上海光源真空紫外角分辨光电子能谱束线设计(英文)  

Design of VUV beamline for ARPES studies at SSRF

作　　者：马德伟[1] 乔山[1] 张新夷[1] 封东来[1] 

机构地区：[1]复旦大学物理系应用表面物理国家重点实验室,上海200433

出　　处：《光学精密工程》2007年第12期1844-1849,共6页Optics and Precision Engineering

基　　金：Supported by the Chinese Post-doctoral Science Foundation and the National Natural Science Foun-dation of China

摘　　要：在上海光源上设计了一条光子能量覆盖5 ～140 eV的高通量、高分辨的真空紫外角分辨光电子能谱束线。本光束线采用准周期椭圆偏振波荡器光源,其周期长度为0 .32 m,周期数为14。单色仪采用Dragon型,分为覆盖5 ～32 eV的低能分支和25 ～140 eV的高能分支。计算表明,当入射/出射狭缝开启宽度为5/5μm时,在整个能量扫描范围内,单色仪分辨率可以高达15 000 ～100 000 ,光学元件的面型误差对分辨率的影响最大。通量计算显示,样品处s偏振光子通量高达～1012phs/s。Shadow追迹模拟结果表明,设计的光束线具有很好的聚焦特性。Vacuum ultraviolet （VUV） beamlines have been playing an important role in studying the electronic structure of solids. Until now, over 30 VUV beamlines for Angle-resolved Photoemission Spectroscopy （ARPES） studies have been built in the synchrotron radiation facilities of US, Japan and Europe. In this work, we present a design of a high-resolution and high-flux VUV beamline covering 5-140 eV photon energy range at Shanghai Synchrotron Radiation Facility（SSRF） for ARPES studies. A quasi-periodic Elliptical Polarized Undulator （EPU） with 14 periods and each 0.32 m long is used as the source. A Dragon-type monochromator with two branches, a lower energy branch covering 5-32 eV and a higher one covering 25-140 eV, is employed. Calculations show that the total resolutions of the monochromator can reach up to 15 000-100 000 with entrance/exit slit openings of 5/5 /μm and the ultimate flux of the s-polarized photon on a sample exceeds -10^12 phs/s. The figure slope errors dominate the total resolution limit of the monochromator. Ray-tracing simulations show that the designed beamline has a good focusing performance. This beamline will be the first VUV beamline constructed at SSRF and will provide valuable experience for future constructions.

关 键 词：光束线设计 真空紫外 高分辨 高通量 

分 类 号：O657.62[理学—分析化学] TH838.3[理学—化学]