Upper-limit determination of resonant trielectronic recombination cross-section for krypton using crystal channeling

Abstract

We used channeling through a thin crystal to get an estimate of the cross section of the resonant trielectronic capture by ${\mathrm{Kr}}^{34+}$ ions. K x-ray--$K$ x-ray coincidence measurements were performed with a selection on the charge state and energy loss of transmitted ions. An upper limit of $1.9\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}27} {\mathrm{cm}}^{2}$ at the resonance is obtained, and this represents an improvement by two orders of magnitude with respect to previous ion-gas experiments. The possibility to reach the theoretical predictions experimentally is discussed.