Heidelberg 1999 – scientific programme

Parts | Days | Selection | Search | Downloads | Help

A: Atomphysik

A 18: Symposium Hochgeladene Ionen II Poster

A 18.12: Poster

Friday, March 19, 1999, 15:00–16:30, PY

Positron and Electron Cooling of Highly Charged Ions in a Penning Trap — •J. Bernard, H.-J. Kluge, G. Marx, and W. Quint — GSI, Planck-Str. 1, D-64291 Darmstadt

Electron cooling is already largely employed in many storage rings to cool the radial motion of ion beams and this way increase the density of the phase space. It has also been used at CERN to slow down antiproton in a trap. The Hitrap project consisting of trapping highly charged ions coming from a 10 keV/q beam, positron or electron cooling could be employed to cool down the ions. The cooling time constant has been estimated with a model issued from plasma physics. It depends on both the positron/electron and ion energies (Te and Ti). By solving numerically the two coupled differential equations driving the evolution of Te and Ti as a function of time, we obtain that the time needed to cool down the ion is of around 4 s for protons and 0.3 s for U91+. A rapid estimation of the radiative recombination time constant has shown that this process is much slower. The conclusion is that it should be possible to use positrons or electrons to cool down the ion motion down to a few eV.