referred lamps are the reflector lamp HXP R120W45C VIS or UV of the company Osram® with an electric power of 120 watt or 200 watt or an UHP (Ultra High Pressure) lamp of the company Philips® in a similar electrical power range, for example. The elliptoid reflector can also be a UV reflector with a specially high reflectivity in the UVB, UVA and blue range of the spectrum, wherein the reflector in the green-yellow-red spectral range has a lower reflectivity. Other lamp types are conceivable as radiation sources such as high-pressure Xe lamps, even pulsed Xe lamps or high-pressure or medium-pressure Hg lamps or tungsten halogen lamps or one or several LED arrays emitting in the UVA range at 365 nm or in the violet spectral range around 405 nm, for example.