Polarization of a Two-Electron, One-PhotonKX-Ray Transition

We have observed a large linear polarization for the low-energy $K\alpha$ x-ray satellite, $K{L}^1$ radiative electron-rearrangement (RER) ($1s^{-1\mathrm{}}2p^{-1\mathrm{}}{}_{}{}^1{}_{}{}^{}P_1^{}{}_{}{}^{}-2\mathrm{}{s}^{-2\mathrm{}}{}_{}{}^1{}_{}{}^{}S_0^{}{}_{}{}^{}$) two-electron, one-photon transition, in Si and Al targets when bombarded by 2.0-MeV He. This observation supports the interpretation of the origin of the $K{L}^n\mathrm{RER}$ satellites since both the $K{\alpha }^{\prime }$ polarization and the $K{L}^1\mathrm{RER}$ polarization reflect the nonstatistical population of the magnetic substates of the initial state.