Gas and Aerosol Mass Spectrometer (GAMS) for Exploration of Planetary Atmospheres

We present a modified quadrupole ion trap mass spectrometer (QIT-MS) sensor and supporting experimental GAMS testbed optimized for planetary atmospheric analysis, with demonstrated operation under corrosive conditions relevant to Venus. The QIT-MS sensor is based on a Paul trap architecture with hyperbolic titanium alloy electrodes and alumina insulation spacers, designed for precise ion confinement and robust performance in chemically reactive environments. A corrosion-resistant yttria-coated iridium filament serves as the thermionic electron emitter, integrated into a modular electron gun assembly supporting both axial and radial ionization geometries. The sensor functions as a miniature pressure cell, allowing analyte introduction via fused silica capillaries and crescent-shaped inlets. The supporting testbed integrates custom high-voltage RF electronics, pressure-regulated sample delivery, and FPGA-based embedded control for real-time tuning of ionization parameters, voltage ramp profiles, and detector gating. Continuous operation in 98% concentrated sulfuric acid vapor was sustained over a three-month period, with no observable degradation in electron emitter performance or sensor functionality. Mass spectra recorded over this interval reveal characteristic ion fragment patterns of H₂SO₄, along with shifts due to thermal decomposition and protonation effects at elevated capillary temperatures (up to 425 K). Spectral analysis shows distinct fragmentation pathways and relative intensities that vary with capillary temperature, filament current, and electron energy, demonstrating the interplay between thermal and electron-induced dissociation mechanisms. Operational modes include a high-resolution, low-sensitivity scan for detailed fragmentation analysis, and a secular frequency suppression mode to selectively eject major ion species (e.g., CO₂⁺, N₂⁺) during ionization. These capabilities significantly enhance the detection of trace gases such as PH₃⁺, H₂S⁺, and their daughter ions. The flexible, miniaturized QIT-MS platform is supported by a custom RF tank and real-time monitoring electronics in a portable rack-mounted system. These results validate the QIT-MS sensor’s performance, chemical compatibility, and adaptability for deployment in future space missions targeting chemically diverse planetary atmospheres.