The NIST/NRL free-electron laser facility

A free-electron laser (FEL) user facility is being constructed at the National Institute of Standards and Technology (NIST) in collaboration with the Naval Research Laboratory (NRL). The FEL, which will be operated as an oscillator, will be driven by the electron beam of the racetrack microtron (RTM) that is nearing completion. Variation of the electron kinetic energy from 17 MeV to 185 MeV will permit the FEL wavelength to be tuned from 200 nm to 10 μ. Performance will be enhanced by the high brightness, low energy spread, and continuous-pulse nature of the RTM electron beam. A new injector is being designed to increase the peak current of the RTM. A 3.6-m undulator is under construction, and the 9-m optical cavity is under design. The FEL will emit a continuous train of 3-ps pulses at 66 MHz with an average power of 100-200 W, depending on the wavelength, and a peak power of up to several hundred kilowatts. An experimental area is being prepared with up to five stations for research using the FEL beam. Initial operation is scheduled for 1991