引力波探测中惯性传感器的残余气体动力学特性机理研究

Study on Physical Mechanisms of Dynamical Characteristics of Residual Gases in Inertial Sensors Applied into Gravitational Wave Detection

作为空间引力波探测的核心系统,惯性传感器在轨运行时的噪声干扰诱发机制解析是迫切需要解决的关键科学问题。惯性传感器中检验质量(TM)的残余加速度噪声是限制探测器灵敏度的最大噪声源。作为残余气体噪声的直接表征手段,惯性传感器复杂拓扑构型下气体分子逃逸时间动态特性解析亟待解决。文章首先考虑了狭小空间下检验质量块与周围壁面间的材料属性、放气特性等差异性,建立了异质空间复杂拓扑结构下的惯性传感器数理模型;其次解析出残余气体噪声与气体分子逃逸时间之间的定量约束关系,提取了逃逸时间核心影响因素;随后以蒙特卡洛模拟技术为切入点,得到约束条件下气体分子从板间扩散出去所需的逃逸时间及碰撞次数的模拟解。文章研究发现:不同气体成分、壁面性质对残余气体噪声有较大影响;考虑气体分子在壁面的滞留时间会大幅增加逃逸时间、降低碰撞频率。

As the core system for gravitational wave detection in space,the analysis of the noise interference inducing mechanism of inertial sensors during in-orbit operation is a key scientific problem that needs to be solved urgently.The residual acceleration noise of the test mass(TM)in the inertial sensor is the largest noise source limiting the sensitivity of the detector.As a direct characterization of the residual gas noise,the analysis of the escape time dynamics of gas molecules under the complex topological configuration of inertial sensors needs to be solved urgently.In this paper,we firstly consider the differences in material properties and outgassing characteristics between the test mass block and the surrounding wall in a narrow space,and establish a mathematical model of inertial sensors under the complex topology of heterogeneous space;secondly,we analyze the quantitative constraints between the residual gas noise and escape time of gas molecules,and extract the core factors affecting the escape time;subsequently,we use Monte Carlo simulation as the entry point to obtain the dynamic characteristics of gas molecules diffusing out from the plate under the constraints,and then we use Monte Carlo simulation as the entry point for the analysis.Subsequently,Monte Carlo simulation technique is used as an entry point to obtain the simulation solutions for the escape time and the number of collisions required for the gas molecules to diffuse out from the plate.This paper finds that:different gas compositions and wall properties have a large impact on the residual gas noise;considering the retention time of gas molecules on the wall will substantially increase the escape time and decrease the collision frequency.