Christoph Düllmann, GSI & Johannes Gutenberg-University Mainz
Superheavy elements: their production, nuclear and atomic properties, and how to go beyond Z=118
Argonne Physics Division Colloquium - 16 Mar 2017
11:00 AM, Building 203 Auditorium

Studies of the superheavy elements have been a pillar of the research program at the GSI Darmstadt for decades. I will give an introduction to the field and show recent highlights of the richness of the GSI program, which includes studies on their synthesis and nuclear structure, but also their atomic physics including optical spectroscopy and high precision mass measurements. The new elements with Z=113, 115, 117, and 118 were recently officially accepted and named by the IUPAC. Using 48Ca-induced fusion reactions on actinide targets is the dominant pathway to elements with Z≥112, but this is exhausted at Z=118 due to the lack of suitable target materials with sufficiently high proton number to reach elements beyond Z=118. To search for yet heavier elements, experiments with a total running time of over one year were performed at GSI and FLNR so far, studying five different reactions leading to Z=119 and 120. I will use the 50Ti + 249Cf reaction, leading to Z=120 and studied at the gas-filled recoil separator TASCA, to illustrate the current status on the experimental as well as the theoretical side. The latter is of crucial importance to give proper guidance to experimentalists. Besides more detailed studies of fusion reactions, complementary studies both experimentally as well as theoretically focusing on entrance channel phenomena like quasifission appear ideal to give better guidance to future search experiments for new elements. I will conclude with an outlook including the developments at HIM Mainz and GSI Darmstadt towards the construction of a new superconducting linac for SHE studies.

Argonne Physics Division Colloquium Schedule