越来越多的第三代光源进入运行。它们全部成功地达到预期的性能。其中有些,象法国的欧洲同步辐射装置(ESRF),达到的亮度比其初始目标提高了两个数量级。现有的机器运行经验表明存在某些缺点,在它们的设计中可以综合可能的修正,得到新方案。这些修正包括:以更高的亮度在衍射极限运行,更高的位置稳定性,用更大的动量可接收度与低色散性组合提高杜歇克(Touschek)寿命,以及反馈横向耦合群聚阻抗壁的不稳定性,有效地控制纵向耦合群聚的不稳定性,在单个群聚中获得更高电流,在环中选择位置以本地损失得到更好信噪比,并避免在束线方向发射高能轫致光子,永久注入的可能性,产生聚焦光子束,高质量插入装置等。在最近5年里,直线加速器驱动的自放大自发辐射自由电子激光器(SASEFEL),显示强劲的研究和发展态势。SASEFEL构成真正的第四代光源,结果鼓舞人心。但是,在按计划进行X射线自由电子激光装置之前,仍然还有一段路要走,因此,对用户来说,储存环在相当长一段时间里仍是极好的光源。 More and more third-generation light sources into operation. All of them successfully achieved the expected performance. Some, like the European Synchrotron Radiation Facility (ESRF) in France, achieved a brightness increase of two orders of magnitude more than its original goal. Existing machine operating experience shows that there are some shortcomings in their design which can be combined with possible modifications to get a new solution. These corrections include: operation at diffraction limits with higher brightness, higher positional stability, greater Touschek lifetime with a combination of greater momentum acceptability and low dispersion, and feedback of laterally-coupled bulk impedances Wall instabilities effectively control the instability of longitudinally coupled constellations, higher currents in a single constellation, better signal-to-noise ratio at selected locations in the ring for local losses, and avoidance of emission in the beamline direction High energy 轫 induced photons, the possibility of permanent injection, resulting in focused photon beam, high quality insertion devices. Linear accelerator-driven self-amplified spontaneous emission free-electron lasers (SASEFEL) have shown strong research and development momentum in the last five years. SASEFEL constitutes a true fourth-generation light source, the result inspiring. However, there is still some way to go before the planned X-ray free-electron laser device is planned so that the storage ring remains an excellent light source for users for a long time.