Experiments With Potassium Isotopes

Abstract

Experiments on cooling and trapping of potassium are strongly motivated by the occurrence of three isotopes: K, K, K with a relative abundance of 93.26%, 0.012% and 6.73%, respectively. K and K are bosons while K is a fermion, therefore potassium is a good candidate to study a degenerate dilute Fermi gas and bosons-fermions mixtures. A quantum degenerate trapped gas of fermions is relatively unexplored both theoretically and experimentally. The first onset of Fermi degeneracy in a trapped atomic gas of K has been very recently reported by B. DeMarco and D. Jin. They were able to cool a sample of fermionic potassium atoms down to 0.5 ( is the Fermi temperature). A sample of trapped quantum degenerate fermions will provide the opportunity to investigate fundamental physical phenomena eventually including pairwise correlation, analogous to Cooper pairing of electrons, and BCS transition to the superfluid state in fermionic system with attractive interactions. The experimental method to achieve quantum degeneracy in a sample of alkali-metal atoms, consists of two different cooling stages. In the first one laser cooling techniques allow to gain many orders of magnitude in the phase space density providing a sample of atoms with The final gap in the phase space density is covered by evaporative cooling in a magnetic trap. To be effective this cooling process requires a high enough ratio between elastic and inelastic collision rates In the case of potassium the laser cooling process is affected by the peculiar features of the