80Se(n,γ) cross-section measurement at CERN n TOF

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

doi:10.1088/1742-6596/1668/1/012001

Abstract

Radiative neutron capture cross section measurements are of fundamental importance for the study of the slow neutron capture (s-) process of nucleosynthesis. This mechanism is responsible for the formation of most elements heavier than iron in the Universe. Particularly relevant are branching nuclei along the s-process path, which are sensitive to the physical conditions of the stellar environment. One such example is the branching at 79Se (3.27 × 105 y), which shows a thermally dependent β-decay rate. However, an astrophysically consistent interpretation requires also the knowledge of the closest neighbour isotopes involved. In particular, the 80Se(n,γ) cross section directly affects the stellar yield of the “cold” branch leading to the formation of the s-only 82Kr. Experimentally, there exists only one previous measurement on 80Se using the time of flight (TOF) technique. However, the latter suffers from some limitations that are described in this presentation. These drawbacks have been significantly improved in a recent measurement at CERN n TOF. This contribution presents a summary of the latter measurement and the status of the data analysis.

Highlights

Regarding previous data, there exists only one previous time of flight (TOF) measurement on 80Se, which helped to constrain the physical conditions of the weak s-process [4]
The neutron flux was monitored with a 6Li foil intercepting the beam, and 3H products of the 6Li(n,α) reaction were measured by using a silicon monitor placed off-beam
The n TOF experimental weighted count rate as a function of the neutron energy is shown in Fig. 2 with an arbitrary scale

Summary

Introduction

There exists only one previous TOF measurement on 80Se, which helped to constrain the physical conditions of the weak s-process [4]. Cross section data was obtained only beyond neutron energies of ∼3 keV This prevented the measurement of one large s-wave resonance in the keV-region. While these resonances could barely affect the nucleosynthesis during the hot conditions of shell-carbon burning, they can play a crucial role during core He-burning, where temperatures of ∼ 30 keV are reached. A second limitation of the previous experiment concerns the low energy resolution, which is due to the 60 cm flight-path used [4]. An assessment of possible neutron-sensitivity deviations in our or previous experiments will be made in future stages of the data analysis

Methods

Results

Conclusion