A simulation chamber for absorption spectroscopy in planetary atmospheres

Abstract. A novel simulation chamber PASSxS (Planetary Atmosphere Simulation System for Spectroscopy) has been developed for absorption measurements performed with a Fourier Transform Spectrometer (FTS) and, possibly, a cavity ring down (CRD) spectrometer, with a sample temperature ranging from 100 K up to 550 K, while the pressure of the gas can be varied from 10 mbar up to 60 bar. These temperature and pressure ranges cover a significant part of the planetary atmospheres in the solar system and the absorption chamber can thus be used to simulate planetary atmospheres of solar planets and extra solar planets with similar atmospheres. The optical absorption path for the FTS absorption measurements is 3.2 m, due to the implementation of a multipass setup inside the chamber. The FTS measurements cover a wide spectral range, from the visible to the mid-infrared with a sensitivity sufficient for medium strength absorption bands. The FTS has been used previously to measure high pressure atmospheres, including collision induced absorption bands and continuum absorption at ambient temperatures. PASSxS allows to measure the temperature dependence of collision induced bands and continuum absorption, which is important both for the modelling of planetary atmospheres as well as for fundamental processes involving collisions between molecules and atoms.