On the NASA 2020 rover mission to Jezero crater, the remote determination of the texture, mineralogy and chemistry of rocks is essential to quickly and thoroughly characterize an area and to optimize the selection of samples for return to Earth. As part of the Perseverance payload, SuperCam is a suite of five techniques that provide critical and complementary observations via Laser-Induced Breakdown Spectroscopy (LIBS), Time-Resolved Raman and Luminescence (TRR/L), visible and near-infrared spectroscopy (VISIR), high-resolution color imaging (RMI), and acoustic recording (MIC). SuperCam operates at remote distances, primarily 2–7 m, while providing data at sub-mm to mm scales. We report on SuperCam’s science objectives in the context of the Mars 2020 mission goals and ways the different techniques can address these questions. The instrument is made up of three separate subsystems: the Mast Unit is designed and built in France; the Body Unit is provided by the United States; the calibration target holder is contributed by Spain, and the targets themselves by the entire science team. This publication focuses on the design, development, and tests of the Mast Unit; companion papers describe the other units. The goal of this work is to provide an understanding of the technical choices made, the constraints that were imposed, and ultimately the validated performance of the flight model as it leaves Earth, and it will serve as the foundation for Mars operations and future processing of the data.
This paper describes the design of a power-cycling test bench to study the reliability of power-GaN-HEMT power switches. The aim of the presented paper is to study the measurable electrical consequences of internal degradation with aging. The shift of these measured parameters can be considered as reliability indicators. With the aim to decorrelate thermomechanical effects from internal GaN-specific degradation, the temperature was limited by choosing the stress parameters with the use of an infrared camera. The power-cycling test was designed with GaN-specific gate drivers to consider the pGaN-gate requirements. Thorough the power-cycling test we have tracked the evolution of electrical parameters that have been identified as degradation indicators. Finally, we have studied the link between the stress parameters and the degradation, as well as the correlation between different degradation indicators.
This paper studies the impact of the aging on power GaN transistors in switching conditions. The devices under test are commercial discrete enhancement mode gallium-nitride HEMT. We present a power cycling test platform that controls the switching conditions such as frequency, duty cycle, and gate voltage; as well as drain current and drain voltage. We have measured specific parameters before and after the power cycling in order to detect indicators for each drift effect. We measure not only the electrical parameters given by datasheet, but also the traps causing Dynamic On-State Resistance, an specific drift effect of this technology which compromises high frequency efficiency in switching power converters.
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