Speaker
Dr
Mikael Reponen
(RIKEN)
Description
The nucleus perturbs the atomic energy levels of atoms and ions at the ppm level and
although this is a small absolute effect it is readily probed and measured by modern
laser spectroscopic methods. These methods are particularly suitable for the study of
short-lived radionuclides with lifetimes as short as a few milliseconds and production
rates often only a few isotopes/isomers per second in the case of resonance laser ionization
spectroscopy (RIS)[1]. This ionization technique, which utilizes stepwise excitation of the
unique atomic state of different elements, has been demonstrated to be a powerful tool
for probing nuclei far from stability[2, 3].
The analysis of the RIS hyperfine spectra is typically performed with the help of
relative intensities calculated using angular momentum coupling. The analysis yields the
nuclear magnetic dipole and electric quadrupole moments and changes in mean-square
charge radii in a model-independent manner. However, recent studies have observed that
the relative intensities of the measured hyperfine transitions do not necessarily follow the
calculated intensities. This has partially been attributed to optical pumping effects which
are not addressed by the typical procedures. Due to this new methods, based on modeling
the complete ionization process [4], are required to restrict the number of free parameters
during analysis.
Here we present a model for resonance ionization process based on rate-equations as
a stepping stone towards a density matrix -based model. The software is written in C++
utilizing Boost Odeint, Eigen and Sundials -libraries. In addition, the software facilitates
parallel solving capabilities through the OpenMP library.
[1] T. Cocolios et al., Phys. Rev. Lett. 103,(2009), 102501
[2] R. Ferrer et al., Phys.Lett. B 728, (2014), 191
[3] S. Rothe et al., Nat.Commun.4, (2013), 1835.
[4] S. Gheysen et al., Phys Rev C 69, (2004), 064310
Primary author
Dr
Mikael Reponen
(RIKEN)
Co-author
Mr
Volker Sonnenschein
(University of Jyväskylä)
