Cooling of highly charged ions—the HITRAP facility and Cooler trap

Abstract

HITRAP is a facility at GSI in Darmstadt for decelerating, cooling and storing heavy, highly charged ions. It is designed to decelerate a beam of A/q < 3 particles with an energy of 4 MeV per nucleon as provided by the heavy ion storage ring ESR. HITRAP's decelerating linear accelerator (linac) will decelerate ions down to 6 keV per nucleon and then inject them into a Penning trap for cooling. The trap will capture bunches of up to 105 ions as heavy as U92+ in flight, cool and store them. After extraction from the cooler trap, the vertical beam line (VBL) transports the cold ions to the experiments. The linac has shown to decelerate ions down to 500 keV per nucleon on-line and to 6 keV per nucleon off-line. Recent tests with electrons and ions injected into the trap showed the necessity of a more careful electric and magnetic field alignment. An installed test ion source as well as a system of apertures and position sensitive diagnostics will be used to align the fields. A highly charged ion beam from a small room temperature electron beam ion trap was used for commissioning the VBL.