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The new 1.4 MeV/u front end HSI (HochStromInjektor) of the Unilac accelerates ions with A/q ratios of up to 65 and with beam intensities in emA of up to 0.25 A/q. The maximum beam pulse power is up to 1300 kW. During the stepwise linac commissioning from April to Septem-ber 1999 the beam behind of each cavity was analysed within two weeks. A very stable Ar1+ beam out of a vol-ume plasma source MUCIS was used mainly. The meas-ured norm. 80 % emittance areas around 0.45 pi mm mrad are close to the results from beam simulations. Up to 80 % of the design intensity at the linac exit were achieved. In February 2000 an U4+ beam from the MEVVA source was accelerated for the first time., Linac 2000, MOD11, 3 pages, 4 figures

With the new GSI High Current Injector, the beam pulse intensity will be increased by more than two orders of magnitude. The high beam power and the short stopping range at particle energies below 12 MeV/u can destroy accelerator components even during a single beam pulse. Therefore, the operation of the whole accelerator facility has required major changes in hardware, software and operating strategy. A sophisticated beam diagnostic system is indispensable for a safe operation. Preferably non-destructive devices were installed. Destructive elements, e.g. beam stoppers, slits, apertures, were improved in order to withstand the high beam power. Automatic damage prevention was realised by beam loss monitors comparing and evaluating very fast beam current transformer signals. Additionally, the component status will be controlled permanently. For foil stripping at 11.4 MeV/u, a magnetic beam sweeping system was installed Thereby, the hit area will be increased during one 100 micro sec pulse. During operation, manual variation of parameters has to be reduced. Set-up and automatic beam adjustment procedures have to exclude uncontrolled beam loss. The versatility of the UNILAC is enhanced by the possible three-beam operation on a pulse-to-pulse basis. Since November 1999 the upgraded UNILAC is serving the experiments., Linac 2000, MOD12, 3 pages, 5 figures