工作波长大于100nm的高通量多用途光束线的设计

A large aperture versatile beamline working at wave length > 100nm

介绍国家同步辐射实验室光源二期工程圆二色与光声光谱光束线。该光束线采用一种改进的正入射型单色器，包括一块柱面前置镜、柱面光栅，无入射狭缝。前置镜接收 ４０ｍｒａｄ × ８ｍｒａｄ的同步辐射光，并将它在水平方向聚焦于样品处。柱面光栅（两块，覆盖１００－３００ｎｍ）完成同步光的单色化并将它在垂直方向聚焦于出射狭缝，出缝固定。该设计具有高通量（其光子通量为１０１２－１０１３ｐｈｏｔｏｎ／ｓ）、中等分辨率（０．３－５ｎｍ）、保持线偏振等优点。使用带 ＬｉＦ或 ＣａＦ２窗的超高真空阀门将光束线和实验站分隔，光束线工作在超高真空状态。

The design of a new beamline was introduced, which will be used for Circular - Dichroism and Photoacoustic spectroscopy at National Synchrotron Radiation Laboratory. An improved normal incident monochromator was adopted in the design. The beamline includes a prefocusing cylindrical mirror and a cylindrical guting, but no entrance slit. The mirror will accept a very large proportion of the dipole radiation (8 mrad of vertical beam, .and 40 mrad of horizontally), and focus the source sagittally on exit slit. The cylindrical grating will focus meridionally the source on the sample position, besides dispersion. The characteristics of such design are high flux (1012-1013 photons/s), moderate resolution (0. 3-5nm), reserving the linear polarization. A valve with LiF (or GaF2 ) window will be used to separate the beamline and experimental station. The beamline will be in ultra - high vacuum, but the experimental station will be N2 (or He) purged.