Patent ID: 8742370

Claim:
A gas sensor comprising: a chamber for containing a gas sample in use; a radiation source adapted to emit radiation within a first waveband; within the chamber and positioned to receive radiation from the radiation source, a photoluminescent material which, upon absorption of radiation of a first wavelength within the first waveband, emits radiation of a second wavelength, the photoluminescent material being responsive to the presence of a target gas species in the gas sample such that the intensity of the emitted radiation varies according to the concentration of the target gas species in the gas sample; a luminescence detector assembly positioned at a first location at which radiation emitted by the photoluminescent material can be received, the luminescence detector assembly being adapted to detect radiation of the second wavelength and output a corresponding measurement signal related to the concentration of the target gas species in the gas sample; and an optics assembly adapted to receive radiation emitted by the radiation source and to converge the radiation away from the first location and towards a second, different, location at which the luminescence detector assembly cannot receive radiation.