A PATH TOWARDS A COMPACT, CW FEL USING SUPERCONDUCTING RF ACCELERATORTECHNOLOGY

Recently, several compact FELs have been built based on pulsed linacs and RF photocathode guns, There is now an exciting opportunity to exte nd the capability of the technique to CW operation by incorporating th e recent development in superconducting electron accelerators. The hig her average power possible with CW operation will enhance the utility and the versatility of the compact FELs for fundamental research as we ll as for industrial application. Our vision of an eventual compact hi gh power FEL is one that is targeted to have a foot print of 1x6 m(2). It would consist of a CW RF superconducting photocathode gun closely coupled to a superconducting accelerator cavity, all in a single cryos tat, producing a 6-15 MeV beam. The helium refrigerator will be built into the compact dewar as is currently being done for the JAERI FEL in Japan. The FEL output will consist of 10-100 mu J pulses at 10-70 MHz repetition rate with average power greater than 1 kW. The FEL perform ance will be optimized in the wavelength range between 10 and 50 mu m, which is a difficult region for conventional laser techniques. Longer wavelengths can be generated via Cherenkov FEL, and X-rays can be pro duced via Thomson scattering.