Laser spectroscopy on germanium isotopes at COLLAPS-CERN

by Tassos Kanellakopoulos (KU Leuven (BE))

Wednesday 5 Jun 2019, 14:15 → 15:00 Europe/Zurich

Following earlier studies of the Zn (Z = 30) and Ga (Z = 31) isotopic chains [1, 2, 3, 4], the nuclei of germanium (Z = 32) can provide a useful insight into the nuclear shell evolution of the N = 40 subshell closure by adding protons beyond the Z = 28 closed shell. At the same time, the inverted odd-even staggering effect observed for the first time on Kr (Z = 36), Rb (Z = 37) and Sr (Z = 38) [5] and recently also on Ga isotopes [6], makes the Ge isotopic chain a good case to study the evolution of this phenomenon as the proton number increases.

Using the collinear laser spectroscopy technique at the COLLAPS beamline located at ISOLDE-CERN, the hyperfine spectra of the 68-74Ge around N = 40 were probed in order to extract nuclear spins, electromagnetic moments and changes in the mean-square charge radii. For this study, the 4s24p2 3P1 - 4s24p5s 3P1 (269 nm) atomic transition of Ge atom was used. The production of laser light with this wavelength is challenging with cw Ti:Sa and dye lasers and required the installation of a frequency mixing unit. In this contribution, preliminary results of the ground state structure of 68-74Ge will be presented together with details of the newly installed laser system.

 

 

[1] B. Cheal et al., Phys. Rev. Lett. 104, 252502 (2010)
[2] C. Wraith et al., Phys. Lett. B 771, pp. 385-391 (2017)
[3] X.F. Yang et al., Phys. Rev. Lett. 116, 219901 (2016)
[4] X.F. Yang et al., Phys. Rev. C 97, 044324 (2018)
[5] P. Lievens et al., EPL 33 11 (1996)
[6] T. J. Procter et al., Phys. Rev. C 86, 034329 (2012)