TU Darmstadt, Darmstadt, Germany
Since 1991 the superconducting Darmstadt linear accelerator S-DALINAC provides an electron beam of up to 130 MeV for nuclear and astrophysical experiments. The accelerator consists of an injector and four main linac cryostats, where the superconducting 3 GHz cavities are operated in a liquid helium bath at 2 K. For the injector upgrade program, the RF power delivered to the beam had to be increased from 500 W to 2 kW. Therefore, the coaxial power couplers have to be replaced by new waveguide couplers introducing only small transversal kicks to the beam. Consequently, modifications to the cryostat-module and had become necessary. We review on the design of the module and some interesting features and give details on the tuning of the newly built 20-cell cavities. The paper will close with an outlook towards the installation of an additional recirculation path planed in 2013.
