LATEST DEVELOPMENTS AT THE S-DALINAC

The recirculating superconducting linear accelerator S-DALINAC provides a continuous wave (cw) electron beam of up to 130 MeV for a wide range of nuclear and radiation physics experiments and serves as a driver for a Free-Electron-Laser. Here are the following topics are cosidered: (i) In order to improve the energy spread from presently 50 keV FWHM by a factor of 3-5 a new control system is under development. The concept considered first was a fully digital control system following the concept for the TTFL as a prototype for TESLA, but was later changed into a hybrid system consisting of a fast analog feedback circuit and a DSP-based unit. (ii) For online survey of the radiation background inside the accelerator hall an array of Compton diodes has been installed. The Compton diode was chosen as a detector since it was possible to develop a very compact, rugged, mechanically simple, inexpensive unit with integrated signal processing. (iii) A fast computer code (V-Code) using the model of ensembles to describe the beam properties was implemented to study injector beam dynamics. This is a first step in the development of an online tracking simulation. (iv) Results of measurements performed at the superconducting cavities which revealed the emission of light in conjunction with field emission are presented and discussed.