Lifetimes and electromagnetic transition strength in 124Ba

Mariya Trichkova,Christoph Fransen,Alfred Dewald,Andrey Blazhev,Claus Müller-Gatermann,Marcel Beckers,Georgi Rainovski,Desislava Kalaydjieva,Jan Jolie,Karl-Oskar Zell,Kalin Gladnishki

doi:10.1051/epjconf/201819403004

Mariya Trichkova, Christoph Fransen + Show 9 more

Open Access

https://doi.org/10.1051/epjconf/201819403004

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Abstract

Lifetimes of excited states of 124Ba were measured by the Recoil Distance Doppler Shift (RDDS) technique. The γ-ray coincidence data were analysed by the Differential Decay Curve method (DDCM). The trend of the experimentally deduced normalized B(E2) values reveals a drop at the 8+1 state, which may be caused by structural changes in the backbending region.

Highlights

Barium isotopes are subject of considerable interest, because of a variety of structural phenomena observed in them
For each level of interest the properly normalized intensities of the shifted (Is) and unshifted (Iu) components of the deexciting transition were determined from coincidence spectra with the shifted component of a transition directly populating the state for each distance
According to the Differential Decay Curve method (DDCM), if the level of interest is populated by transition B and it is depopulated via transition A, in the special case of gating on the Doppler-shifted component of the direct feeding transition (B), the mean lifetime τ can be derived for each target-to-stopper distance by applying the following equation: τi(x) where v denotes the recoil velocity

Summary

Introduction

Barium isotopes are subject of considerable interest, because of a variety of structural phenomena observed in them. In addition to high-spin phenomena, γ-bands have been observed. Their notable feature is the strong staggering of the excitation energies. At spin 10+ the ground state band of 124Ba splits into two bands due to alignment of a pair of protons and neutrons in the h11/2 orbitals at rotational frequencies 0.37 and 0.41 MeV, respectively. Possible configurations of these bands were discussed earlier using the cranked shell model [5, 7, 8]. The X(5) model provides parameter free prediction for the level scheme and B(E2) transition strengths

Experimental details

Data analysis and preliminary results

Iπ Eγ τ

The data was analyzed by using the computer program

Findings

Summary