Eur. Phys. J. D 51, 173-177 (2009)
https://doi.org/10.1140/epjd/e2009-00001-5

Measurement of the trapping lifetime close to a cold metallic surface on a cryogenic atom-chip

¹ Laboratoire Kastler Brossel, ENS, CNRS, UPMC, 24 rue Lhomond, 75231 Paris Cedex 05, France
² Collège de France, 11 place Marcelin Berthelot, 75231 Paris Cedex 05, France

Corresponding authors: ^a emmert@lkb.ens.fr - ^b gilles.nogues@lkb.ens.fr

Received: 3 November 2008
Published online: 16 January 2009

Abstract

We have measured the trapping lifetime of magnetically trapped atoms in a cryogenic atom-chip experiment. An ultracold atomic cloud is kept at a fixed distance from a thin gold layer deposited on top of a superconducting trapping wire. The lifetime is studied as a function of the distances to the surface and to the wire. Different regimes are observed, where loss rate is determined either by the technical current noise in the wire or the Johnson-Nyquist noise in the metallic gold layer, in good agreement with theoretical predictions. Far from the surface, we observe exceptionally long trapping times for an atom-chip, in the 10 min range.