• S.V. Benson, K. Beard, C.P. Behre, G.H. Biallas, J. Boyce, D. Douglas, H.F.D. Dylla, R. Evans, A.G. Grippo, J.G. Gubeli, D. Hardy, C. Hernandez-Garcia, K. Jordan, L. Merminga, G. Neil, J.P. Preble, M.D. Shinn, T. Siggins, R.L. Walker, G.P. Williams, S. Zhang
  Jefferson Lab, Newport News, Virginia
• N. Nishimori
  JAEA/FEL, Ibaraki-ken

Funding: This work supported by the Office of Naval Research, the Joint Technology Office, the Commonwealth of Virginia, the Air Force Research Laboratory, the US Army Night Vision Laboratory, and by DOE Contract DE-AC05-84ER40150.

After demonstrating 10 kW operation with 1 second pulses, the Jefferson Lab program switched to demonstrating high power operation at short wavelengths using a new 8 cm period wiggler and a THz suppression chicane. We report here on the lasing results to date using this new configuration. We have demonstrated a large reduction in THz heating on the mirrors. We have also eliminated heating in the mirror steering assemblies, making operation at high power much more stable. Finally, we have greatly reduced astigmatism in the optical cavity, allowing operation with a very short Rayleigh range. The laser has been tuned from 0.9 to 3.1 microns using the new wiggler. User experiments commenced in April of 2005 with the FEL Upgrade operating over the 1-3 micron range. We are in the process of installing a 5.5 cm permanent magnet wiggler that will give us even larger tuning range and higher power.

Corresponding author: Tel: 1-757-269-5026; fax: 1-757-269-5519; E-mail address: felman@jlab.org

• R. Hajima, H. Iijima, N. Kikuzawa, E.J. Minehara, R. Nagai, N. Nishimori, T. Nishitani, M. Sawamura, T. Yamauchi
  JAEA/FEL, Ibaraki-ken

An energy-recovery linac for a high-power free-electron laser is in operation at Japan Atomic Energy Research Institute (JAERI). In this paper, we report results of research activities and future plans of JAERI ERL-FEL, which are the construction of FEL transport line, the operation of newly-installed RF controller and IOTs, the development of super-lattice photo cathode.

• E.J. Minehara, R. Hajima, H. Iijima, N. Kikuzawa, R. Nagai, N. Nishimori, T. Nishitani, M. Sawamura, T. Yamauchi
  JAEA/FEL, Ibaraki-ken

The JAERI high power ERL-FEL has been extended to the more powerful and efficient free-electron laser (FEL) than 10kW for nuclear energy industries, and other heavy industries like defense, shipbuilding, chemical industries, environmental sciences, space-debris, and power beaming and so on. In order to realize such a tunable, highly-efficient, high average power, high peak power and ultra-short pulse FEL, we need the efficient and powerful FEL driven by the JAERI compact, stand-alone and zero boil-off super-conducting RF linac with an energy-recovery geometry. Our discussions on the ERL-FEL will cover the current status of the 10kW upgrading and its applications of non-thermal peeling, cutting, and drilling to decommission the nuclear power plants, and to demonstrate successfully the proof of principle prevention of cold-worked stress-corrosion cracking failures in nuclear power reactors under routine operation using small cubic low-Carbon stainless steel samples.