Single event tolerance of x-ray silicon-on-insulator pixel sensors

We evaluate the single event tolerance of the x-ray silicon-on-insulator (SOI) pixel sensor named XRPIX, developed for the future x-ray astronomical satellite FORCE. In this work, we measure the cross-section of single event upset (SEU) of the shift register on XRPIX by irradiating heavy ion beams with linear energy transfer (LET) ranging from 0.022 to 68 MeV / ( mg/cm(2) ) . From the SEU cross-section curve, the saturation cross-section and threshold LET are successfully obtained to be 3.4(-0.9)(+2.9)x10(-10) cm(2)/bit and 7.3(-3.5)(+1.9) MeV/(mg/cm(2)), respectively. Using these values, the SEU rate in orbit is estimated to be <= 0.1 event / year primarily due to the secondary particles induced by cosmic-ray protons. This SEU rate of the shift register on XRPIX is negligible in the FORCE orbit.