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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-23 17:56 |
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Conference: Bucharest University Faculty of Physics 2022 Meeting
Section: Theoretical Physics and Applied Mathematics
Title:
Improved calculation of electron capture decay ratios
Authors:
Vasile Alin SEVESTREAN
*
Affiliation:
1) Centre International de Formation et de Recherche Avancées en Physique, Magurele, Romania
2) Horia Hulubei National Institute for R&D in Physics and Nuclear Engineering, Magurele, Romania
3)Faculty of Physics, University of Bucharest, Magurele, Romania
E-mail
sevestreanalin@yahoo.com
Keywords:
Electron Capture; Phase-space factors
Abstract:
Electron capture on nuclei plays an important role in several domains which include, but are not limited to, astrophysics (core-collapse, thermonuclear supernova), medicine ( I-123 as a tracer to thyroid imaging), nuclear waste (Ca-41).
Although the electron capture is known for over 80 years now, there is a need for improvement of the decay rate calculation due to their errors with respect to the experimental data. The decay rate contains two distinct parts: the nuclear matrix elements, which involve the nuclear structure of the parent and daughter nuclei and electron phase-space factors, which are described by the
dynamics of the captured electron.
My work focuses on the improvement of the calculation of electron phase-space factors. I used a more accurate electron wave function for the bound electrons obtained as a self-consistent solution of the Dirac-Hartree-Fock-Slater equations for the initial and final atoms (the excited configuration of the final atom was taken into account). The wave function was obtained with a slightly modificated version of the Fortran subroutine package RADIAL. For that, several codes in Wolfram Mathematica and Shell Scrip were implemented.For better results, the exchange and overlap correction was introduced using the Vatai's approach. The calculation was performed for allowed and forbidden unique beta transitions. To have a direct comparison with the experimental data, I computed the decay probability ratios for electron captures from different electronic shells, which are independent of the nuclear structure effects.
The present work opens the path to extend the computation of the electron capture rates for many other nuclei that undergo allowed and forbidden unique beta decays and to include other corrections related to the accurate calculation of the phase space factors.
References:
1) Francesc Salvat et al., Computer Physics Communications 240 (2019) 165-177
2) Sabin Stoica et al., Advances in High Energy Physics 2016 (2016)
3) Jameel-Un Nabi et al., Universe 6 (2020)
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