圓二色光譜是一個快速且簡易研究具有圓二色性物質之結構變化的重要技術，常應用於鑑定蛋白質的結構與變化、判別藥物的鍵結性、探討醣類反應性和生物薄膜功能等生物化學和結構生物的研究。同步輻射圓二色光譜利用同步輻射在真空紫外光區的良好線偏振性、高光通量和連續調變波長的特性，具有樣品需求量低，且可提供短波長光區的重要資訊等優點，可開拓新的應用領域，特別是在結構和功能基因體的研究。國家同步輻射研究中心於 2008年8月在SEYA光束線完成圓二色光譜實驗站的建造，並開放用戶使用，特撰文介紹實驗站與應用。

Circular dichroism spectroscopy is a simple and quick method for studying structural alterations of optical materials in aqueous solution under various experimental conditions, for example, as a function of temperature or chemical denaturant. Applications in biochemistry and structural biology include characterization of proteins and their conformation changes and dynamics, as well as examining macromolecular interactions and functions of biological membranes. Synchrotron radiation circular dichroism (SRCD) spectroscopy requires small amount of samples and can provide new information in shorter wavelength region by taking advantages of synchrotron radiation-highly linear polarization, high photon flux and continuous tenability in vacuum ultraviolet region; accordingly, this spectroscopic method can further explore new research areas, particularly in structural and functional genomics. In this article, we will introduce the new SRCD end station at SEYA beamline in NSRRC and its applications.