An extreme ultraviolet radiation generator is disclosed in which Xenon gas is continuously ejected from a high pressure nozzle into a low pressure chamber to generate Xenon atom clusters which are irradiated with a high repetition rate pulsed laser to form a plasma and yield quasi-continuous EUV generation. The nozzle has a beveled outer rim to enable the focus point of the laser light to be brought close to the nozzle. The nozzle is cooled to a temperature at which background Xenon gas condenses onto the nozzle forming a protective layer. A gas compressor serves to recirculate the Xenon gas and batch purification triggered by a mass spectrometer monitoring gas purity may be periodically applied.