• H. Vormann, W.A. Barth, L.A. Dahl, W. Vinzenz, S.G. Yaramyshev
  GSI, Darmstadt
• A. Kolomiets, S. Minaev
  ITEP, Moscow
• U. Ratzinger, R. Tiede
  IAP, Frankfurt am Main

To provide for the high beam currents as required of the FAIR project, the GSI Unilac High Current Injector (HSI) must deliver 18 mA of U⁴⁺ ions at the end of the prestripper section. With the design existing up to 2008, the RFQ could not reach the necessary beam currents at the RFQ output, as simulations had shown. Furthermore, parts of the existing LEBT must be modified, and a new straight source branch must be added to provide for the full required beam current. As a first step of an HSI frontend upgrade, the RFQ has been modernized in summer 2009 with a completely new electrode design. Commissioning of the HSI has shown that the transmission of the RFQ increased significantly (from 55% to 85% in high current Uranium operation, 95% in medium current operation). As expected, further bottlenecks for the transmission of the complete HSI (matching LEBT-to-RFQ, matching to the Superlens) have been detected. An upgrade of LEBT magnets is foreseen for 2010, the additional linear source branch will follow.

• H. Podlech, M. Amberg, M. Busch, F.D. Dziuba, U. Ratzinger, R. Tiede
  IAP, Frankfurt am Main
• W.A. Barth, S. Mickat
  GSI, Darmstadt

The search for Super-Heavy Elements (SHE) is one of the frontiers in nuclear physics. By trend the production cross sections decrease significantly for larger proton numbers and heavier nuclei, respectively. To limit the required beam time it is necessary to use the highest available intensity. This prefers cw operation and the use of superconducting cavities. A cw operated superconducting linac using CH-cavities at GSI has been designed. As front end the existing 10⁸ MHz High Charge Injector (HLI) will be used which is presently being upgraded for cw operation. The superconducting part of the linac covers the energy between 1.4 AMeV and 7.5 AMeV. It consists of 9 multi-cell CH-cavities operated at 217 MHz. Each cavity is optimized for a specific particle velocity but without beta profile. Above 3.5 AMeV the linac is fully energy variable. The first superconducting CH-cavity is already under construction and will be tested with beam delivered by the HLI. The talk covers the development of the prototypes and the overall design including beam dynamics issues.

• D. Raparia, J.G. Alessi, E.N. Beebe, K. Kondo, R.F. Lambiase, V. LoDestro, R. Lockey, M. Mapes, A. McNerney, M. Okamura, D. Phillips, A.I. Pikin, J. Ritter, J. Scaduto, L. Smart, L. Snydstrup, M. Wilinski, A. Zaltsman
  BNL, Upton, Long Island, New York
• R. M. Brodhage, U. Ratzinger, R. Tiede
  IAP, Frankfurt am Main
• T. Kanesue
  Kyushu University, Hakozaki

The EBIS based preinjector for RHIC is now being commissioned. The Linac was delivered in April 2010 and commissioning started in May, 2010. It accelerates ions from 0.3 MeV/u to 2 MeV/u with 27 accelerating gaps, one internal quadrupole triplet, and operates at 100.625 MHz. The Linac is followed by a beam transport line to Booster which includes seven quadrupoles, two bunchers, and an achromatic bend system with resolution of 500 at 2 MeV/u to select the required charge state. Diagnostics include a pepperpot emittance probe, phase probes , fast Faraday cup, adjustable slits, three sets of multiwire profile monitors, three current transformers, two Faraday cups, and two beam stops. This contribution will report results of linac tuning and cold measurements, and commissioning of the Linac and high energy transport line with helium and gold beams.