Target area structural design of ShenGuangIII

This paper will present a summary of the target area structural design results of ShenGuangIII (SGIII), which includes target bay and switchyard support structures, target chamber, and beam transport system. The target area building is rectangular and includes a target bay and a switchyard. The outer wall of the target area building is based outside the vibration isolation trenches and separates the diurnal temperature loads and the wind loads that occur outside the target area building during the alignment process prior to a shot. The target bay and switchyard support structures are mainly comprised of the steel reinforced concrete building and the steel space frame. The target chamber is a welded sphere made of aluminum alloy 5052 and has an inner diameter of 6 m and a nominal wall thickness of 8 cm. The beam transport system brought the 48 laser beams to the final optics assemblies (FOAs) and includes 276 transport mirrors. Sources that influence stability are mainly ambient random vibration, ambient wind induced vibrations, diurnal temperature changes, and HVAC. A FEM is used to calculate the responses of the target area structure under broadband ambient random vibration. The position deviations of 48 beam lines are calculated and used to evaluate the stability of the target area structure. The analyses demonstrated that the positioning deviations of 48 beam lines satisfy the deviation budget requirements.