Berlin 2001 – wissenschaftliches Programm

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A: Atomphysik

A 2: Ion Scattering I

A 2.1: Vortrag

Montag, 2. April 2001, 15:45–16:00, H1028

Laser-trapped atoms as a precision target for storage rings — •B. Eike¹, U. Eisenbarth¹, R. Grimm², F. Herrmann¹, J. Kleinert¹, D. Schwalm¹, and M. Weidemüller¹ — ¹Max-Planck-Institut für Kernphysik, 69029 Heidelberg, Germany — ²Institut für Experimentalphysik, Universität Innsbruck, Austria

We present the first realization of a target in a storage ring which is based on ultracold atoms in a laser trap. This target combines two unique features: It is a novel diagnostic tool for weak ion beams and enables high-precision studies of ion-atom collisions at high c.m. energies. Cesium atoms at a temperature below 100 µK are confined in a magneto-optical trap [1] which is installed in the Heidelberg Test Storage Ring. The position of the atomic cloud (dia. 100µm) can be controlled horizontally and vertically by static magnetic fields over a range of 20 mm.

Interactions between the ion beam and the target are monitored sensitively by losses of trapped atoms. The influence of the target on the storage time and the closed orbit of the ion beam is negligible. The target was applied to measure the profile of a stored C⁶⁺ ion beam (74 MeV) with high resolution down to currents of 50 nA and to determine accurately the total cross section for Cs-C⁶⁺ trap-loss collisions.

In order to distinguish between different ion-atom collision processes an ion detector will be installed. The laser-cooled target is suited ideally to implement recoil ion momentum spectroscopy [2] for a broad variety of detailed studies of ion-atom interactions.

[1] B. Eike et al., NIM A 441 (2000) 81.

[2] J. Ullrich et al., J. Phys. B 30 (1997) 2917.