 The Xenon Arc light source emits a spectral
power distribution which can be filtered to closely match sunlight at
UV wavelengths. The water cooled Xenon arc with a borosilicate inner and
outer filter, is currently the closest simulation of sunlight across the
entire UV spectrum. Other conditions can be controlled: water spray to
the specimen, temperatures and humidity so the overall effect is similar
to natural weathering. The acceleration factor is provided by higher radiant
intensities, longer light-on duration, higher temperatures, and more prolonged
moisture cycling. Other filter combinations are used to match different
sunlight effects: for instance, borosilicate inner and soda lime outer
filters will produce a spectrum similar to sunlight through window glass.
The xenon arc light source should be used whenever good agreement with
outdoor testing is the major goal of testing. The xenon arc conforms to
many specifications including ASTM G155, SAE J 1960, SAE J 1885 amd AATCC
Method 16E, F. |
