REXEBIS In the Electron Beam Ion Source (EBIS) the 1+ ions are charge bred. The positive ions are trapped in an electron beam which knocks out electrons from the ions. EBIS working principle The positive ions are injected from the right and confined - radially in the potential well from a dense electron beam which is focused by a strong solenoidal magnetic field - longitudinally by two electrical potential barriers Inside the beam the ions perform axial, magnetron and cyclotron motions in an entangled way, as well as collide with other ions. EBIS cross-view Charge development During the confinement period (s to seconds), the ions are continuously bombarded with fast moving electrons from the electron beam. These knock out the electrons from the ions. When the desired charge state is reached, the ions are extracted to the right by applying an extraction voltage. Obtained charge state: Axial potential Radial potential

REXEBIS The REXEBIS is based on a 2 T superconducting solenoid. An immersed gun produces the electron beam and the electrons are absorbed in an iron-shielded collector. After a confinement < 20 ms a q/A > 1/4 is reached. filling tower racks collector position electron gun position insulator injection/extraction optics magnet iron shield turbo pumps 60/20 kV platform The REXEBIS platform is switched between 60 kV (at injection) and ~20 kV (at extraction) to convert the ISOLDE energy (60 keV) to ~20 keV·q in accordance with accelerator specifications. REX-EBIS data B = 2 T Eelectron = 5 keV confinement < 20 ms Ie = 0.5 A je = 250 A/cm2 Ltrap < 0.8 m Warm bore q/A ~ 1/4 Uplatform (kV) t 60 10-20 ms 100s 100 s 40 20 T=10 – 20 ms breeding injection extraction 5 V