New techniques of laser spectroscopy on exotic isotopes of gallium and francium

The neutron-deficient gallium isotopes down to ${N}$=32 have had their hyperfine structures and isotope shifts measured via collinear laser spectroscopy using the COLLAPS (COllinear LAser sPectroScopy) beam line. The ground-state spin of $^{63}$Ga has been determined as ${I}$ = 3/2 and its magnetic dipole and electric quadrupole moments were measured to be $\mu$ = +1.469(5) $_{\mu N}$ and ${ Q}$s = +0.212(14) b respectively. The nuclear moments of $^{70}$Ga were measured to be ${\mu}$= +0.571(2) $_{\mu}$ and ${Q}$s = +0.105(7) b. New isotope shift results were combined with previously measured values of the neutron-rich isotopes and the changes in mean-square charge radii of the entire gallium isotope chain were investigated. Analysis of the trend in the neutron-deficient charge radii demonstrated that there is no evidence of anomalous charge radii behaviour in gallium in the region of ${N}$=32. A sudden increase of the charge radii was observed at the ${N}$=50 shell gap and an inversion of the normal odd-even staggering effect was seen at ${N}$=40.The development of the CRIS (Collinear Resonant Ionisation Spectroscopy) beam line is reported, detailing the components that have been installed since its proposal in 2008. Results from the first experimental campaign on francium are discussed to present the current operational status of CRIS. Initial results demonstrate an experimental efficiency of 1:70, collisional background rate of 1:10$^{5}$ and a resolution of 1.5 GHz. Analysis of the $^{221}$Fr data provided an experimental accuracy of measurements using CRIS, with 44 MHz for the ${ A}(7s\, ^2\!S_{1/2})$ hyperfine coefficients and 360 MHz for the isotope shifts. The ${A}(7s\, ^2\!S_{1/2)}$ hyperfine coefficients and isotope shifts were measured for $^{207,211,220,221}$Fr and show good agreement with literature values. The isotope shifts were combined with literature values to determine the atomic factors for the $7s \,^2\!S_{1/2} \rightarrow 8p \,^2\!P_{3/2}$ atomic transition so that changes in the mean-square charge radii could be extracted and compared with literature. The results demonstrate the successful commissioning of the CRIS experiment.