An experiment performed in the Accelerator Laboratory of University of Jyväskylä, Finland, has succeeded in producing a previously unknown atomic nucleus, 190-Astatine, consisting of 85 protons and 105 neutrons. The nucleus is the lightest isotope of astatine discovered to date.

Astatine is a fast-decaying, and therefore rare element. It has been estimated that in the Earth's crust there is no more than one tablespoon of astatine. 190-Astatine, the new isotope, was produced in the fusion of 84Sr beam particles and silver target atoms. The isotope was detected among the products by using the detectors of a RITU recoil separator.

New nucleus emits alpha particles

The new nuclei decay via alpha decay towards more stable isotopes. Alpha decay is a common decay mode of heavy nuclei.

"The studies of new nuclei are important for understanding the structure of atomic nuclei and the limits of known matter," says Doctoral Researcher Henna Kokkonen from the Department of Physics, University of Jyväskylä.

The new discovery was made by Kokkonen, who recently graduated with a Master of Science degree. The study was a part of her master's thesis, and the research is published in the journal Physical Review C.

"In my thesis, I analyzed experimental data among which the new isotope was found. During my thesis process and summer internships I got to know the Nuclear Spectroscopy group's work. Now I am very happy to work in the group towards my Ph.D. degree," says Kokkonen.