_i$ level. It is found that both the angular and polarization characteristics of the emitted x-ray photons strongly depends on the (relative) \textit{splitting} of the partially overlapping hyperfine $1s2p{}^3{P}_1,F$ resonances and may thus help resolve their hyperfine structure. The proposed scheme is feasible with present-day photon detectors and allows a measurement of the hyperfine splitting of helium-like ions with a relative accuracy of about $10^{-4}$.

5 pages, 3 figures