“Nuclear Microscope” at Heavy Ion Laboratory in Warsaw

Speaker: Pawel Napiorkowski, Heavy Ion Laboratory, UW, Warsaw

December 10, 2021 – 15:30, FLNR conference hall

Abstract:

A development of radioactive beams facilities led to a revival of interest in the Coulomb excitation method. A construction of more efficient detection systems enabled studies of exotic nuclei, but also opened new opportunities to investigate electromagnetic structure of stable isotopes in a more profound way.
In the modern COULEX experiments very weak effects can be explored, which were not accessible before so far due to a very small cross section. These measurements yield values of individual transitional matrix elements that could be interpreted in terms of nuclear structure models. A recent experiment to study properties of the presumably super-deformed band in ⁴²Ca can be a good example.
But typically, the use of very efficient detector systems in Coulomb excitations studies of stable isotopes allows nowadays to determine sets of matrix elements large enough to perform a comprehensive analysis of nuclear deformation. The Quadrupole Sum Rules approach makes possible to deduce the quadrupole deformation parameters like it was done in the case of ¹²⁰Te.
In the analysis of contemporary COULEX experiments appropriate tools are necessary to perform a multi-parametric fit of electromagnetic matrix elements to experimental data. The GOSIA code developed by Czosnyka, Cline and Wu in the eighties of previous century remains a standard in this domain. Recent development implementing advanced computer technologies, namely genetic algorithms, will help to obtain more reliable results in a faster way.
The possibility of model-independent determination of nuclear deformation and its dynamics is like seeing atomic nuclei under a microscope – this is the important advantage of the modern Coulomb excitation technique.