Beam-Preparation with REXTRAP for the REX-ISOLDE Experiment

REX-ISOLDE is a post-accelerator for radioactive ions located at the ISOLDE facility at CERN. Its task is to accelerate the radioactive ions coming from the on-line mass separator ISOLDE from 60 keV to a final energy of 2.2 MeV/u. To achieve this goal with a compact and cost-efficient setup a new concept was proposed. First the ions are accumulated in a Penning trap (REXTRAP), then the ions are transported to an EBIS (Electron Beam Ion Source), where their charge-state will be increased. Due to the high charge-state of the ions the following linear accelerator can be built comparatively compactly. In the framework of this thesis the construction and commissioning phase of REX-TRAP is described. REXTRAP is a large, gas-filled Penning trap whose aim is to store and cool the radioactive ions coming from ISOLDE. After listing the physics motivation for building REX-ISOLDE and describing its elements, the theory of a Penning trap as well as the setup of REXTRAP is explained. Fi-nally test results for REXTRAP are presented followed by a discussion on how REXTRAP in the present setup can fulfill the demands for the operation of REX-ISOLDE.