Fe^13+^, Fe^16+^, Fe^17+^ cross-section measurements

The ions were recirculated using an ion storage ring. Data were collected after a sufficiently long time that essentially all the ions had relaxed radiatively to their ground state.

For single ionization of Fe^13+^, we find that previous single pass experiments are more than 40% larger than our results. Compared to our work, the theoretical cross section recommended by Arnaud & Raymond (1992ApJ...398..394A) is more than 30% larger, while that of Dere (2007, J/A+A/466/771) is about 20% greater. Much of the discrepancy with Dere is due to the theory overestimating the contribution of excitation-autoionization via n=2 excitations.