Pulsed Xenon Light Source

Overview

This light source, developed especially for laser photolysis spectrometers, features a pulsed 150W xenon arc lamp. The lamp runs in conventional cw mode with its operating current increased significantly for a few milliseconds when increased photon flux is required.

Optimisation of the electrical discharge characteristics (using resistive and inductive elements added to the discharge circuit), ensures that for part of the discharge period, the increased light level is kept at a constant level. When the output from a pulsed laser, used as the actinic source, is synchronised with the beginning of the plateau region, up to 500µs is available for recording changes in absorbance (ie. changes which mirror the concentration changes of intermediates in the laser initiated reaction). When slower reactions or longer lived species are being measured, the pulsing action is disabled and the light source is used in regular cw mode.