Arrangement for the optical detection of a moving target flow for a pulsed energy beam pumped radiation

An arrangement for the optical detection of a moving target flow for pulsed energy beam pumped radiation generation based on a plasma in which a target generator is provided for generating a target flow advancing along a path and an energy beam for plasma generation is directed to a defined interaction point of the path of the target flow, this interaction point being located in a vacuum chamber for plasma generation, comprising:

• said target generator providing a target flow of moving material with relatively constant target states in the interaction point;
• said target flow having, at least in a recurring manner over time, identical conditions for the generation of plasma for radiation emission;
• a sensor unit being provided for observation of the position of the target flow at a detection point which lies at a short distance from the interaction point on the path;
• said sensor unit being provided for illuminating the target flow moving past with transmission light and for receiving proportions of the transmission light that are reflected at a portion of the illuminated target flow;
• said sensor unit containing a detection module and a projection module, wherein the projection module having means for focusing the transmission light onto the detection point in the target flow, so that portions of transmission light are reflected from target material passing the detection point, and said reflected portions of the transmission light being received once more by said focusing means and said projection module and directed to said detection module;
• and
• a light waveguide being provided between the detection module and projection module for transmitting transmission light and optical signals resulting from reflected portions of the transmission light at the target flow passing the detection point.