Abstract: A foil trap is located in a path of a radiation beam. The foil trap includes an array of conductive strips. A voltage application circuit is coupled to the strips to apply voltage differences between pairs of adjacent ones of the strips. The voltage application circuit includes a current limiting circuit arranged to limit currents to the strips to values below a threshold value above which self-sustained arc discharge may arise in the foil trap.

Abstract: An assembly for detection of at least one of radiation flux and contamination on an optical component includes a detector configured to receive at least one of the radiation flux and contamination, and when the assembly is in use, to generate a detector signal correlated to at least one of the radiation flux and contamination on the component. A meter is configured to measure the detector signal. The detector includes at least one wire.

Abstract: A radiation system includes a contamination barrier, e.g., a foil trap, between a collector, for example a normal incidence collector, and a radiation source, such that radiation coming from the source passes the foil trap twice. The radiation passes the contamination barrier once before hitting the collector and a second time after reflection by the collector. The foil trap includes lamellas that are parallel to both the radiation coming from the light source, and to the radiation reflected by the collector. The radiation is thus not obstructed by the foil trap. In this way, a normal incidence collector, which is used with a plasma produced source, can be protected from debris coming from a EUV source.