Abstract: A radiation system to generate a radiation emitting plasma, the radiation system include a fuel emitter to provide a fuel target at a plasma formation region, a first laser arranged to provide a first laser beam at the plasma formation region incident on the fuel target to generate a radiation emitting plasma, an imaging device arranged to obtain a first image of the radiation emitting plasma at the plasma formation region, the first image indicating at least one image property of the radiation emitting plasma, and a controller. The controller is arranged to receive the first image, and to generate at least one instruction based on the at least one image property of the radiation emitting plasma to modify operation of at least one component of the radiation system to reduce a detrimental effect of debris.

Abstract: A radiation system to generate a radiation emitting plasma, the radiation system include a fuel emitter to provide a fuel target at a plasma formation region, a first laser arranged to provide a first laser beam at the plasma formation region incident on the fuel target to generate a radiation emitting plasma, an imaging device arranged to obtain a first image of the radiation emitting plasma at the plasma formation region, the first image indicating at least one image property of the radiation emitting plasma, and a controller. The controller is arranged to receive the first image, and to generate at least one instruction based on the at least one image property of the radiation emitting plasma to modify operation of at least one component of the radiation system to reduce a detrimental effect of debris.

Abstract: The present invention relates to a method and device for generating optical radiation, in particular EUV radiation or soft x-rays, by means of an electrically operated discharge. A plasma (15) is ignited in a gaseous medium between at least two electrodes (1, 2), wherein said gaseous medium is produced at least partly from a liquid material (6) which is applied to one or several surface(s) moving in the discharge space and is at least partially evaporated by one or several pulsed energy beams. In the proposed method and device at least two consecutive pulses (9, 18) are applied within a time interval of each electrical discharge onto said surface(s). With this measure, the collectable conversion efficiency is increased compared to the use of only one single energy pulse within each electrical discharge.