Wang G M, Shaftan T, Cheng W X, Guo W, Ilinsky P, Li Y, Podobedov B, Willeke F
National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11793, USA.
Rev Sci Instrum. 2016 Mar;87(3):033301. doi: 10.1063/1.4942903.
National Synchrotron Light Source II (NSLS-II) is a new third-generation storage ring light source at Brookhaven National Laboratory. The storage ring design calls for small horizontal emittance (<1 nm-rad) and diffraction-limited vertical emittance at 12 keV (8 pm-rad). Achieving low value of the beam size will enable novel user experiments with nm-range spatial and meV-energy resolution. The high-brightness NSLS-II lattice has been realized by implementing 30-cell double bend achromatic cells producing the horizontal emittance of 2 nm rad and then halving it further by using several Damping Wigglers (DWs). This paper is focused on characterization of the DW effects in the storage ring performance, namely, on reduction of the beam emittance, and corresponding changes in the energy spread and beam lifetime. The relevant beam parameters have been measured by the X-ray pinhole camera, beam position monitors, beam filling pattern monitor, and current transformers. In this paper, we compare the measured results of the beam performance with analytic estimates for the complement of the 3 DWs installed at the NSLS-II.
国家同步辐射光源II（NSLS-II）是布鲁克海文国家实验室的一个新的第三代储存环光源。储存环的设计要求水平发射度小（<1纳米弧度），在12千电子伏特时垂直发射度达到衍射极限（8皮米弧度）。实现低束斑尺寸将使能进行具有纳米级空间分辨率和毫电子伏特能量分辨率的新型用户实验。通过采用30单元双弯消色差单元实现了高亮度的NSLS-II晶格，该单元产生的水平发射度为2纳米弧度，然后通过使用几个阻尼波荡器（DW）将其进一步减半。本文重点研究了DW对储存环性能的影响，即对束发射度的降低以及能量分散和束寿命的相应变化。相关束参数已通过X射线针孔相机、束位置监测器、束填充模式监测器和电流互感器进行了测量。在本文中，我们将束性能的测量结果与安装在NSLS-II的3个DW的补充分析估计值进行了比较。
