The design, construction and testing of the X-ray laser project krypton-fluoride laser amplifier

A large, UV preionized excimer krypton-fluoride (KrF) laser amplifier was designed and fabricated. This laser amplifier produced an on-target laser power density of 2*10/sup 18/ W/cm/sup 2/. Maximum output energy was determined to be 5 J in a 20-ns-long pulse, and maximum instantaneous power was achieved in a 250-350-mJ, 300-fs pulse with an injection (seed) pulse of approximately=3-4 mJ in a triple pass configuration. The output wavelength is 248 nm. The amplifier has a volume of approximately 5 liters. UV preionization was accomplished with a traveling spark board. Fast, low inductance switching of the high voltage was accomplished through the use of an electrically triggered rail-gap. Some of the design and tradeoffs of the electrical pulse discharge circuitry, considerations related to the materials used, the optics, gas handling, timing requirements, and some experimental results are discussed. >