Neutron capture measurement at the n TOF facility of the 204Tl and 205Tl s-process branching points

A Casanovas ,J Andrzejewski ,P J Davies ,C Lederer-Woods ,R Vlastou ,F Gunsing ,P Sprung ,A Mazzone ,M A Cortés‐Giraldo ,V Babiano-Suárez ,N V Sosnin ,L Piersanti ,R Reifarth ,O Aberle ,S Heinitz ,A Musumarra ,A Pavlik ,B Fernández-Domíngez ,I Durán ,A G Smith ,C Massimi ,Q Ducasse ,I Ladarescu ,A R Junghans ,D Schumann ,J Moreno-Soto ,D Rochman ,A Gawlik ,M Busso ,D Bosnar ,E Chiaveri ,A Manna ,J Lerendegui-Marco ,E González‐Romero ,M Krtička ,K Göbel ,M Dietz ,V Variale ,Akira Kimura ,P Schillebeeckx ,A Saxena ,S Cristallo ,F Calviño ,F Käppeler ,D Vescovi ,M Kokkoris ,R Garg ,C Domingo‐Pardo ,C Rubbia ,L Audouin ,J Perkowski ,A Ventura ,U Jiri ,S Urlaß ,V Vlachoudis ,V Furman ,S Amaducci ,L Tassan‐Got ,A Ferrari ,R Dressler ,A Tarifeño-Saldivia ,Μ Diakaki ,J Quesada ,J L Taín ,Y Kadi ,B Thomas ,E Dupont ,Y Kopatch ,P J Woods ,D Kurtulgil ,E Berthoumieux ,E Maugeri ,T Martínez ,T Wright ,G Tagliente ,N Colonna ,D Ramos ,L A Damone ,I Porras ,G Cortés ,N Patronis ,F Mingrone ,G Vannini ,M A Millán-Callado ,M Calviani ,C Guerrero ,Z Eleme ,A Wallner ,S Gilardoni ,M Bacak ,Paolo Milazzo ,I Knapová ,D G Jenkins ,E Jericha ,V Michalopoulou ,P Žugec ,A Stamatopoulos ,S Bennett ,A Masi ,L Cosentino ,M Sabaté-Gilarte ,M Mastromarco ,E Pirovano ,A Negret ,P Torres-Sánchez ,J Praena ,I Ferro-Gonçalves ,F Cerutti ,A Sekhar ,D Cano‐Ott ,P Mastinu ,M Caamaño ,S J Lonsdale ,M Barbagallo ,J Balibrea ,A Tsinganis ,P Vaz ,L Caballero ,A Mengoni ,A Oprea ,V Alcayne ,C Petrone ,E Mendoza ,J Heyse ,D Macina ,A Brown ,P Finocchiaro ,S Valenta ,F Ogállar ,U Köester

doi:10.1088/1742-6596/1668/1/012005

Abstract

Neutron capture cross sections are one of the fundamental nuclear data in the study of the s (slow) process of nucleosynthesis. More interestingly, the competition between the capture and the decay rates in some unstable nuclei determines the local isotopic abundance pattern. Since decay rates are often sensible to temperature and electron density, the study of the nuclear properties of these nuclei can provide valuable constraints to the physical magnitudes of the nucleosynthesis stellar environment. Here we report on the capture cross section measurement of two thallium isotopes, 204Tl and 205Tl performed by the time-of-flight technique at the n TOF facility at CERN. At some particular stellar s-process environments, the decay of both nuclei is strongly enhanced, and determines decisively the abundance of two s-only isotopes of lead, 204Pb and 205Pb. The latter, as a long-lived radioactive nucleus, has potential use as a chronometer of the last s-process events that contributed to final solar isotopic abundances.

Highlights

Half of the solar elemental abundances heavier than iron are produced by the so-called s-process of stellar nucleosynthesis
The usual path of the nucleosynthesis process is changed, which affects the abundances of stable nuclei immediately following the unstable species
In this work we present the neutron capture experiments on 204Tl and 205Tl performed at the n TOF facility at CERN, in the neutron energy range of astrophysical interest (1 eV to 100 keV)

Summary

Introduction

Half of the solar elemental abundances heavier than iron are produced by the so-called s-process of stellar nucleosynthesis This is characterized by successive neutron capture and beta decay reactions, following the path of the valley of stability. In the recurrent TP episodes, the convective flash fusion of the accumulated He-shell during the interpulse rises the temperature up to ∼ 3 · 108 K (corresponding to kT ∼ 26 keV) This enables the release of neutrons by the partial activation of the 22Ne(α,n) reaction. The high temperature reached during the TP can enhance the decay of this nuclei, changing considerably their capture-to-decay ratio When this occurs, the usual path of the nucleosynthesis process is changed, which affects the abundances of stable nuclei immediately following the unstable species. The experiments were carried out in 2015 and 2018, respectively

Samples

Measurement and analysis methods

Findings

Preliminary results and outlook