A grazing incidence flat-field spectrograph using a concave grating was constructed to measure extreme ultraviolet （EUV） emission from a CO 2 laser-produced tin plasma throughout the wavelength region of 5 nm to 20 ...A grazing incidence flat-field spectrograph using a concave grating was constructed to measure extreme ultraviolet （EUV） emission from a CO 2 laser-produced tin plasma throughout the wavelength region of 5 nm to 20 nm for lithography. Spectral efficiency of the EUV emission around 13.5 nm from plate, cavity, and thin foil tin targets was studied. By translating the focusing lens along the laser axis, the dependence of EUV spectra on the amount of defocus was investigated. The results showed that the spectral efficiency was higher for the cavity target in comparison to the plate or foil target, while it decreased with an increase in the defocus distance. The source＇s spectra and the EUV emission intensity normalized to the incident pulse energy at 45 from the target normal were characterized for the in-band （2% of bandwidth） region as a function of laser energy spanning from 46 mJ to 600 mJ for the pure tin plate target. The energy normalized EUV emission was found to increase with the increasing incident pulse energy. It reached the optimum value for the laser energy of around 343 mJ, after which it dropped rapidly.展开更多
An impurity powder dropper was installed in the 21 st campaign of the Large Helical Device experiment(Oct.2019–Feb.2020)under a collaboration between the National Institute for Fusion Science and the Princeton Plasma...An impurity powder dropper was installed in the 21 st campaign of the Large Helical Device experiment(Oct.2019–Feb.2020)under a collaboration between the National Institute for Fusion Science and the Princeton Plasma Physics Laboratory for the purposes of real-time wall conditioning and edge plasma control.In order to assess the effective injection of the impurity powders,spectroscopic diagnostics were applied to observe line emission from the injected impurity.Thus,extreme-ultraviolet(EUV)and vacuum-ultraviolet(VUV)emission spectra were analyzed to summarize observable impurity lines with B and BN powder injection.Emission lines released from B and N ions were identified in the EUV wavelength range of 5–300Ameasured using two grazing incidence flat-field EUV spectrometers and in the VUV wavelength range of 300–2400Ameasured using three normal incidence 20 cm VUV spectrometers.BI–BV and NIII–NVII emission lines were identified in the discharges with the B and BN powder injection,respectively.Useful B and N emission lines which have large intensities and are isolated from other lines were successfully identified as follows:BI(1825.89,1826.40)A(blended),BII 1362.46A,BIII(677.00,677.14,677.16)A(blended),BIV 60.31A,BV 48.59A,NIII(989.79,991.51,991.58)A(blended),NIV765.15A,NV(209.27,209.31)A(blended),NVI 1896.80A,and NVII 24.78A.Applications of the line identifications to the advanced spectroscopic diagnostics were demonstrated,such as the vertical profile measurements for the BV and NVII lines using a space-resolved EUV spectrometer and the ion temperature measurement for the BII line using a normal incidence 3 m VUV spectrometer.展开更多
基金supported by the Scientific Research Foundation of the Education Department of Hubei Province (No.Q20131512)National Natural Science Foundation of China (No.61078024)
文摘A grazing incidence flat-field spectrograph using a concave grating was constructed to measure extreme ultraviolet （EUV） emission from a CO 2 laser-produced tin plasma throughout the wavelength region of 5 nm to 20 nm for lithography. Spectral efficiency of the EUV emission around 13.5 nm from plate, cavity, and thin foil tin targets was studied. By translating the focusing lens along the laser axis, the dependence of EUV spectra on the amount of defocus was investigated. The results showed that the spectral efficiency was higher for the cavity target in comparison to the plate or foil target, while it decreased with an increase in the defocus distance. The source＇s spectra and the EUV emission intensity normalized to the incident pulse energy at 45 from the target normal were characterized for the in-band （2% of bandwidth） region as a function of laser energy spanning from 46 mJ to 600 mJ for the pure tin plate target. The energy normalized EUV emission was found to increase with the increasing incident pulse energy. It reached the optimum value for the laser energy of around 343 mJ, after which it dropped rapidly.
