Patent ID: 6967341

Claim:
A method for generating a radiation of extreme ultraviolet range or soft x-ray range by gas discharge, the method comprising the steps of: arranging a first electrode and a second electrode concentrically surrounding the first electrode in a discharge vessel, wherein the first electrode is a hollow cathode having an electrode recess and wherein the second electrode has an electrode recess that is coaxial to the electrode recess of the hollow cathode; connecting the first and second electrodes to high voltage; introducing a discharge gas through the hollow cathode to provide a gas fill between the first and second electrodes in an area of the electrode recesses, wherein the gas fill has a predetermined gas pressure in accordance with a discharge operation realized on a left branch of the Paschen curve; generating in front of the hollow cathode from the discharge gas exiting from the hollow cathode a plasma emitting the radiation when supplying high voltage; displacing or deforming the plasma by providing a pressure gradient of the gas fill in front of the hollow cathode.