Speaker
Description
Zixuan Yue - University of York, on behalf of LOI219, RILIS and IDS collaborations
It is well-known that there is a kink in nuclear charge radii when crossing the magic number N=126. This phenomenon has been observed in the Hg(Z=80), Pb (Z=82) and Bi (Z=83) isotopes [1]. At present, the charge radii of Tl (Z=81) isotopes are only known up to 208Tl (N=127). In order to observe such a kink for the Tl chain, the isotope shift (IS) and hyperfine structure (hfs) of heavier isotopes needs to be measured. However, production of pure heavy Tl isotopes is hampered by strong Fr isobaric contamination.
During the April 2022 LOI219 experiment, a collaborative effort was made by the RILIS and IDS teams to measure the IS/hfs of Tl isotopes from 205Tl to 209Tl (N=124-128). The RILIS in LIST mode was applied to suppress Fr contamination. Counting of photo-ions was made by Faraday cup and IDS. For the first time, IS/hfs has been measured for 209Tl establishing the kink at N=126 for the Tl isotopic chain. In addition, the first measurement of the magnetic moment and charge radius for the 11/2- isomeric state of 207Tl has been achieved. In this contribution, results on the HFS/IS of the 207-209Tl isotopes, as well as some preliminary data on charge radii and magnetic moments, will be presented.
[1]: Day Goodacre, T. et al. “Laser Spectroscopy of Neutron-Rich 207,208Hg Isotopes: Illuminating the Kink and Odd-Even Staggering in Charge Radii across the N=126 Shell Closure.” Physical review letters 126 3 (2021): 032502.
