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Optical Measurement Systems and Special Experiments under Space Conditions

At the Department Facilities and Solar Materials of the DLR Institute of Solar Research, there is equipment to launch concentrated solar radiation and also the radiation of different artificial light sources into a vacuum chamber. Samples with a diameter of up to 0.5 meters can be irradiated under vacuum conditions. Moreover, it is possible to provide these experiments with a liquid-nitrogen cooling. In this way, space-like conditions can be achieved.

To operate the space experiments there are available vacuum chambers with different sizes. The radiation of various light sources (UV, IR, HLS, SOF, etc.) can be launched into the chambers through a quartz glass window (diameter 500 mm). High energy flux, low temperatures (around 80 K), and lacking convection form the basic conditions for many experiments performed for the qualification of materials and components demanded by the space industry, such as solar panels, optical detectors, mechanical components such as harnesses and hinges, radiation shields, and covers. A powerful data acquisition system allows allocating all necessary data. Among other things "flux maps" can be compiled that represent the distribution of the radiation flux density in the image plane of the experiment, most accurately. Long-time tests up to 1,000 hours under UV-radiation have been carried out, and experiments with uniform irradiance of up to 36 kW/m² on an area of 0.3 x 0.3 m² were executed. To monitor the cleanliness of the chamber during the experiments, a mass spectrometer and infrared-transparent CaF2 glasses as witness plates can be attached, whose covering with contaminants can be determined qualitatively by means of Fourier transform infrared spectroscopy.

Vacuum chamber : Diameter 1090 mm; Length 1200 mm

360 Watts UV-A Irradiator

Optical Laboratory

• HYCAL-calorimeters and radiometers to determine high irradiances
• Spectrometer to determine transmissivity and reflectivity  (UV-VIS-NIR, FTIR, monochromator)
• Thermographic measurement systems to determine emissivity and/or temperature of surfaces in the Infrared regime
• UV-A/B radiometers
• A goniometer-reflectometer optical bench to determine angle dependent reflectivity and emissivity
• Various CCD-cameras
• Black body
• Measurement systems to execute physical irradiation experiments: 360 watts UV-A, 500 watts IR radiator
• Each experiment can be calibrated by means of a flux density measurement with high resolution

Vacuum Laboratory

There are two vacuum chambers available in the vacuum laboratory including pumping systems and a wide variety of measurement techniques:
1. chamber: Diameter 1090 mm, depth 1200 mm
2. chamber: Diameter 600 mm, depth 500 mm
into which the radiation of various light sources (UV, IR, HLS, SOF, etc) can be launched through a quartz glass window  (Diameter 500 mm).

• Both chambers can be equipped with water- or nitrogen cooling or an electrical heating to control the temperature of the sample.
• A powerful data acquisition system with 80 channels collects all relevant data (temperature, current, voltage, pressure, etc.)
• The gas composition can be permanently  (at p < 10-4 mbar) monitored by means of a residual gas analyzer
• Moreover it is possible to equip the chamber with CaF2 witness plates (IR transparent) whose coverage can be determined qualitatively by means of Fourier-transformations-infrared-spectroscopy.