In-source laser spectroscopy with the laser ion source and trap; First direct study of the ground-state properties of Po

レーザーイオン源内核分光で明らかにしたPoの基底状態の性質

Fink, D. A.*; Cocolios, T. E.*; Andreyev, A. N.; Antalic, S.*; Barzakh, A. E.*; Bastin, B.*; Fedorov, D. V.*; Fedosseev, V. N.*; Flanagan, K. T.*; Ghys, L.*; Gottberg, A.*; Huyse, M.*; 今井 伸明*; Kron, T.*; Lecesne, N.*; Lynch, K. M.*; Marsh, B. A.*; Pauwels, D.*; Rapisarda, E.*; Richter, S. D.*; Rossel, R. E.*; Rothe, S.*; Seliverstov, M. D.*; Sjdin, A. M.*; Van Beveren, C.*; Van Duppen, P.*; Wendt, K. D. A.*

Fink, D. A.*; Cocolios, T. E.*; Andreyev, A. N.; Antalic, S.*; Barzakh, A. E.*; Bastin, B.*; Fedorov, D. V.*; Fedosseev, V. N.*; Flanagan, K. T.*; Ghys, L.*; Gottberg, A.*; Huyse, M.*; Imai, Nobuaki*; Kron, T.*; Lecesne, N.*; Lynch, K. M.*; Marsh, B. A.*; Pauwels, D.*; Rapisarda, E.*; Richter, S. D.*; Rossel, R. E.*; Rothe, S.*; Seliverstov, M. D.*; Sjdin, A. M.*; Van Beveren, C.*; Van Duppen, P.*; Wendt, K. D. A.*

A Laser Ion Source and Trap (LIST) for a thick-target, isotope-separation on-line facility has been implemented at CERN ISOLDE for the production of pure, laser-ionized, radioactive ion beams. The first physics application of the LIST enables the suppression of francium contamination in ion beams of neutron-rich polonium isotopes at ISOLDE by more than 1000 with a reduction in laser-ionization efficiency of only 20. Resonance ionization spectroscopy is performed directly inside the LIST device, allowing the study of the hyperfine structure and isotope shift of Po for the first time. Nuclear decay spectroscopy of Po is performed for the first time, revealing its half-life, -to--decay branching ratio, and -particle energy. This experiment demonstrates the applicability of the LIST at radioactive ion-beam facilities for the production and study of pure beams of exotic isotopes.