Conceptual design of an angular multiplexed 50 kJ KrF amplifier for ICF

Abstract

A conceptual design of an angular multiplexed 50 kJ KrF laser module is presented for use as a reactor driver for inertial confinement fusion (ICF). Such multiplexing is one approach to achieve the pulse compression needed for an efficient reactor driver. Optical designs are developed with emphasis placed on reducing prepulse problems and achieving acceptable optical quality. An axisymmetric optical design is identified as optimum in terms of simplicity, optical quality, cost, and ease of alignment. A kinetic code model for the KrF amplifier was used to derive scaling maps for the 50 kJ module with acceptable extraction efficiency and accounting for amplified spontaneous emission effects. The size of the module is constrained by parasitic suppression and damage threshold; the power gain is constrained by demanding 40 percent extraction efficiency in a double-pass extraction geometry, and the run time is constrained by the pulsed power technology and acceptable values of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">g_{0}L</tex> . The bounds imposed on the design by the pulsed power technology were examined.