近地空间下X/EUV透射光栅的热力学有限元分析

为了实现极紫外透射光栅光谱仪在近地空间的应用,针对其核心色散元件2000线/毫米X/EUV透射光栅,本文采用有限元方法建立了机械模型并对其热学性能和耦合特性进行计算机模拟计算,通过模拟热膨胀系数不同的材料构成的薄膜光栅在近地空间受到太阳辐照后的温度场,得到该光栅表面的热形变分布.结果表明,在高真空热环境下,该透射光栅表面形变量平均可达0.56μm,而影响光栅周期的纵向形变平均值则为71.5 nm.由于热形变会对光栅衍射效率产生重要影响并导致光谱仪精度和性能的下降,利用有限元分析模拟的结果,进一步优化光栅的封装和设计制作,使其栅线处纵向热形变趋近于零,为2000线/毫米X/EUV透射光栅在太阳极紫外辐射探测器上得到应用提供了科学依据和有效支持.

Thermodynamics Finite Element Analysis of X/EUV Transmission Grating in Terrestrial Space

In order to meet the requirement of Extreme Ultraviolet(EUV)transmission grating spectrometer in terrestrial space,thermal and mechanical properties of 2000 1/mm X/EUV transmission grating was investigated by means of simulation method.The mechanistic model was established and its thermal and coupling properties were simulated using the method of finite element analysis.Moreover,the distributions of thermal field and thermal deformation were obtained based on transmission grating consisting of different materials with different thermal expansion coefficients.The results are shown that the surface deformation of transmission grating is 0.56 μm as well as the longitudinal deformation value is 71.5 nm(average value).Due to thermal deformation,the diffraction efficiency and precision of spectrograph decline.In terms of simulation results,the package and structure of grating were optimized for applications in solar EUV radiation spectroscopies.