RADIATION SOURCE AND LITHOGRAPIC APPARATUS

摘要

The present invention provides methods and apparatus for facilitating the start up of a fuel droplet stream generator. During a start-up phase the fuel droplet stream generator is positioned so that the fuel droplets re emitted downwardly whereby gravity assists in the establishment of the stream. The droplets are monitored using a visualization system and once the stream is determined to have the desired characteristics the stream generator is moved to a second position of steady state use in which the droplet stream is emitted in a horizontal direction.