Final Optic Protection Designs for ICF Containment Chambers*

Thegeometrical layout for the 68 beams of the 10 megajoule laser shows the final optics placed at 25 meters from the target (see Fig. 1). The final optic will be a 2–5 cm thick debris shield ($40K each) which will be placed in front of a $200K focussing lens. Each of the 68 beams will deliver 150 kJ of 0.35 µm (3ω) light and will consist of either a 4×4 or a 2×8 array of beamlets, with each beamlet aperture having dimensions of 29 cm × 29 cm. This produces a 3ω energy density at the final optic of 12 J/cm² average and 225-30 J/cm² peak.