Theoretical and experimental work leads to a redetermination of the Th-229 isomer charge radius

Marianna Safronova and colleagues from the Univ. of Delaware and from the Kurchatov Institute in St. Petersburg have performed new atomic structure calculations for Th+and Th2+that are used to relate measured spectroscopic isotope shifts to differences of the nuclear charge radii. Such calculations are notoriously difficult for these thorium ions because of strong configuration mixing of the electrons. Combined with experimental data on isotope shifts in Th+from 227Th to 232Th, measured at KfK Karlsruhe in 1989, and the recent results on isotope shifts of Th2+obtained by PTB and LMU within nuclock, they provide a more reliable picture of the thorium nuclear charge radii, including an improved value for the radius change between 229Th and the229mTh isomer: Excitation to the isomeric state increases the charge radius by less than 0.02%. The work is published in Physical Review Letters.


Adriana Pálffy-Buß is awarded the prestigeous Herta-Sponer-Prize from the German Physical Society (DPG) for her pathfinding reasearch on quantum effects in the interaction of atomic nuclei with X-ray pulses. Here‘s the link to the press release. Congratulations Adriana!

Tomas Sikorsky joins TU Wien Thorium Team

Starting with October 22., Tomas Sikorsky is enforcing the TU Wien Thorium team. Tomas has worked on NMR during his masters and on ion collisions with ultra cold gasses during his PhD in the team of Roee Ozeri at Weizmann. In Vienna, he will establish detection of the Thorium isomer via nuclear quadrupole resonance spectroscopy (NQRS). Welcome Tomas!