The xenon source that supplies prime UV performance is focused onto the entrance slit of the excitation monochromator with an elliptical mirror. Besides ensuring efficient collection, the reflective surface keeps all wavelengths focused on the slit.
As an option an additional, software-selectable, xenon flash lamp can be fitted to enable phosphorescence studies.
The Emission Detector
Emission detector electronics employ photon-counting for the ultimate in low-light-level detection. Photon-counting concentrates on signals that originate from fluorescence emission, ignoring smaller signals originating in the detector tube (PMT). The more common method of analog detection (used by lower performance fluorometers) simply adds noise and signal together, masking weak emissions.