Eur. Phys. J. D 23, 409-413 (2003)
https://doi.org/10.1140/epjd/e2003-00059-y

Comparative investigation of ³⁹K and ⁴⁰K trap loss rates: alternative loss channel at low light intensities

¹ INFM and European Laboratory for Non-linear Spectroscopy, Universitá di Firenze, Largo E. Fermi 2, 50125 Firenze, Italy
² Instituto de Física de São Carlos, Universidade de São Paulo CP 369, 13560-970 São Carlos-SP, Brazil

Corresponding author: ^a marcassa@if.sc.usp.br

Received: 1 May 2002
Revised: 19 October 2002
Published online: 4 March 2003

Abstract

We report a comparative investigation of trap loss rates in a magneto-optical trap for two potassium isotopes, ³⁹K and ⁴⁰K, as a function of trap light intensity. The isotopes present a quite similar behavior for the loss rates at high intensities, and a sudden increase of the loss rates at low intensities is present in both cases. While for ³⁹ K such increase can be explained assuming that the major contribution to the losses comes from hyperfine changing collisions, a different loss mechanism must be considered for ⁴⁰K, which has an inverted ground state hyperfine structure. The experimental results of both isotopes are well reproduced by an alternative model based on radiative escape as the dominant loss mechanism.