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“Complete spectroscopy” of “Complete spectroscopy” of

“Complete spectroscopy” of - PowerPoint Presentation

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“Complete spectroscopy” of - PPT Presentation

31 S for nuclear astrophysics α 28 Si test experiment IFINHH IC Stefanescu 12 AI Chilug 12 L Trache 1 A Spiridon 1 D Tudor 12 N M ă rginean 1 A Turturică ID: 778611

school nuclear march astrophysics nuclear school astrophysics march 2019 31s mev amp 28si reaction preliminary resultsrussbach neutron cost chetec

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Slide1

“Complete spectroscopy” of 31S for nuclear astrophysicsα+28Si test experiment @ IFIN-HH

I.C. Stefanescu1,2, A.I. Chilug1,2, L. Trache1, A. Spiridon1, D. Tudor1,2, N. Mărginean1, A. Turturică1, L. Stan1, D. Filipescu1, N. Florea1, C. Costache1, S. Ujeniuc1, E. Radu11 Horia Hulubei National Institute for R&D in Physics and Nuclear Engineering (IFIN-HH)2 University of Bucharest, Doctoral School of Physics, Bucharest, Romania

Slide2

Astrophysical scenarioClassical novae: binary system where hydrogen-rich material accretes on a white dwarf from its low-mass main-sequence companionThermonuclear runaway ↔ proton reactions ↔ many important reactions are dominated by

resonant capture…BUT…what is the reaction rate?A(p,γ)B - the ones that count for nucl. astrophysics take place in Gamow windowResonant capture contribution to the reaction rate:Russbach School on Nuclear Astrophysics, 10 - 16 March 2019

Slide3

Astrophysical scenarioLarge uncertainties and large variations in the end products of the nova outbursts30P(p,γ)31S

– the most important reaction in novae nucleosynthesis; bottleneck passing point beyond sulphur elementsCapture is dominated by resonances – excited states in 31SDifficult to study directlySolution: use different methods 28Si(α,nγ)31S Study of the spectroscopy of the 31S nucleus at Eex ~ 7 MeV (Sp=6.13 MeV)! Keep an eye on spins & paritiesRussbach School on Nuclear Astrophysics, 10 - 16 March 2019The excited states in the region of interest are not well knownROI (considering different scenarios about novae temperatures): 6.13 MeV ↔ 7 MeV

Slide4

Previous work on 30P(p,γ)31S

2009@IFIN-HH2012@GammaSPHERERussbach School on Nuclear Astrophysics, 10 - 16 March 2019Only HPGe detectorsα+28Si  31S+n+γDoherty et al., “Key resonances in the 30P(p,γ)31S Gateway Reaction for theProduction of Heavy Elements in One Novae”, PRL 108

, 262502 (2012)

I. Stefanescu

, “A detection system for very low energy

β

-delayed proton decay”

, FAIRNESS 2017

β

-delayed proton decay of

31

Cl @TAMU

spectrum gated on 1249keV transition

Slide5

2018 ExperimentReaction: α+28Si @ E

α=22 MeV & Iα=1 pnANatural Si target; 0.57mg/cm2 deposited on 4.29mg/cm2 Ta – problems due to contaminants 29Si & 30SiReaction channel of interest: 28Si(α,nγ)31SMain goals: Populate low-spin excited states in 31S, in the region of interesthave a good discrimination in neutron detectors, between neutrons and gammasidentify good neutron – gamma coincidencesidentify γ rays in region Eex=6.13 – 7 MeV, that decay directly to ground stateExperimental set-up – 9MV Tandem Accelerator + RoSPHERE detector array: 20HPGe + 5 neutron detectors  only 18

HPGe functional during experiment

2 weeks of beam

Energy calibration done with

152

Eu &

13

C(

α

,n

γ

)

16

O reaction – enriched

13

C target, 31mg/cm

2

Russbach

School on Nuclear Astrophysics, 10 - 16 March 2019

New!!!

Use

HPGe

+ neutron detectors

Slide6

Experimental set-upRussbach School on Nuclear Astrophysics, 10 - 16 March 2019

Slide7

Very, very preliminary resultsRussbach School on Nuclear Astrophysics, 10 - 16 March 2019

Energycounts16O, 6128 keV,s-escape, d-escape13C, 3684 & 3853 keV40K

Slide8

Very, very preliminary resultsRussbach School on Nuclear Astrophysics, 10 - 16 March 2019

31S, 1249 keV31P, 1266 keVEnergycounts

Slide9

Very, very preliminary resultsRussbach School on Nuclear Astrophysics, 10 - 16 March 2019

countsEnergy31S, 1249 keV31P, 1266 keV

Slide10

Very, very preliminary resultsRussbach School on Nuclear Astrophysics, 10 - 16 March 2019

countsEnergy31S, 6138?! keVFuture plans: nov 2019, a new experiment – 28Si isotopic pure target

Slide11

Thank you for your patience Russbach School on Nuclear Astrophysics, 10 - 16 March 2019

Slide12

COST Acknowledgements www.chetec.eu

The ChETEC Action (CA16117) is supported by COST (www.cost.eu). COST (European Cooperation in Science and Technology) is a funding agency for research and innovation networks. Our Actions help connect research initiatives across Europe and enable scientists to grow their ideas by sharing them with their peers. This boosts their research, career and innovation.Funded by the Horizon 2020 Framework Programme of the European UnionSee www.chetec.eu for more details