Astatine - the rarest element on Earth: From laser spectroscopy to fundamental atomic properties

Wednesday 31 Jan 2018, 14:30 → 15:15 Europe/Zurich

26/1-22 (CERN)

The radioactive element astatine (At) is the rarest naturally occurring element on Earth. 

Certain isotopes of this enigmatic element possess decay characteristics, which make them particularly suitable for cancer treatment through targeted alpha therapy.  

Natural astatine exists predominantly in the form of 218At (t1/2 = 2 s), with an abundance that is maintained by the radioactive decay of natural 238U, but its scarcity prohibits the use of these atoms for the study of even basic properties of the element.  Instead, artificial production of astatine isotopes through nuclear reactions is required to obtain samples large enough for study of its atomic properties in the laboratory.  Of primary interest for our study are the ionization energy and electron affinity. These two fundamental characteristics determine the bond strengths and therefore the chemical behaviour of astatine.

The ongoing experimental programme to measure these two properties of astatine at the ISOLDE radioactive isotope facility at CERN will be presented.