Yang Fangchao, Bai Yanzheng, Hong Wei, Sumner Timothy J, Zhou Zebing
MOE Key Laboratory of Fundamental Physical Quantities Measurement, Hubei Key Laboratory of Gravitation and Quantum Physics, PGMF and School of Physics, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China.
Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom.
Rev Sci Instrum. 2020 Dec 1;91(12):124502. doi: 10.1063/5.0013232.
Various space missions and applications require the charge on isolated test masses to be strictly controlled because any unwanted disturbances will introduce acceleration through the Coulomb interaction between the test masses and their surrounding conducting surfaces. In many space missions, charge control has been realized using ultraviolet (UV) photoemission to generate photoelectrons from metal surfaces. The efficiency of photoelectron emission strongly depends on multiple physical parameters of gold-coated surfaces, such as the work function, reflectivity, and quantum yield. Therefore, to achieve satisfactory charge control performance, these parameters need to be measured accurately. This paper describes a charge control method that achieves self-adaptive charge neutralization while removing the need to measure the above-mentioned physical parameters. First, to explain the principle, a differential illumination model is constructed based on the typical structure of an inertial sensor. A charge management system based on a torsion pendulum system is then introduced along with an UV light emitting diode coupling system. Finally, experimental results are obtained in a vacuum chamber system with a pressure of 10 mbar, showing that precise calibration allows the test mass potential to be automatically controlled below 10 mV without considering the physical parameters or measuring the potential of the test mass before or after the control process.
各种太空任务和应用都要求严格控制孤立测试质量块上的电荷，因为任何不必要的干扰都会通过测试质量块与其周围导电表面之间的库仑相互作用引入加速度。在许多太空任务中，电荷控制是通过紫外线（UV）光发射从金属表面产生光电子来实现的。光电子发射效率强烈依赖于镀金表面的多个物理参数，如功函数、反射率和量子产率。因此，为了实现令人满意的电荷控制性能，需要精确测量这些参数。本文描述了一种电荷控制方法，该方法在无需测量上述物理参数的情况下实现自适应电荷中和。首先，为了解释原理，基于惯性传感器的典型结构构建了一个差分照明模型。然后介绍了基于扭摆系统的电荷管理系统以及紫外线发光二极管耦合系统。最后，在压力为10毫巴的真空室系统中获得了实验结果，结果表明精确校准可以在不考虑物理参数或在控制过程之前或之后测量测试质量块电势的情况下，将测试质量块电势自动控制在10毫伏以下。
