Speaker
Description
Collinear laser spectroscopy provides a sensitive probe of hyperfine interactions, electromagnetic moments, and isotope shifts in short-lived nuclei. In particular, radioactive sodium isotopes provide a useful testing ground for nuclear-structure studies as well as precision tests of atomic calculations.
In this presentation, I will present recent collinear laser spectroscopy measurements of $^{21}$Na and $^{23}$Na performed at the CLaSsy beamline of the RAON ISOL facility in Korea, with a focus on the hyper-fine structure measurement of the neutron-deficient isotope $^{21}$Na. Sodium beams were produced from a SiC target bombarded by a 70-MeV proton beam, mass separated, accelerated to 20 keV, cooled and bunched in an RFQ cooler-buncher, and delivered to the CLaSsy beamline. After charge exchange, neutral sodium atoms were probed on the atomic D1 transition using a 589-nm laser, and fluorescence photons were detected in time coincidence with the ion bunches.
The talk will discuss the experimental method, including the use of collinear and anti-collinear geometries to control beam-energy-related systematics. The stable isotope $^{23}$Na was measured as a reference to validate the spectroscopic analysis and evaluate systematic effects. I will then present the hyperfine-structure analysis of $^{21}$Na, focusing on the extraction of the magnetic-dipole hyperfine constants A(3s2S1/2) and A(3p2P1/2). The results are compared with previous measurements and with relativistic coupled-cluster calculations, providing a benchmark for higher-order electron-correlation effects. The outlook for future isotope-shift and charge-radius measurements of $^{21}$Na at RAON will also be discussed.