Publikationsrepositorium - Helmholtz-Zentrum Dresden-Rossendorf

A RF photo injector with a superconducting cavity (SRF gun) for installation at the Radiation Source ELBE was developed within a collaboration of BESSY, DESY, FZD, and MBI. This new and promising injector type allows CW operation and has the potential for the production of high-brightness electron beams. The gun cryostat, the electron diagnostic beamline, and the driver laser with optical beamline were installed. In November 2007 the first beam was produced. In 2008 beam parameter measurements with Cs2Te photo cathodes were carried out. Due to problems during the cleaning of the cavity, the design gradient could not be reached. Thus the SRF gun is operating now with a peak field of 17.5 MV/m which corresponds to electron energy of 3 MeV. In 2009 the cathode transfer system was upgraded, the bunch lengths measurement based on Cherenkov radiation was put into operation, and the connection beamline to ELBE was installed in the winter shutdown. In February, the first beam of the SRF gun was injected to ELBE and accelerated. Parallel to the commissioning and operation of the SRF gun, an improved design for the gun cavity was created and two now cavities, one made of RRR300 Nb and one made of high-grain Nb was fabricated in collaboration with JLab.