Berlin 2005 – wissenschaftliches Programm
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A: Atomphysik
A 17: Cold Atoms; Ultra-cold Atoms; and Atoms in Traps; BEC; II
A 17.4: Fachvortrag
Mittwoch, 9. März 2005, 14:45–15:00, HU 3075
Mixed-Species Ion Plasmas in a Linear RF-Trap — •Peter Blythe, Ulf Fröhlich, Bernhard Roth, Helmut Wenz, and Stephan Schiller — Heinrich-Heine-Universität Düsseldorf
Low-temperature sources of particles are of interest in
many areas of physics, e.g.
precision measurements to test QED effects and fundamental constants.
One promising avenue towards the generation of new ultracold atomic and
molecular
species not accessible to direct cooling is sympathetic cooling in ion
traps. For strong
cooling a phase transition from a fluid state to an ordered (crystalline)
state occurs and
the properties of such plasmas can be studied.
In a linear rf-trap, we have produced ultracold mixed-species ion plasmas
by
sympathetic cooling of
light atomic and molecular ions (molecular hydrogen and helium isotopes,
BeH+, BeD+)
using laser-cooled 9Be+. We have studied the properties of the
generated ion plasmas, both for
spheroidal and ellipsoidal symmetry, as well as observed chemical reactions
between the atomic coolants and neutral light molecules with high
spatial resolution down to the single particle level. The experimental
results are
compared with molecular dynamics simulations to elucidate the sympathetic
cooling
mechanism and to determine crystal properties.