During the summer and fall 2018, the Cornell High Energy Synchrotron Source (CHESS), underwent an upgrade that recast the facility as primarily a low emittance X-ray source. The upgrade replaced one sixth of the Cornell Electron Storage Ring (CESR) with six double-bend achromats, featuring four novel CHESS Compact Undulator (CCU) insertion devices, and switched CESR to single particle beam operation. At the time of this writing, the upgraded storage ring has achieved the CHESS-U design goal of operating with 200 mA of positron current at 6.0 GeV beam energy. Seven out of eleven CHESS-U beamlines are currently in X-ray user operation. The construction and the commissioning of the new section of the CESR accelerator required novel solutions to design, fabrication, and vacuum system operations. Significant design considerations and efforts were made to minimize X-ray ‘dark-time’, returning to operation less than 1 year. This paper describes the important milestones of the process, the solutions implemented, and the present status of CHESS-U.

在2018年夏季和秋季，康奈尔高能同步加速器源（CHESS）进行了升级，将设施重新铸造为主要是低辐射X射线源。此次升级用六个双弯消色差透镜取代了康奈尔电子存储环（CESR）的六分之一，具有四个新颖的​​CHESS紧凑型波荡器（CCU）插入设备，并且将CESR切换为单粒子束操作。在撰写本文时，升级的存储环已达到CHESS-U设计目标，即以6.0 GeV的束能量在200 mA的正电子电流下工作。X射线用户操作中目前有11条CHESS-U光束线中的7条。CESR加速器新部分的建造和试运行需要新颖的设计，制造和真空系统操作解决方案。为了将X射线的“暗时间”最小化，已进行了大量的设计考虑和工作，并在不到一年的时间内恢复了运行。本文介绍了该过程的重要里程碑，已实施的解决方案以及CHESS-U的现状。