Lithographic apparatus, illumination system and debris trapping system

An illumination system configured to condition a radiation beam in a lithographic apparatus, the illumination system comprising:

• a source for generating radiation, and
• a debris trapping system for trapping at least some debris particles released with the generation of radiation,
• wherein the debris trapping system comprises
• (i) a first set of channels, each channel of the first set enabling radiation from the source to propagate therethrough and having an inner wall for catching debris particles;
• (ii) a second set of channels, situated downstream of the first set of channels with respect to a propagation direction of the radiation, each channel of the second set enabling radiation from the source to also propagate therethrough and having an inner wall for catching debris particles;
• and
• (iii) a gas supply and a gas exhaust configured to provide between the first set of channels and the second set of channels a gas flow having a net flow direction substantially across the propagation direction of the radiation.

A debris trapping system for trapping at least some debris particles released with the generation of radiation by a radiation source in a lithographic apparatus, the debris trapping system comprising:

• a first set of channels, each channel of the first set enabling radiation from a radiating source to propagate therethrough and having an inner wall for catching debris particles;
• a second set of channels, situated downstream of the first set of channels with respect to a propagation direction of the radiation, each channel of the second set enabling radiation from the radiating source to also propagate therethrough and having an inner wall for catching debris particles;
• and
• a gas supply and a gas exhaust configured to provide between the first set of channels and the second set of channels a gas flow having a net flow-direction substantially across the propagation direction of the radiation from a radiating source.