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In this work, measurements were taken to investigate the robustness of a GaN HEMT to TID by a 60CO Source. These results will be compared with a previous X-ray based work. The robustness was investigated through IxV curves and characteristic parameters of the irradiated device. The analysis included data acquired both from on- and off- state modes. The work concludes that the device is robust to TID, as it quickly recovered important parameters. Mainly, the on-state mode, which presented a better performance compared to the off-mode. An analogous behavior was seen for X-ray. Finally, the VTH values due to the TID, in this device is independent of the dose rate and the radiation source.

This work aims to study the effects of ionizing radiation on a half-wave rectifier circuit. The diodes of the circuit, rectifier and Zener, were exposed to X-rays of 10 keV of effective energy. The characteristic curves of both diodes were evaluated before and after being subjected to cumulative total ionizing dose (TID) effects. The accumulation of charges in the dielectric structures of the diodes alter their individual functionalities, but the changes verified in the rectification were irrelevant. In this study, three irradiation methods were used to correlate the physical mechanisms responsible for the effects caused by radiation with variations in the electrical parameters of the devices and the efficiency of the rectifier circuit.

Gallium nitride commercial transistors (GaN FET) are great candidates as power devices tolerant to the effects of Total ionizing dose (TID). Therefore, we have evaluated its robustness by analysing parameters in its characteristic parameters. Devices were exposed to a 10 keV X-ray source accumulating a total of 350 krad(Si). However, results indicate that the tested components are more tolerant to the effects of TID when in on-state mode rather than the off-mode, that is, when the device is working, which is good news for COTS applications in environments subject to the effects of ionizing radiation.

This work presents results of three distinct radiation tests performed upon a fault-tolerant data acquisition system comprising a design diversity redundancy technique. The first and second experiments are Total Ionizing Dose (TID) essays, comprising gamma and X-ray irradiations. The last experiment considers single event effects, in which two heavy ion irradiation campaigns are carried out. The case study system comprises three analog-to-digital converters and two software-based voters, besides additional software and hardware resources used for controlling, monitoring and memory management. The applied Diversity Triple Modular Redundancy (DTMR) technique, comprises different levels of diversity (temporal and architectural). The circuit was designed in a programmable System-on-Chip (PSoC), fabricated in a 130nm CMOS technology process. Results show that the technique may increase the lifetime of the system under TID if comparing with a non-redundant implementation. Considering the heavy ions experiments the system was proved effective to tolerate 100% of the observed errors originated in the converters, while errors in the processing unit present a higher criticality. Critical errors occurring in one of the voters were also observed. A second heavy-ion campaign was then carried out to investigate the voters reliability, comparing the dynamic cross-section of three different software-based voter schemes implemented in the considered PSoC.