The newly improved set-up at the Planetary Spectroscopy Laboratory (PSL)

Kurzfassung

The Planetary Spectroscopy Laboratory (PSL) of DLR in Berlin provides spectral measurements of primarily planetary analogues from the visible to the far-infrared range. PSL has supported the data analysis as well as the development and calibration of instruments for planetary missions from ESA, NASA and JAXA. For this purposes PSL provides reflection, transmission and emission spectroscopy of target materials. Currently PSL operates three identical Bruker Vertex 80V vacuum FTIR spectrometer (the third one just installed in June 2019), two spectrometers are equipped with aluminum mirrors optimized for the UV, visible and near-IR, the third features gold-coated mirrors for the near to far IR spectral range. External simulation chambers are attached to two of the instruments for emissivity measurements. The chamber at the near to far IR instrument allows emissivity measurements from 0.7-200 micron under vacuum for sample temperatures from 320K to above 900K, using an innovative induction system. The second chamber (purged with dry air and water cooled to <=270K) allows emissivity measurements of samples with surface temperature from 290K to 420K. We measure bi-directional reflectance of samples; with variable incidence and emission angles between 0° and 85° (minimum phase angle is 26° to prevent damages to the mirrors). Samples are measured currently at room temperature and 170K, with a planned extension for temperatures below 100K, by means of a new external chamber, whose funding is accepted and will be available in 2020. Bi-directional and hemispherical reflectance is measured under purging/vacuum conditions, covering the 0.2 to above 200 micron spectral range. An FT-IR microscope installed at the end of 2018, allows microscopic analysis in transmission and reflectance in the VIS+VNIR+MIR spectral range. Transmission of thin slabs, optical filters, optical windows, pellets, and others is measured in the complete spectral range from UV to FIR using a parallel beam configuration to avoid refraction.