What is the Cold Surface Spectroscopy Facility?

The Cold Surfaces Spectroscopy Facility at Institut de Planétologie et Astrophysique de Grenoble (IPAG) Grenoble, France, is a facility of the Trans National Access Distributed Planetary Simulation Facility activity of the Europlanet 2024-RI program*

(* EPN 2024-RI received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreements N° 871149.)

It houses two unique home-made Spectro-Gonio Radiometers (SHINE and SHADOWS) that allows measurement of the bidirectional reflectance spectra and photometric distribution functions of various types of planetary materials (granular to compact) over almost the whole solar spectrum, from the visible to the near-IR (from 0.4 to 4.8 µm), with a high degree of radiometric accuracy (better than +/-0.5%) under most viewing geometries (illumination and observation up to almost 80°, all azimuths, phase angle > 4-10°).

The SHINE instrument is fully described in Brissaud et al. 2004, Appl. Optics, 43, 1926. The SHADOWS instrument is fully described in Potin et al. 2018, Appl. Optics, 57, 8279

The instruments are located in two dark cold room that can be cooled down to -20°C. They are fully automatized and the data calibration and reduction are made with homemade software.

Different types of measurements can be programmed with different environmental cryogenic cells:

  • simple reflectance spectra at one geometry (possibly with a samples varying with time, temperature, or physical/chemical process),
  • full BRDF with varying illumination (i) and observations (e, az) angles
  • limited angle BRDF spectra (when using cells),
  • or all these but only at a few selected wavelengths.

Spectro-Gonio Radiometer SHINE

with its stabilized monochromatic source (bottom left), the goniometer with illumination mirror, an open sample holder with sulfur powder and the detectors (right) and the goniometer and detection electronics (top left).

Micro Spectro-Gonio Radiometer SHADOWS

optimized for the measurement, at low temperature, of bidirectional reflectance spectra, over the visible and near-IR ( 0.35 to 4.8 µm), of very small dark and/or very fine grained samples (organics, meteorites, minerals) down to about 1 mm3 in volume.