Measurement of dielectronic recombination inHe+ions

Dielectronic recombination was investigated for ${\mathrm{He}}^{+}$, the simplest ion for which this process is possible. This work was done using the light-ion storage ring and electron cooler at the Indiana University Cyclotron Facility. Resonant recombination yields resulting from 1s+${\mathit{e}}^{\mathrm{-}}$→nln’l’ transitions were observed with sufficient resolution (about 1 eV in the center of mass) to isolate and obtain cross sections for the 2s2p ${}_{}{}^3{}_{}{}^{}$ ${\mathit{P}}^{\mathit{o}}$ and 2${\mathit{p}}^2$ ${}_{}{}^1{}_{}{}^{}$D terms. The measured cross sections, integrated over the Δn=1 2ln’l’ states, agree in magnitude with theoretical calculations. Additionally, Δn=2 dielectronic recombination events associated with 3ln’l’ intermediate states were observed.