ICF装置光束定位的结构稳定性设计

Structure stability design of beam positioning in ICF facility

激光驱动ICF装置的甚多束激光在打靶过程中需要高精度定位于靶面,这就要求可以改变光束着靶点位置的光学元件满足定位误差指标要求。首先介绍光束定位误差分解方法,在光束对准过程中和打靶前,在多源激励作用下能改变光束着靶点位置的光学元件需要评估其支撑系统的稳定性设计,发展了光学元件稳定性指标分解方法用于其支撑系统的稳定性评估。从基频、环境随机振动、模态阻尼的角度讨论了支撑系统振动稳定性设计思路。光学元件的通用支撑系统采用大而重的钢筋混凝土和钢结构的混合结构,钢筋混凝土保证光学元件稳定性的同时,钢结构提供结构设计的灵活性。采用有限元技术分析光学元件在宽频环境随机振动作用下的响应,评估支撑系统的振动稳定性设计。描述了神光III宽频环境随机振动和光束定位误差的测量,测量结果表明神光III支撑系统满足设计要求,该技术能应用于激光驱动ICF装置支撑系统的设计。

Within ICF laser system, many independent laser beams are required to be positioned on target with a very high degree of accuracy during a shot. Optical elements that are capable of moving a laser beam on the target must meet the pointing error budgets. The beam positioning error budgeting was provided. The stability allocation was developed for evaluating the performance of support systems when they were subjected to multiple sources of excitation that can cause motions of optical elements during the alignment procedure and before a shot. The vibrational stability design considerations of support systems on the fundamental frequency, ambient random vibration, and modal damping was discussed. The superstructures of optical elements were the relatively large and massive hybrid structure of reinforced concretes and steel frames or vessels. While the reinforced concrete portions provided optical elements stability, the steel portions afforded design flexibility. Finite element analyses of response of broadband ambient random vibration were performed to evaluate the vibrational stability design of support systems.Measurement on broadband ambient random vibration and beam positioning error in target area of SGIIIwas described. The measurement result show that its support systems meet the design requirements and these information can be used on similar ICF laser system.