Latest Developments from the S-dalinac

The S-DALINAC is a 130 MeV superconducting recirculating electron accelerator serving several nuclear and radiation physics experiments as well as driving an infrared free-electron laser. A system of normal conducting rf resonators for noninvasive beam position and current measurement was established. For the measurement of gammaradiation inside the accelerator cave a system of Comptondiodes has been developed and tested. Detailed investigations of the transverse phase space were carried out with a tomographical reconstruction method of optical transition radiation spots. The method can be applied also to nonGaussian phase space distributions. The results are in good accordance with simulations. To improve the quality factor of the superconducting 3 GHz cavities, an external 2K testcryostat was commissioned. The influence of electrochemical polishing and magnetic shielding is currently under investigation. A digital rf-feedback system for the accelerator cavities is being developed in order to improve the energy spread of the beam from the S-DALINAC.