Implementation of a “Design of Experiments” Methodology for the Prediction of Phototransistor Degradation in a Space Environment

Abstract

A Design Of Experiments (DOE) methodology was suggested to define an optimized irradiation test plan. In this paper, the proposed test plan was used to model the degradation of the main performances (photo and dark current) of silicon based phototransistors arrays with respect to the Total Ionizing Dose (TID) and to the Displacement Damage Dose (DDD), over a wide range of space-kind environments. The expected performance degradation after an 18-year Low Earth Orbit (LEO) mission was calculated using this model. End-Of-Life (EOL) prediction results were compared to experimental ones obtained on devices irradiated with a proton beam degrader that simulates the 18 year LEO environment. The excellent agreement found between theoretical and experimental data makes this methodology particularly valuable for the space qualification of such devices.Index Terms-Design of experiments, displacement damage dose, optical encoders, phototransistor, total ionizing dose.

Monte-carlo computations for predicted degradation of photonic devices in space environment

“…10 8 MeV/g. These last values have been used to compare the measured and the predicted results for both mean photo current and mean dark current [14].…”