A UV preionized, high‐purity construction, closed‐cycle‐flow rare‐gas‐halide laser has been constructed to study laser characteristics at high pulse repetition frequency and closed cycle behavior of the laser chemistry. Operating characteristics of the laser with ArF, KrF, XeF, and XeCl have been obtained. The XeCl laser has demonstrated the best performance, yielding a maximum average power of 45 W at 600 Hz and greater than 35 W at 500 Hz for 1 h.