January 26, 2018, 12:00 PM, 112W
Marija Vostinar (University of Tennesse)
Superheavy elements and decay spectroscopy of 258Db
How many elements are there? How many isotopes exist? These questions are still a source of extensive scientific investigations. Today, we have a complete subfield of nuclear physics which is dedicated to the formation, identification and study of the heaviest elements and their isotopes. Even recently, in 2016, four new elements have been named steering the interest of complete physics community [1].The purpose of this talk is to introduce the subfield of heavy and superheavy element investigations: the scientific interests, benefits, difficulties and inventions. Knowing the heaviest element which can exist will give us significant input on the nuclear force and its equilibrium with the Coulomb force responsible for the stability and existence of the nucleus and elements in extension. As an example, before the existence of the shell model it was thought, based on the macroscopic model predictions that no elements heavier than Z=100 can exist. With the technological developments it was soon showed that the element with Z=100, fermium [2] can be produced and it is stable against fission. Soon enough heavier elements were discovered and increased the interest in the topic. New questions appeared: Why do they exists? Is there a new/next shell closure? Where is this shell closure? What is the heaviest element which can be produced? Today, almost 60 years since the discovery of Fm we still try to answer these questions. The technology has improved; the limits are pushed but the science still faces difficulties. The detailed studies are available only in the region [3] of light heavy and superheavy elements while the heaviest isotopes are still a mystery. As an example for these investigations, spectroscopic study of the structure of 258Db (Z=105) will be given [4].
[1] P. J. Karol et al., Pure Appl. Chem. Vol 88, no 1-2, (2016).
[2] A. Ghiorso et al., Phys. Rev. Vol 99, no 3, 1048-1049, (1955).
[3] M. Asai et al., Nucl. Phys. A, Vol 944, 308-332, (2015).
[4] M. Vostinar, PhD Thesis University of Caen-Normandie, (2015).