Lessons Learned for the Past 3-Years of Insertion Device Installation and Operation at the National Synchrotron Light Source-II

概要

The National Synchrotron Light Source-II (NSLS-II) is the latest storage ring of 3 GeV energy at the Brookhaven National Laboratory(BNL), U.S.A. The horizontal emittance of the electron beam with six 3.4m long damping wigglers (DWs) resident in the storage ring is 0.9 nm.rad. This could be further reduced with more insertion devices (IDs) added to the storage ring. The storage ring commissioning was completed by June 2014. At present it is operated with 275mA of ring current with top-up operation. As of March 2017, a total of eighteen ID and BM beamlines are now in operation. The various types of insertion devices are as follows: Hybrid permanent magnet DWs (100mm long period), Apple-II type elliptically polarizing undulators (EPUs) with various period lengths (49mm to 105mm), In-vacuum undulators (IVUs) of 20mm to 23mm period length and three pole wigglers (3PWs) with 1.13T peak field.
There were many positive and negative experiences had during the past three years of operation at the NSLS-II ring. Some examples of positive features are; pro-active over-all design to maximize the beam stability; in-house design of BPM electronics, active non-linear kick compensation for Apple-II EPUs; and side viewport windows for IVUs, etc. Some examples of negative ones are; a lack of cranes in the building; relatively high temperature (29.5Cº) cooling water; a very narrow tunnel cross section; and a lack of maintenance ability of control systems; and procurement difficulties, etc. Lessons learned for various systems and project management are described in this talk.