A Microwave Beam Waveguide Undulator for a Brilliant above 100 Kev Photon Source*

For generation of photons above 100 keV with a magnetic field strength in the range 0.2-0.5 Tesla, an undulator wavelength λu shorter than 5 mm may be needed with beam in the Advanced Photon Source (APS) storage ring. A microwave beam waveguide undulator system has been investigated for generation of such light. The waveguide structure consists of two parallel reflector surfaces that can be derived from an elliptically cylindrical waveguide. The structure can support deflecting TEm0 modes with very low microwave loss. A microwave ring resonator circuit employing the beam waveguide is considered to construct an undulator with the above requirement. Microwave properties of the beam waveguide structure have been investigated, and the design criteria for a microwave undulator are discussed.