[en] Experiments were done under ²⁵²Cf and ⁶⁰Co γ source to study the relation between heavy ion Single Event Upset (SEU) cross sections and γ accumulated doses. There was no obvious rule and little influence of γ accumulated doses on SEU cross sections when Static Random Access Memories were in power off mode and static power on mode. In active measuring mode, the SEU cross section increased as the accumulated doses increasing when same data were written in memory cells. If reverse data, such as '55' and 'AA', were written in memory cells during the experiment, the SEU cross sections decreased to the level when memories were not irradiated under ⁶⁰Co γ source, even more small. It implied that the influence of γ accumulated doses on SEU cross sections can be set off by this method