Lithographic apparatus and device manufacturing method

A lithographic apparatus comprising:

• a radiation system that provides a beam of radiation;
• a support structure that supports a patterning structure, the patterning structure configured to pattern the projection beam according to a desired pattern;
• a substrate support that supports a substrate;
• a projection system that projects the patterned beam onto a target portion of the substrate, said projection system including an optical element that has a beam exit area through which said patterned beam passes;
• and
• a fluid cleaning system that cleans a fluid to be introduced into a region in between said optical element and said substrate, said fluid cleaning system comprising
• a fluid inlet that receives fluid to be cleaned and a fluid outlet that supplies cleaned fluid to said region of said apparatus,
• a cleaning zone that cleans said received fluid, said cleaning zone being disposed between said inlet and said outlet, said cleaning zone including a nucleated surface provided with a plurality of nucleation sites, said cleaning zone being configured to receive radiation to cause dissociation of a contaminant present in said fluid in said cleaning zone.