Abstract: A measuring device for determining contamination of a surface of a component in an lithographic projection apparatus. The measuring device includes a radiation transmitter for transmitting radiation on at least a part of the surface and a radiation receiver for receiving radiation from the component. A processor is communicatively connected to the receiver, for deriving a property of received radiation and deriving a property of the contamination from the property of received radiation.

Abstract: A radiation source comprises an anode and a cathode that are configured and arranged to create a discharge in a gas or vapor in a space between anode and cathode and to form a plasma pinch so as to generate electromagnetic radiation. The gas or vapor may comprise xenon, indium, lithium and/or tin. The radiation source may comprise a plurality of discharge elements, each of which is only used for short intervals, after which another discharge element is selected. The radiation source may also comprise a triggering device, which device can facilitate improving the exact timing of the pinch formation and thus the pulse of EUV radiation. The radiation source may also be constructed to have a low inductance, and operated in a self-triggering regime.