一种用于实时霍尔推力器侵蚀测量的光腔衰荡光谱传感器。

A cavity ring-down spectroscopy sensor for real-time Hall thruster erosion measurements.

作者信息

Lee B C, Huang W, Tao L, Yamamoto N, Gallimore A D, Yalin A P

机构信息

Physics Department, Colorado State University, Fort Collins, Colorado 80521, USA.

NASA Glenn Research Center, 2100 Brookpark Rd., Cleveland, Ohio 44135, USA.

出版信息

Rev Sci Instrum. 2014 May;85(5):053111. doi: 10.1063/1.4879135.

DOI:10.1063/1.4879135

PMID:24880357

Abstract

A continuous-wave cavity ring-down spectroscopy sensor for real-time measurements of sputtered boron from Hall thrusters has been developed. The sensor uses a continuous-wave frequency-quadrupled diode laser at 250 nm to probe ground state atomic boron sputtered from the boron nitride insulating channel. Validation results from a controlled setup using an ion beam and target showed good agreement with a simple finite-element model. Application of the sensor for measurements of two Hall thrusters, the H6 and SPT-70, is described. The H6 was tested at power levels ranging from 1.5 to 10 kW. Peak boron densities of 10 ± 2 × 10(14) m(-3) were measured in the thruster plume, and the estimated eroded channel volume agreed within a factor of 2 of profilometry. The SPT-70 was tested at 600 and 660 W, yielding peak boron densities of 7.2 ± 1.1 × 10(14) m(-3), and the estimated erosion rate agreed within ~20% of profilometry. Technical challenges associated with operating a high-finesse cavity in the presence of energetic plasma are also discussed.

摘要

已开发出一种用于实时测量霍尔推力器溅射硼的连续波腔衰荡光谱传感器。该传感器使用波长为250 nm的连续波四倍频二极管激光器来探测从氮化硼绝缘通道溅射出来的基态原子硼。使用离子束和靶材的受控装置的验证结果与一个简单的有限元模型显示出良好的一致性。描述了该传感器在两台霍尔推力器H6和SPT - 70测量中的应用。H6在1.5至10 kW的功率水平下进行了测试。在推力器羽流中测得的硼峰值密度为10±2×10(14) m(-3)，并且估计的侵蚀通道体积与轮廓测量法的结果在2倍范围内相符。SPT - 70在600和660 W下进行了测试，产生的硼峰值密度为7.2±1.1×10(14) m(-3)，并且估计的侵蚀速率与轮廓测量法的结果在约20%的范围内相符。还讨论了在高能等离子体存在的情况下操作高精细度腔所面临的技术挑战。