Conceptual design of a KrF scaling module. Final report

A conceptual design of an angular multiplexed 50 kJ KrF laser module for Inertial Confinement Fusion is presented. Optical designs for encoding, beam packing and beam transfer between amplifier stages are developed; emphasis is 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 alignment. A kinetic code model was developed for the KrF amplifier and was used to derive scaling maps for the 50 kJ module. Attention was given to reducing parasitics, achieving acceptable extraction efficiency and accounting for amplified spontaneous emission effects. The size of the module is constrained by parasitic suppression and damage thresholds; the power gain is constrained by demanding 40% extraction efficiency in a double pass extraction geometry; and, the run time is constrained by the pulsed power technology (PFN or PFL) and acceptable values of g0L. The bounds imposed on the design by the pulsed power technology were examined. Both PFLs and PFNs were considered along with their associated diode, hibachi and guide field requirements. A base line design for a 50 kJ module including amplifier staging, layout and overall size is discussed. Cost analysis and scaling for optical components, pulsed power technology and the guide field are also presented