Operational status of the uranium beam upgrade of the ATLAS accelerator

The Positive-Ion Injector (PII) for ATLAS is complete. First beams from the new injector have been accelerated and used for experiments at ATLAS. The POI consists of an ECR ion source on a 350-kV platform and a low-velocity superconducting linac. The first acceleration of uranium for the experimental program has demonstrated that the design goals of the project have been met, Since the summer of 1992, the new injector has been used for the research program approximately 50% of the time. Longitudinal beam quality from the new injector has been measured to be significantly better than comparable beams from the tandem injector. Changes to the mix of resonators in the main ATLAS accelerator to match better the velocity profile for heavy beams such as uranium are nearly complete and uranium energies up to 6.45 MeV per nucleon have been achieved. The operating experience of the new ATLAS facility will be discussed with emphasis on the measured beam quality as well as achieved beam energies and currents