Xenon lamps can be operated on a continuous DC basis or stroboscopically. All excitation lamps that operate in the lower UV range of wavelengths will produce ozone and, thus, they should be purged with a current of air. It should be born in mind that ozone absorbs strongly at 300nm and, thus, it must be purged from the light path of the spectrometer and sample, as it will interfere with the absorption measurements.