Abstract: A collector assembly with a radiation collector, a cover plate and a support member connecting the radiation collector to the cover plate are provided. The cover plate is designed to cover an opening in a collector chamber. The collector chamber opening may be large enough to pass the radiation collector and the support member. The removed radiation collector can be cleaned with different cleaning procedures, which may be performed in a cleaning device. Such cleaning device may for example consist of the following: a circumferential hull designed to provide an enclosure volume for circumferentially enclosing at least the radiation collector; an inlet configured to provide at least one of a cleaning gas and a cleaning liquid to the enclosure volume to clean at least said radiation collector; and an outlet configured to remove said at least one of said cleaning gas and said cleaning liquid from the enclosure volume.

Abstract: A rotatable contamination barrier for use with an EUV radiation system is disclosed. The contamination barrier has a blade structure configured to trap contaminant material coming from a radiation source, a bearing structure, coupled to a static frame, configured to rotatably bear the blade structure, and an eccentric mass element displaced relative to a central axis of rotation to balance the blade structure in the bearing structure.