Filtered MHG lighting is a mature technology used since the 80’s for larger solar simulators inside environmental test chambers. MHG lamps are filled with a mixture of mercury, halides and rare earth elements which vaporize during ignition, generating a plasma. After a few minutes, the plasma reaches thermal equilibrium and emits a quasi-continuous spectrum (when properly filtered) similar to global solar radiation.
Currently, although optically filtered xenon lamps provide the best spectral match to natural solar radiation in the UV and visible portions of the spectrum, MHG technology exhibits two advantages over xenon. First, MHG are high efficiency sources and provide a higher output for electrical input and are better suited to large area illumination. Second, MHG emits lower amounts of infrared as compared to xenon, making thermal management easier. As with xenon, optical filters fine-tune the spectral irradiance to provide solar radiation outdoor or glass-filtered indoor solar radiation.
The technology, however, also exhibits some disadvantages. The spectral power distribution, for example, is directly dependent on plasma temperature. Changes in plasma temperature due to cooling/warming of luminaires, or changes to operating power (dimming) can have an immediate effect on the spectrum. Therefore, they are operated within a narrow power band; irradiance is determined by the distance.
The SolarConstant MHG series offers several luminaires based on MHG technology for high-end solar simulators. Special reflector designs guarantee the irradiance uniformity needed on your test object. For each new custom design, Atlas will run computer simulations with our proprietary modeling software to determine both the minimum number of SolarConstants required as well as their ideal positioning inside the chamber.
An Atlas team of professionals finally integrates the solar simulator into the environmental test chamber - either static or positionable/moveable in all spatial directions, depending on design.
