Li Changjun, Brezinsek Sebastijan, Ertmer Stephan, Kreter Arkadi, Reinhart Michael, Ding Rui, Chen Junling
Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, People's Republic of China.
Forschungszentrum Jülich GmbH-Institut für Energie- und Klimaforschung-Plasmaphysik, Partner of the Trilateral Euregio Cluster (TEC), 52425 Jülich, Germany.
Rev Sci Instrum. 2023 Aug 1;94(8). doi: 10.1063/5.0155722.
A hyperspectral camera (HSC-type Specim IQ) has been applied at the linear plasma device PSI-2 under steady-state conditions. The camera has the capacity of hyperspectral imaging (HSI) with the dimension of a data array 512 × 512 × 204 (x, y, λ) covering the spectral span from 400 to 1000 nm with moderate average spectral resolution (FWHM ∼7 nm). After radiometric calibration and background/continuum emission subtraction, two main applications of the camera, (i) plasma diagnostics in helium (He) plasmas and (ii) plasma-material interaction studies with tungsten (W) targets in neon (Ne) plasmas, have been carried out. The measurements were complemented by a movable Langmuir double probe system (LP) measuring electron temperature (Te) and electron density (ne) in radial direction r and a fiber-coupled cross-dispersion spectrometer with high spectral resolution (Spectrelle) recording neutral He, W, and Ne emission lines over the full plasma column. (i) Two-dimensional (2D) imaging of Te and ne radial profiles in axial direction z of the He plasma column were for the first time obtained by the regression analysis of Te and ne (from LP) and six He I line ratios (from HSC). The spatially resolved plasma parameters covered in these studies range between Te ∼ 0.8-13.4 eV and ne ∼ 0.2 × 1018-3.9 × 1018 m-3 and permit a reconstruction of the plasma conditions in PSI-2 in 2D without LP perturbation. (ii) W sputtering was studied in situ in Ne plasmas exposing W target samples (negatively biased at 100 V) under perpendicular Ne plasma impact. Simultaneously, the 2D distributions of W (W I line at 429.5 nm) in front of the target and the 2D Ne plasma distribution (Ne I line at 703.2 nm) were recorded with complete spectral separation as confirmed by the Spectrelle spectrometer. This permits the simultaneous measurement of the neutral W penetration and its angular distribution induced in the sputtering process and of the impinging plasma distribution. The HSI technique offers, despite a few technical drawbacks, such as the moderate spectral resolution and poor time resolution, a new possibility to distinguish multiple emission lines from plasma and impurities and complements the portfolio of existing Optical Emission Spectroscopy techniques, providing a good compromise regarding spectral, spatial, and temporal resolution.
一台高光谱相机（HSC型Specim IQ）已应用于稳态条件下的线性等离子体装置PSI-2。该相机具备高光谱成像（HSI）能力，数据阵列维度为512×512×204（x、y、λ），覆盖400至1000纳米的光谱范围，平均光谱分辨率适中（半高宽约7纳米）。在进行辐射校准和背景/连续发射扣除后，开展了该相机的两项主要应用：（i）氦（He）等离子体中的等离子体诊断；（ii）氖（Ne）等离子体中钨（W）靶材的等离子体-材料相互作用研究。测量工作由一个可移动的朗缪尔双探针系统（LP）辅助进行，该系统在径向r测量电子温度（Te）和电子密度（ne），还有一台具有高光谱分辨率的光纤耦合交叉色散光谱仪（Spectrelle）记录整个等离子体柱上的中性He、W和Ne发射线。（i）通过对Te和ne（来自LP）以及六条He I线比值（来自HSC）进行回归分析，首次获得了He等离子体柱轴向z方向上Te和ne径向分布的二维（2D）成像。这些研究中涵盖的空间分辨等离子体参数范围为Te约0.8 - 13.4电子伏特，ne约0.2×10^18 - 3.9×10^18立方米^-3，并且能够在无LP扰动的情况下二维重建PSI-2中的等离子体条件。（ii）在垂直Ne等离子体冲击下，对暴露于W靶材样品（负偏压100伏）的Ne等离子体中的W溅射进行了原位研究。同时，用Spectrelle光谱仪证实，以完全的光谱分离记录了靶材前方W（429.5纳米处的W I线）的二维分布和Ne等离子体的二维分布（703.2纳米处的Ne I线）。这使得能够同时测量溅射过程中诱导的中性W渗透及其角分布以及入射等离子体分布。尽管高光谱成像（HSI）技术存在一些技术缺陷，如中等光谱分辨率和较差的时间分辨率，但它为区分来自等离子体和杂质的多条发射线提供了新的可能性，补充了现有发射光谱技术的组合，在光谱、空间和时间分辨率方面实现了良好的折衷。
