The NBS/NRL (National Bureau of Standards/Naval Research Laboratory) Free Electron Laser Facility,

Abstract : A free electron laser is being built whose electron beam source is the 185-MeV CW racetrack microtron (RTM) presently nearing completion. This accelerator is characterized by extremely good emittance epsilon sub n somewhat 10 micrometers and small energy spread delta gamma/gamma somewhat .0003 at full energy. A new photocathode injector operating on the 32nd subharmonic of the 2380-MHz RF frequency is being developed to increase the peak current to somewhat 2 A in 3-ps micropulses. Our wiggler design has 130 periods of lambda sub w = 28 mm with RMS wiggler parameter K somewhat 1. Three-dimensional calculations indicated that power gains of 10-30% per pass can be achieved for optical wavelengths in the range 200 nm to 10.0 micrometers. The design of the RTM and FEL will be described. This FEL is intended for use in a broad program of research applications in biomedicine and materials science.