Spectroscopy with Laser-cooled Francium and Progress on Atomic Parity Non-conservation

Abstract

Francium, the heaviest alkali, possesses a unique combination of structural simplicity and great sensitivity to effects such as atomic parity non-conservation (APNC). We report in this thesis our progress towards measuring weak-interaction physics in a low energy system: the francium atom. We have built a new generation of high-efficiency laser cooling and trapping facility at TRIUMF national laboratory in Canada. We constructed a precision science chamber and demonstrate francium atom transfer into the precision trap, where the electromagnetic field environments can be exquisitely controlled such that weak-interaction studies via optical and microwave excitations can take place. We perform laser spectroscopy measurements of the hyperfine structure and isotope shifts in a chain of francium isotopes near the neutron closed shell (N = 126), including both ground and isomeric nuclear states. These measurements provide a basis for benchmarking state of the art atomic theory,

as well as future nuclear structure calculations in Fr, necessary for interpreting the weak-interaction studies. These developments lay important foundations for precision parity non-conservation measurements with francium.