Averaged fractional charge loss curves for all AF2-9 CCDs, binned over 24 h. The downward-pointing arrows indicate the times of controlled heating events where the trapping increases because the emission time constants of slow-release traps are reduced, allowing them to empty within the charge injection period and therefore able to trap from the next block of injected lines. The upward-pointing arrows correspond to time of scans along the Galactic plane. During these prolonged periods of high-density star regions there are more photoelectrons than normal flooding the FPA and keeping traps filled in between charge injections, thus leading to temporary reductions in the number of electrons trapped from the charge injection lines. Two solar proton events which clearly impacted on the FPR are also marked. The plot covers a time span of approximately 19 months.