MILESTONE EXPERIMENTS FOR SINGLE-PASS UV X-RAY FELS/

In the past decade, significant advances have been made in the theory and technology of high brightness electron beams and single pass FELs. These developments facilitate the construction of practical UV and X- ray FELs and has prompted proposals to the DOE for the construction of such facilities. There are several important experiments to be perfor med before committing to the construction of dedicated user facilities . Two experiments are under construction in the IR, the UCLA self-ampl ified spontaneous emission experiment and the BM, laser seeded harmoni c generation experiment. A multi-institution collaboration is being or ganized about a 210 MeV electron linac available at BNL and the 10 m l ong NISUS wiggler. This experiment will be done in the UV and will tes t various experimental aspects of electron beam dynamics, FEL exponent ial regime with gain guiding, start-up from noise, seeding and harmoni c generation. These experiments will advance the state of FEL research and lead towards future dedicated users' facilities.