Disclosed is a contamination trap arrangement (300) configured to trap debris particles that are generated with the formation of a plasma within a radiation source configured to generate extreme ultraviolet radiation. The contamination trap comprises a vane structure (310) for trapping the debris particles; a heating arrangement (330) for heating the vane structure, the heating arrangement being in thermal communication with the vane structure; a cooling arrangement (350) for transporting heat generated as a result of the plasma formation, away from the vane structure, and a gap (370) between the heating arrangement and the cooling arrangement. The cooling arrangement is in thermal communication with the vane structure via the heating arrangement and the gap and the contamination trap also comprises a heat transfer adjustment arrangement operable to adjust the heat transfer characteristics of a fluid inside of the gap by providing for controllable relative movement between the surfaces defining the gap.