基金supported by the Post-CUP programJSPSCAS Bilateral Joint Research Projects,‘Control of wall recycling on metallic plasma facing materials in fusionreactor,’2019–2022,(No.GJHZ201984)+2 种基金US Department of Energy(No.DE-AC02-09CH11466)with Princeton Universitythe LHD project financial support(Nos.ULPP010,ULFF022)JSPS KAKENHI(Nos.17K14426,20K03896)。
文摘An impurity powder dropper was installed in the 21 st campaign of the Large Helical Device experiment(Oct.2019–Feb.2020)under a collaboration between the National Institute for Fusion Science and the Princeton Plasma Physics Laboratory for the purposes of real-time wall conditioning and edge plasma control.In order to assess the effective injection of the impurity powders,spectroscopic diagnostics were applied to observe line emission from the injected impurity.Thus,extreme-ultraviolet(EUV)and vacuum-ultraviolet(VUV)emission spectra were analyzed to summarize observable impurity lines with B and BN powder injection.Emission lines released from B and N ions were identified in the EUV wavelength range of 5–300Ameasured using two grazing incidence flat-field EUV spectrometers and in the VUV wavelength range of 300–2400Ameasured using three normal incidence 20 cm VUV spectrometers.BI–BV and NIII–NVII emission lines were identified in the discharges with the B and BN powder injection,respectively.Useful B and N emission lines which have large intensities and are isolated from other lines were successfully identified as follows:BI(1825.89,1826.40)A(blended),BII 1362.46A,BIII(677.00,677.14,677.16)A(blended),BIV 60.31A,BV 48.59A,NIII(989.79,991.51,991.58)A(blended),NIV765.15A,NV(209.27,209.31)A(blended),NVI 1896.80A,and NVII 24.78A.Applications of the line identifications to the advanced spectroscopic diagnostics were demonstrated,such as the vertical profile measurements for the BV and NVII lines using a space-resolved EUV spectrometer and the ion temperature measurement for the BII line using a normal incidence 3 m VUV spectrometer.
文摘介绍了东方超环(experimental advanced supereonducting tokamak, EAST)托卡马克上的两套快速极紫外(EUV)光谱仪系统波长的原位标定方法、结果及其应用。这两套谱仪均为掠入射平场谱仪,时间分辨均为5 ms·frame -1 。两套谱仪分别工作在20~500和10~130 的波段范围,由步进电机控制探测器在焦平面上移动实现整个观测波段上的波长扫描。利用这两套谱仪系统观测极紫外波段光谱,计算EAST中低-高Z杂质离子特征线辐射强度随时间的演化,监测和研究等离子体中杂质的行为。高Z杂质尤其是钨、钼等金属元素,发出的EUV波段光谱的构成非常复杂,准确识谱对谱仪精确的波长测量能力以及谱分辨能力要求很高,因此精确的波长标定是识别钨、钼等高Z杂质谱线以及研究它们行为的最关键的技术之一。利用EAST等离子体中类氢到类铍的低、中Z杂质的特征谱线以及它们的二阶甚至三阶谱线,结合谱仪系统的色散能力,对这两套快速极紫外光谱仪的波长进行了精确的原位标定。用于波长标定的杂质谱线有O Ⅷ 18.97 , O Ⅶ 21.60 , C Ⅵ 33.73 , Li Ⅲ 113.9 , Li Ⅲ 135.0 , Li Ⅱ 199.28 , Ar ⅩⅤ 221.15 , He Ⅱ 256.317 , He Ⅱ 303.78 , Ar ⅩⅥ 353.853 及C Ⅳ 384.174 等。利用波长标定的结果对观测到的EUV光谱进行谱线识别,两套谱仪观测到的绝大多数谱线波长与美国技术标准局(National Institute of Standards and Technology, NIST)数据库的标准波长相差分别小于0.08和0.03 。开发了谱仪波长原位标定程序模块,将这个模块内嵌到谱仪数据实时上传的交互式软件中,实现了全谱数据以及特征谱线强度随时间演化数据的实时处理和上传。同时利用开发的全谱分析交互式软件以及EAST上的数据查看软件,最终实现了快速EUV谱仪自采数据的准实时分析、读取和查看。
