High-intensity low energy beam transport design studies for the new injector linac of the UNILAC

GSI will replace the Wideroe prestripper linac by an RFQ and IH-type accelerator presently under construction. The new prestripper linac should deliver beam intensities to fill up the heavy ion synchrotron SIS to the space charge limits for all ions. In case of uranium the new injector has to deliver 15 emA U4+. One of the two existing ion-source terminals has already been rebuilt for installation of the high current sources of CHORDIS- and MEVVA-type. Therefore, investigations of high-current beam transport have been made in the existing LEBT. For that, additional beam diagnostic elements have been installed: beam transformers, emittance measurement devices, residual gas ion spectrometer. The measured beam properties, e.g. transverse emittance, degree of space charge compensation, support the design of the future LEBT. According to the various requirements two layouts of the new LEBT have been studied so far. (author)