MEDIASE

MEDIASE (Moyen d'Essai et de DIagnostic en Ambiance Spatiale Extrême, Test and Diagnostic Facility under Extreme Space Environment) is a stainless steel chamber for the MWSF's focus equipped with a hemispherical silica glass window, a water-cooled front shield surrounding a water-cooled sample holder.

The material specimen, up to 90 mm wide and 2 to 4 mm thick, is heated by the solar energy concentrated at the focus of the solar furnace, under high vacuum or any controlled atmosphere.

On the back face of the sample, a water-cooled shield protects the instruments from the irradiance energy of the sample, and also shields it from radiative exchange with the surroundings.

Several measurements are possible, under solar heating alone, or combined with ion and/or UV irradiation, by adding an ion source capable of delivering up to 1021 ions m-2 s -1 under 5 keV and/or a UV source:

The THEMIS solar tower offers two experimental areas:

  • Temperature, using a two-colour optical fiber pyrometer or a pyro-reflectometer,
  • total (0.6 to 40 um) or spectral directional (0 to 80°) emittance, using a total radiometer through a window and a 3-mirror goniometer, these measurements leading to the total or spectral directional emissivity of the material,
  • quantitative mass loss, using a quartz crystal micro-balance (under vacuum only),
  • qualitative mass-loss, by measuring the neutral and/or ionised residual and emitted species from the material with an open source mass spectrometer (under vacuum only).

MEDIASE has been used to heat samples up to 2500 K under a residual pressure from 10-7 hPa (cold sample) to 5 10-5 hPa (sample at 2400 K).