Single Event Tolerance of X-ray SOI Pixel Sensors

TL;DR

This study assesses the single event upset tolerance of XRPIX, an X-ray SOI pixel sensor for space, by measuring its response to heavy ion irradiation and estimating its in-orbit SEU rate, demonstrating negligible risk.

Contribution

It provides the first measurement of SEU cross-section and threshold LET for XRPIX, enabling reliable in-orbit operation predictions.

Findings

SEU saturation cross-section is approximately 3.4×10^{-10} cm^2/bit.

Threshold LET for SEU is about 7.3 MeV/(mg/cm^2).

Estimated in-orbit SEU rate is less than 0.1 events per year.

Abstract

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 MeV/(mg/cm2) to 68 MeV/(mg/cm2). From the SEU cross-section curve, the saturation cross-section and threshold LET are successfully obtained to be $3.4^{+2.9}_{-0.9}\times 10^{-10}~{\rm cm^2/bit}$ and $7.3^{+1.9}_{-3.5}~{\rm MeV/(mg/cm^2)}$, respectively. Using these values, the SEU rate in orbit is estimated to be $\lesssim$ 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.