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A: Fachverband Atomphysik

A 17: Atomic Systems in External Fields III

A 17.7: Vortrag

Mittwoch, 4. März 2009, 15:45–16:00, VMP 6 HS-C

The Cooler Trap of the HITRAP Facility at GSI — Frank Herfurth¹, Heinz-Jürgen Kluge¹, •Stephen Koszudowski¹, Giancarlo Maero¹, Oliver Kester¹, Wolfgang Quint¹, and Stefan Schwarz² — ¹GSI, 64291 Darmstadt — ²NSCL/MSU, East Lansing, USA

A dedicated Cooler Trap for the HITRAP facility at GSI has been designed and built. Here bunches of 10⁵ heavy, highly charged ions up to U⁹²⁺ can be trapped and cooled for precision experiments in atomic and nuclear physics. The trap is a cryogenic multi-ring cylindrical Penning trap, which enables a nested trap configuration.

Two cooling mechanism are employed: electron and resistive cooling. For the electron cooling 10¹⁰ electrons from a photoelectron source developed at MPIK Heidelberg will be fed into the trap. Recombination losses in the cooling process are small down to 10eV. To go to lower energies, resistive cooling via a resonant circuit at 4K is employed. Simulations of the resistive cooling have shown fast cooling (within 0.1s) of the center of mass motion down to a few eV. The following tail has a cooling constant of about 3.7s.

We detect the ions from the induced signal in the resonant circuit, which is fed out via a cryogenic amplifier. A second resonant circuit is installed to detect the cyclotron frequency of the ions. This can also be used for monitoring the axial frequency of the electrons. First tests of the trap will take place beginning of 2009. Therefore a H⁺ ion source and an EBIT for highly charged ions were bought and set up. The whole set up will be available for experiments later in 2009.