METHOD AND APPARATUS FOR THE GENERATION OF SHORT-WAVELENGTH RADIATION BY MEANS OF A GAS DISCHARGE-BASED HIGH-FREQUENCY, HIGH-CURRENT DISCHARGE.

摘要

The invention is related to a gas discharge-based radiation source which emits short-wavelength radiation, wherein an emitter is ionized and compressed by pulse-shaped currents between two electrodes arranged in a vacuum chamber and is excited to form an emitting plasma. According to the invention, the plasma is preserved by means of a high-frequency sequence of pulse-shaped currents the pulse repetition period of which is adjusted so as to be shorter than a lifetime 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. For exciting the relaxing plasma to the compressed plasma, excitation energy is coupled into the relaxing plasma by making use of pulse-shaped currents with repetition frequencies between 50 kHz and 4 MHz and pulse widths equal to the pulse repetition period.