Patent ID: 6963595

Claim:
A very narrow band high repetition rate gas discharge laser system comprising: A) a discharge chamber containing; a) a first laser gas and b) a first pair of elongated spaced apart electrodes defining a first discharge region, c) a first fan for producing sufficient gas velocities of said first laser gas in said first discharge region to clear from said first discharge region, following each pulse, substantially all discharge produced ions prior to a next pulse when operating at a repetition rate in the range of 4,000 pulses per second or greater, d) a first heat exchanger system capable of removing heat energy from said first laser gas, B) a line narrowing unit for narrowing spectral bandwidths of light pulses produced in said first discharge chamber; C) a pulse power system configured to provide electrical pulses to said first pair of electrodes sufficient to produce laser pulses at rates of about 4,000 pulses per second or greater with precisely controlled pulse energies in excess of about 5 mJ; D) a fluorine injection system for maintaining, within desired ranges, a fluorine gas concentration contained in said discharge chamber; said injection system comprising one or more processors programmed with an algorithm for monitoring the change in laser output light pulses energy for a change in the voltage applied across said electrodes (“ΔE/ΔV”) decrease during operation of the laser system and monitoring the ΔE/ΔV increase as a result of an F 2 injection of a known quantity of F 2 ; E) a laser beam measurement and control system for measuring pulse energy, wavelength and bandwidth of laser output pulses produced by said two chamber laser system and controlling said laser output pulses in a feedback control arrangement.