Status report on the Duke FEL facility

At the Duke Free Electron Laser (FEL) Laboratory, there are two FEL machines: the Mark III infrared FEL and the OK-4/Storage Ring, which produces an UV and XUV laser beam as well as gamma rays via Compton backscattering. The recent status of Mark-III machine is described in another paper. Here we will concentrate on the new development of the OK-4/Storage Ring FEL and its performance and capabilities. A brief history of this machine and the future plan are also given in this paper.