Abstract: A method of producing a radiating plasma with an increased flux stability and uniformity is disclosed. The method comprises the steps of generating a primary target by urging a liquid under pressure through a nozzle; directing an energy pre-pulse onto the primary target to generate a secondary target in the form of a gas or plasma cloud; allowing the thus formed secondary target to expand for a predetermined period of time; and directing a main energy pulse onto the secondary target when the predetermined period of time has elapsed in order to produce a plasma radiating X-ray or EUV radiation. The pre-pulse has a beam waist size that is larger, in at least one dimension, than the corresponding dimension of the primary target.

Abstract: In a method and an apparatus for generating X-ray or EUV radiation, an electron beam is brought to interact with a propagating target jet, typically in a vacuum chamber. The target jet is formed by urging a liquid substance under pressure through an outlet opening. Hard X-ray radiation may be generated by converting the electron-beam energy to Bremsstrahlung and characteristic line emission, essentially without heating the jet to a plasma-forming temperature. Soft X-ray or EUV radiation may be generated by the electron beam heating the jet to a plasma-forming temperature.

Abstract: A method and an apparatus is designed to produce X-ray or EUV radiation for use in lithography, microscopy, materials science, or medical diagnostics. The radiation is produced by urging a substance through an outlet (6) to generate a microscopic jet (2) in a direction from the outlet (6), and by directing at least one energy beam (1′) onto the jet (2), wherein the energy beam (1′) interacts with the jet (2) to produce the X-ray or EUV radiation. The temperature of the outlet (6) is controlled to increase the directional stability of the jet (2). The thus-achieved directional stability of the jet (2) provides for reduced pulse-to-pulse fluctuations of the produced radiation, improved spatial stability of the radiation source, as well as high average power since the energy beam (1′) can be tightly focused on the jet (2), even at a comparatively large distance from the jet-generating outlet (6).

Abstract: In a method and an apparatus for generating X-ray or EUV radiation, an electron beam is brought to interact with a propagating target jet, typically in a vacuum chamber. The target jet is formed by urging a liquid substance under pressure through an outlet opening. Hard X-ray radiation may be generated by converting the electron-beam energy to Bremsstrahlung and characteristic line emission, essentially without heating the jet to a plasma-forming temperature. Soft X-ray or EUV radiation may be generated by the electron beam heating the jet to a plasma-forming temperature.