  The Jefferson Lab (JLab) IR Demo Free Electron Laser (FEL) has completed
commissioning and is initiating user service. The FEL - a high repetition rate,
low extraction efficiency wiggler-driven optical cavity resonator - produces
over 1 kW of tuneable light on intervals in a 3-6 micron wavelength range. It
is driven by a 35-48 MeV, 5 mA superconducting RF (SRF) based energy-recovering
continuous wave (CW) electron linac. The driver accelerator meets requirements
imposed by low energy, high current, and a demand for stringent beam control at
the wiggler and during energy recovery. These constraints are driven by the
need for six-dimensional phase space management, the existence of deleterious
collective phenomena (space charge, wakefields, beam break-up, and coherent
synchrotron radiation), and interactions between the FEL and the accelerator
RF. We will detail the system design, relate commissioning highlights, and
discuss present performance.
