A Magnetohydrodynamic System for Pumping Liquid Metal Media in a Plasma Source of Extreme Ultraviolet Radiation

A sealed compact system based on two series-connected magnetohydrodynamic pumps for pumping liquid metal media with an operating temperature as high as 450°C is described. The system is designed to produce a renewable target in the form of a liquid lithium jet in a pulsed-repetition rate source of extreme ultraviolet (EUV) radiation based on laser plasma. The system provides a head pressure of 2 bar and a flow rate of up to 80 cm3/s and is characterized by reliability, simplicity of design, the absence of moving parts, convenient handling, and the ability to pump aggressive conductive liquids. The system is easily scalable in both the head pressure and the flow rate. The long-term operation of the system has been demonstrated in a laser-produced plasma EUV source, where it provided a jet velocity of up to 22 m/s.