Zhang Ling, Morita Shigeru, Xu Zong, Wu Zhenwei, Zhang Pengfei, Wu Chengrui, Gao Wei, Ohishi Tetsutarou, Goto Motoshi, Shen Junsong, Chen Yingjie, Liu Xiang, Wang Yumin, Dong Chunfeng, Zhang Hongmin, Huang Xianli, Gong Xianzu, Hu Liqun, Chen Junlin, Zhang Xiaodong, Wan Baonian, Li Jiangang
Institute of Plasma Physics Chinese Academy of Sciences, Hefei 230026, Anhui, China.
National Institute for Fusion Science, Toki 509-5292, Gifu, Japan.
Rev Sci Instrum. 2015 Dec;86(12):123509. doi: 10.1063/1.4937723.
A flat-field extreme ultraviolet (EUV) spectrometer working in the 20-500 Å wavelength range with fast time response has been newly developed to measure line emissions from highly ionized tungsten in the Experimental Advanced Superconducting Tokamak (EAST) with a tungsten divertor, while the monitoring of light and medium impurities is also an aim in the present development. A flat-field focal plane for spectral image detection is made by a laminar-type varied-line-spacing concave holographic grating with an angle of incidence of 87°. A back-illuminated charge-coupled device (CCD) with a total size of 26.6 × 6.6 mm(2) and pixel numbers of 1024 × 255 (26 × 26 μm(2)/pixel) is used for recording the focal image of spectral lines. An excellent spectral resolution of Δλ0 = 3-4 pixels, where Δλ0 is defined as full width at the foot position of a spectral line, is obtained at the 80-400 Å wavelength range after careful adjustment of the grating and CCD positions. The high signal readout rate of the CCD can improve the temporal resolution of time-resolved spectra when the CCD is operated in the full vertical binning mode. It is usually operated at 5 ms per frame. If the vertical size of the CCD is reduced with a narrow slit, the time response becomes faster. The high-time response in the spectral measurement therefore makes possible a variety of spectroscopic studies, e.g., impurity behavior in long pulse discharges with edge-localized mode bursts. An absolute intensity calibration of the EUV spectrometer is also carried out with a technique using the EUV bremsstrahlung continuum at 20-150 Å for quantitative data analysis. Thus, the high-time resolution tungsten spectra have been successfully observed with good spectral resolution using the present EUV spectrometer system. Typical tungsten spectra in the EUV wavelength range observed from EAST discharges are presented with absolute intensity and spectral identification.
一种新型的平场极紫外（EUV）光谱仪已被开发出来，它工作在20 - 500 Å波长范围内，具有快速的时间响应，用于测量带有钨偏滤器的实验先进超导托卡马克（EAST）中高电离态钨的谱线发射，同时监测轻杂质和中等杂质也是当前开发的一个目标。用于光谱图像检测的平场焦平面由层状变线间距凹面全息光栅制成，入射角为87°。使用一个总尺寸为26.6×6.6 mm²、像素数为1024×255（26×26 μm²/像素）的背照式电荷耦合器件（CCD）来记录谱线的焦平面图像。在仔细调整光栅和CCD位置后，在80 - 400 Å波长范围内获得了出色的光谱分辨率Δλ0 = 3 - 4像素，其中Δλ0定义为谱线足部位置的半高宽。当CCD以全垂直合并模式运行时，其高信号读出速率可以提高时间分辨光谱的时间分辨率。它通常以每帧5 ms的速度运行。如果通过窄缝减小CCD的垂直尺寸，时间响应会变得更快。因此，光谱测量中的高时间响应使得各种光谱研究成为可能，例如，在具有边缘局域模爆发的长脉冲放电中的杂质行为研究。还使用在20 - 150 Å的EUV轫致辐射连续谱技术对EUV光谱仪进行了绝对强度校准，以进行定量数据分析。因此，使用当前的EUV光谱仪系统成功地以良好的光谱分辨率观测到了高时间分辨率的钨光谱。给出了从EAST放电中观测到的EUV波长范围内典型的钨光谱，并带有绝对强度和光谱标识。
