• A. Arnold
  FZD, Dresden

To fulfil the demand of future high power and high luminosity FEL and Storage Ring sources, an intensive electron beam with short bunch length, small emittance and large bunch charge is required. Laser driven superconducting radio frequency (SRF) photocathode guns in combination with SRF LINACs appear to be the best solution. First long term operation was demonstrated at the FZD*. In difference to the normal conducting guns, the application of static magnetic fields is not possible. Instead, the use of a transverse electric (TE) mode in parallel to the accelerating mode was proposed. Numerical simulations have shown that such RF focusing can be applied to compensate emittance growth**. This contribution will introduce a possibility to use the existing coaxial RF coupler of TESLA like cavities, as RF power input for TE modes in parallel. An additional coupler component outside the module satisfies the job of combining two frequencies from different sources to one load. Thus, it corresponds to the working principle of a high power RF diplexer. Based on the 3 1/2 cell FZD SRF gun, a concrete technical implementation and results of its operation at the cold cavity will be presented.

* J. Teichert et al., AIP Conf. Proc. 1149, 1119 - 1124 (2009).
** K. Flöttmann, D. Janssen, V. Volkov, Phys. Rev. ST Accel. Beams 7, 090702 (2004).