椭圆弯晶谱仪波长分辨能力的改进  

Improvement of spectral resolution power for an elliptically curved crystal spectrometer

作　　者：王瑞荣[1,2] 陈伟民[1] 王伟[2] 

机构地区：[1]重庆大学光电技术及系统教育部重点实验室,重庆400044 [2]上海激光等离子体研究所高功率激光物理国家实验室,上海201800

出　　处：《光学精密工程》2010年第6期1303-1308,共6页Optics and Precision Engineering

基　　金：国家863高技术研究发展计划资助项目

摘　　要：讨论了椭圆弯晶谱仪的波长分辨能力。在假设谱线的固有宽度可以忽略的情况下,对两种实际影响椭圆弯晶谱仪波长分辨能力的主要因素,即光源空间尺寸和非理想椭圆分光晶面进行了分析。分别对上述两种情况进行了数学建模和数值模拟仿真。定量地分析了非理想椭圆晶面和光源空间尺寸对椭圆弯晶X射线谱仪波长分辨本领的影响程度,并给出了出射狭缝宽度与椭圆弯晶谱仪波长判读加宽的关系。从理论上论证了光源空间尺寸在限制谱仪的波长分辨能力方面仍然起关键主导作用;结合椭圆分光晶体的结构参数,合理地选择出射狭缝宽度,可使谱仪达到足够好的光谱分辨率和信噪比。用搭建的实验平台进行了实验测试,结果表明,当出射狭缝宽度(2δ)为10mm时,实测的谱线半高全宽(Δλ)为3.1×10-3nm;2δ为4mm时,Δλ为2.3×10-4nm,实测结果佐证了仿真结果的正确性。The wavelength resolution power of a elliptically curved crystal spectrometer is discussed.After the spectral line profile caused by itself is supposed to be neglected,two main factors effecting on the wavelength resolution power of the spectrometer are analyzed.The first one is mainly that the source center is not on the focus of the ellipsoid and the source size can not be ignored.The other one is that the X-ray is reflected from irregular crystal surface,and it is not an ideal ellipsoid.In order to improve the wavelength measuring precision of the spectrometer,two simulating models are established according to the above mentioned factors.Then the two models are analyzed and the relation between the wavelength resolution power and the exit aperture slit width is presented by digital calculation.Meanwhile,a number of experimental investigations on the wavelength-resolved characteristics of the diagnostic system are conducted under a variety of slit width conditions.The wavelength resolution power affected by the un-ideal crystal surface and the source size is quantitatively analyzed with the spectrometer successfully.The experiments show that obtained results are in agreement with the calculation data.When the exit aperture slit width（2δ） is 10 mm,the full width at half maximum（λ） is 3.1×10-3 nm;the 2δ is 4 mm,and the λ is 2.3×10-4 nm.These results prove the validity of simulated results.

关 键 词：弯晶谱仪 分辨能力 狭缝宽度 

分 类 号：TH744.1[机械工程—光学工程]