To reduce arcing generation and nozzle erosion in a laser plasma extreme ultra violet radiation source.

One or more solutions are used for preventing materials of a nozzle assembly 40 of the radiation source 10 from being evaporated by an electrical discharge form a plasma 30. A first solution includes utilization of an electrically insulated nozzle end such as a glass capillary tube 46. The tube 46 is elongated beyond all conductive surface of the nozzle assembly 40 by an appropriate distance so that a pressure around the conductive portion of the nozzle assembly 40 closest to the plasma 30 can be lowered so as not to induce an arc discharge. A second solution includes electrically insulating the conductive portion of the radiation source 10 from a vacuum chamber wall. A third solution includes increasing a potential of the nozzle assembly 40 to that of the arc by applying a bias voltage 52 to the nozzle assembly 40.