Radiation system and lithographic apparatus

A lithographic apparatus comprising:

• a radiation system constructed and arranged to generate a beam of radiation defining in a radiation space, the radiation system comprising:
• a plasma produced discharge source constructed and arranged to generate extreme ultraviolet radiation, the discharge source comprising a pair of electrodes constructed and arranged to be provided with a voltage difference, and a system constructed and arranged to produce a discharge between said pair of electrodes so as to provide a pinch plasma between said electrodes;
• and
• a debris catching shield constructed and arranged to catch debris from said electrodes, to shield said electrodes from a line of sight provided in the radiation space, and to provide an aperture to a central area between said electrodes in said line of sight;
• a patterning device constructed and arranged to pattern the beam of radiation;
• and
• a projection system constructed and arranged to project the patterned beam of radiation onto a substrate.