摘要
利用椭圆从一个焦点发射出的光线经椭圆面反射必汇聚于另一焦点的性质,设计了基于620～6200eV的X射线椭圆弯晶谱仪。文中分析了系统原理,完成了谱仪光学色散系统、探测系统及仪器的研制。采用KAP、LiF、PET、MiCa作为色散元件,其2d值在0.4～2.6nm、Bragg角为30°～67.5°,晶体尺寸为120×8×0.2mm,偏心率为0.9586,焦距1350mm,光程长1456mm,分析器基底材料用数控铣床加工。实验在上海"神光Ⅱ"号装置上实施,激光能量为150J,波长为0.35mm,真空度为3×10-3Pa。为达到光学对准,采用了小点光源以及精密望远镜对中。实验结果显示出金靶在0.63～0.79nm范围,其分辨力(△λ/λ)达到了1/486。谱的分辨力还与晶体特征和激光靶源尺寸有关。谱仪性能良好、使用方便、简单,具有高的收集效率和分辨能力,能够有效获取激光惯性约束聚变中激光等离子体发射光谱的丰富信息。
Based on the theory that is ray emitted from a focus (front) of an ellipse will converge on the other focus (back) by the reflection on the elliptical surface, the Elliptical Crystal Spectrograph (ECS) in the X-ray region of 620～6 200 eV was designed. The principle of the system was analyzed,and the design and manufacture were accomplished. KAP,LiF,PET and MiCa are used as dispersive elements covering Bragg angle from 30° to 67.5°. The crystal sizes are 120×8×0.2 mm with the curved analyzer substrate of eccentricity ε=0.958 6, focal distance of 1 350 mm,and optical path length of 1 456 mm. The analyzer of the elliptical profiles was machined into a suitable substrate material using a Computer-Controlled milling machine. The Elliptical Crystal Spectrograph was experimented on Shanghai 'Shenzhou Ⅱ' with laser energy of 150 J,laser wavelength of 0.35 μm,and chamber vacuum level 3×13^(-3) Pa. To achieve optical alignment with a small point source,an aligned telescope was precisely fitted to the elliptical analyzer block. The result shows that spectra of Au target can be measured in 0.63～0.709 nm with a resolution of 1/486(△λ/λ). It is found that the resolution of the spectrograph depends on the rocking curve and the thickness of the crystal and the laser spot diameter. In addition,ECS is simpler and easier to use,with a higher collecting efficiency and a better resolution. It can effectively obtain abundant information of the laser-plasma emission spectra in an inertial confinement fusion.
出处
《光学精密工程》
EI
CAS
CSCD
2004年第4期415-419,共5页
Optics and Precision Engineering
基金
国家863 804课题资助项目(No.803 804 3)
关键词
晶体谱仪
激光等离子体
X射线谱
光谱分析
crystal spectrograph
laser plasma
X-ray spectrum
spectral analysis
