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Spectroscopy with laser-cooled francium and progress on atomic parity non-conservation

May 18, 2015 - 2:00pm
Jiehang Zhang

Francium, due to its rareness and short-lived radioactivity, has always been the least understood alkali atom. Despite its scarcity, the large nucleus charge yields enhancements to various effects related to fundamental symmetry tests. The Francium Parity Non-Conservation (FrPNC) collaboration aims at measuring weak-interaction manifestations in a low energy system: the francium atom. We have successfully commissioned the apparatus at TRIUMF, the Canadian national lab for nuclear and particle physics. The work reported in this thesis details the construction of the Francium Trapping Falicity (FTF), which employs high efficiency laser-cooling and trapping of francium from the accelerator. We further demonstrate atom transfer into a precision trap, where the electromagnetic field environment can be exquisitely controlled. Two experimental programs of measuring atomic PNC will take place, aimed at probing the weak charge of the nucleus and the parity violating nuclear anapole moment, respectively. We perform precision 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 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.

Advisor: Prof. Luis Orozco

Dr. William Phillips
Dr. Trey Porto
Dr. Gene Sprouse
Dr. Alice Mignerey

2136 PSC
College Park, MD 20742