NPS, Monterey, California
Niowave, Inc., Lansing, Michigan
MIT, Middleton, Massachusetts
Stanford University, Stanford, Califormia
Funding: This research is supported by the Office of Naval Research and the Joint Technology Office.
The Naval Postgraduate School (NPS) has begun the design and assembly of the NPS Free-Electron Laser (NPS-FEL). As part of this effort, the original dc gun-based injector system is being refurbished and upgraded. As described in the accompanying paper 'Status of the NPS-FEL' (these Proceedings), the overall NPS-FEL design parameters are for 40 MeV beam energy, 1 nC bunch charge, and 1 mA average beam current, in an energy-recovery linac configuration. As we move towards this configuration, the injector system will be incrementally upgraded to add photocathode capability, have a higher final beam energy, and improve the beam brightness, to meet the demands of the overall experimental program. This paper describes the current status of the injector system, the initial set of experiments planned, and the projected upgrade path.
NPS, Monterey, California
Stanford University, Stanford, Califormia
Funding: This research is supported by the Office of Naval Research and the Joint Technology Office.
The Naval Postgraduate School (NPS) has begun the design and assembly of the NPS Free-Electron Laser (NPS-FEL). The basic NPS-FEL design parameters are for 40 MeV beam energy, 1 nC bunch charge, and 1 mA average beam current, in an energy-recovery linac configuration. The NPS-FEL will make use of portions of the Stanford Superconducting Accelerator (decommissioned in 2007), in particular the injector system, Stanford/Rossendorf-style cryomodules and rf system. The injector will be gradually upgraded to improve beam properties and increase the injection voltage. Each cryomodule contains two, 9-cell TESLA-type 1.3 GHz cavities, each cavity powered by an individual 10 kW cw klystron. NPS has committed to refurbishing a building for the FEL, with approximate interior vault dimensions of 7 m x 20 m x 2.5 m. The building has overall dimensions of 12 m x 49 m and will house the vault, control room, and support equipment. This paper describes the overall goals of the program, initial experimental plans, and progress to date.
LANL, Los Alamos, New Mexico
NRL, Washington, DC
LLNL, Livermore, California
Stanford University, Stanford, Califormia
Beam-Wave Research, Inc., Union City
Funding: Supported by the High-Energy Laser Joint Technology Office
We are investigating spoke resonators that originally were proposed for moderate energy proton acceleration for application in high-average-current free-electron lasers (FEL). This structure holds the promise of alleviating the BBU limitations of conventional rf structures. Spoke resonator have several advantages: 1) strong coupling simplifies the access to higher order modes (HOM), 2) at the same frequency a spoke resonator is about half the size of an elliptical resonator, 3) the spokes provide additional mechanical stability and stiffening , 4) the power and HOM couplers can be attached to the cavity body and do not take up additional space along the length of the accelerator, 5) the presence of the spokes limits the polarizations of the HOMs to two orientations which facilitates the selection of HOM coupler positions. The rf performance of a spoke resonator specifically designed for high-current electron applications (beta=1.0) will be presented and compared with the expected performance of elliptical resonators designed for such applications. Besides the structure's effectiveness for acceleration also HOM properties will be presented.
