前置平面镜热负载对变包含角平面光栅单色器分辨率的影响

针对变包含角平面光栅单色器前置平面镜（PM）受热负载而导致的单色器分辨率降低问题，提出优化聚焦常数（C_ff）补偿分辨率的方法。首先，计算不同C_ff值时PM的热功率吸收谱，在此基础上对镜面热负载进行热-结构耦合分析，得到不同热负载时PM表面热变形的变化量；然后，结合理想分辨率公式和光线追迹软件求出加热负载的单色器分辨率；最后，优化C_ff实现分辨率的补偿。研究结果表明，以软X射线谱学显微光束线站为例，当出射光能量为1 000 eV时，将C_ff由1.8优化至1.84，单色器分辨率即可与无热负载时的相同，该优化方法可有效补偿单色器分辨率的降低。

Effects of plane mirror thermal load on variable included angle plane-grating monochromator resolution

In synchrotron radiation beamlines , the increasing light flux will lead to more thermal load on opti-cal elements .The thermal load on the Plane Mirror （ PM） of variable included angle plane-grating monochrom-ator will decrease the resolution .This paper proposes a method to recover the resolution by optimizing the val-ue of focusing constant（Cf ）.Firstly, the absorption spectra of thermal power with different values of Cf are obtained by calculation .Then thermo-mechanical analysis of PM is conducted to get variable deformations on PM with different thermal power .Secondly , the resolution is calculated by combining the function of ideal res-olution and the software of ray tracing .Finally, the resolution is compensated by optimizing Cf .The result in-dicates that taking the soft X-ray spectroscopy micro beam line station of SSRF for example , the resolution can be improved by changing the value of Cf from 1.8 to 1.84 when the photon energy is 1 000 eV.So optimizing＆amp;nbsp;the value of Cf is an effective way to recover the decreased resolution induced by thermal power on PM .