NSRL真空紫外圆二色光谱实验站设计及性能测试

The design and commissioning of the vacuum-ultraviolet circular dichroism facility at NSRL

本文介绍了中国科学技术大学国家同步辐射实验室(NSRL)真空紫外圆二色光谱测量装置的设计及安装调试结果,包括光学设计、样品池、数据采集系统、以及标准样品测量的结果。该实验站连接在弯铁光源和正入射单色器光束线的末端,在0.5nm光谱分辨下样品点的光子通量大于1012s-1。采用线性起偏器获得线偏振同步辐射,经过光弹调制器(PEM)获得重复频率约50kHz、左右旋交替的圆偏振光。通过高压伺服使得光电倍增管平均输出电流不变;使用锁相放大器采集与PEM同频的交流信号,得到圆二色光谱信号。常规实验条件(氮气氛保护、水作为溶剂、标准样品池)下,可测试的光谱范围是178—300nm。通过采用特殊溶剂、超短光程氟化物样品池等手段,可以将测试的短波限推至140nm。

This paper describes the design and commissioning of the vacuum-ultraviolet circular dichroism facility at NSRL. At 0.5nm resolution, the normal incident beamline can provide ultraviolet and vacuum-ultraviolet radiation at fluxes higher than 1012ph/s, which is converted into the plane polarized light using a polarizer and subsequently converted into the circularly polarized light using a photoelastic modulator with a switching frequency of 50 kHz. Example spectra of (1s)-(+)-10-camphorsulphonic acid (CSA) a...