Patent ID: 8610354

Claim:
A method for excitation of a gas discharge-based radiation source emitting short-wavelength radiation, comprising: ionizing an emitter by means of pulse-shaped currents between two electrodes arranged in a vacuum chamber, and further excitation by periodical compression to form a pulsed emitting plasma emitting the desired short-wavelength radiation by each pulse over an emission duration; maintaining the plasma uninterruptedly by means of a high-frequency sequence of pulse-shaped currents by setting a pulse repetition period of the pulse-shaped currents which is shorter than a lifetime of the plasma corresponding to a duration of presence of the plasma so that the plasma is kept periodically alternating between a high-energy state of an emitting compressed plasma and a low-energy state of a relaxing plasma, and coupling excitation energy into the relaxing plasma for an excitation of the relaxing plasma to generate the emitting compressed plasma, wherein the pulse-shaped currents are generated with a pulse repetition frequency (f) in the range between 50 kHz and 4 MHz and with a pulse width which is equal to the period of pulse repetition frequency (f).