Experiments with Heavy Ions in Traps

The GSI midterm project HITRAP is a planned ion trap facility for capturing and cooling of highly charged ions (HCI) produced at GSI in the heavy-ion complex of the UNILAC-SIS accelerators and the ESR storage ring. In this facility heavy highly-charged ions up to uranium will be available as bare nuclei, hydrogen-like ions or fewelectron systems at low temperatures. The trap for receiving and studying these ions is designed for operation at extremely high vacuum by cooling to cryogenic temperatures. The stored highly charged ions can be investigated in the trap itself or can be extracted from the trap at energies up to about 30 keV/q. The basic components constituting the HITRAP facility are outlined in Fig. 1. Highly charged ions are accelerated in the heavy-ion synchrotron SIS, stripped in a foil to the desired charge state and injected into the Experimental Storage Ring (ESR). For bare or hydrogen-like ions, energies of a few hundred MeV/u are required. In the ESR the ions will be decelerated to an energy of 3 MeV/u. It is planned to demonstrate this low-energy operation mode of the ESR during 2001. They will then be extracted in a fast-extraction mode as short ion bunches.