First cross-section measurements of the 112Cd(p,γ)113In* reaction at astrophysical energies

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. . First cross section measurements of the 112 Cd(p, γ ) 113 In * reaction at astrophysical energies A. Psaltis, E.-M. Assimakopoulou, E. Malami, I. Psyrra, V. Lagaki, A. Kanellakopoulos, T.J Mertzimekis 1 , V. Foteinou, M. Axiotis, A. Lagoyannis and S. Harissopulos 2 1 Faculty of Physics, University of Athens, 2 INPP, NSCR "Demokritos" 23rd Symposium of the Hellenic Nuclear Physics Society Thessaloniki, June 21st, 2014 1 / 25

Transcript of First cross-section measurements of the 112Cd(p,γ)113In* reaction at astrophysical energies

Page 1: First cross-section measurements of the 112Cd(p,γ)113In* reaction at astrophysical energies

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First cross section measurements of the112Cd(p, γ)113In∗ reaction at astrophysical energies

A. Psaltis, E.-M. Assimakopoulou, E. Malami, I. Psyrra, V. Lagaki, A. Kanellakopoulos, T.J Mertzimekis1, V. Foteinou, M. Axiotis, A. Lagoyannis and S. Harissopulos2

1Faculty of Physics, University of Athens, 2INPP, NSCR "Demokritos"

23rd Symposium of the Hellenic Nuclear Physics SocietyThessaloniki, June 21st, 2014

1 / 25

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Outline

1. Introduction & Motivation

2. Theoretical Background

3. Experiments 4. Results & Discussion

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Outline

1. Introduction & Motivation 2. Theoretical Background

3. Experiments 4. Results & Discussion

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Outline

1. Introduction & Motivation 2. Theoretical Background

3. Experiments

4. Results & Discussion

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Outline

1. Introduction & Motivation 2. Theoretical Background

3. Experiments 4. Results & Discussion

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Introduction: How elements are formed?

Everything is made of atoms.

Our quest to explain the origin of the elements startedin 1957 by Burbidge, Burbidge, Hoyle and Fowler (B2HF ).

They proposed that the elements are producedin the hearts of stars via nuclear reactions and explained theabundance pattern we observe in the solar system.

[E. M. Burbidge, G. R. Burbidge, William A. Fowler, and F. Hoyle, Rev. Mod. Phys. 29, 547 1957,doi:10.1103/RevModPhys.29.547]

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Introduction: How elements are formed?

Everything is made of atoms.

Our quest to explain the origin of the elements startedin 1957 by Burbidge, Burbidge, Hoyle and Fowler (B2HF ).

They proposed that the elements are producedin the hearts of stars via nuclear reactions and explained theabundance pattern we observe in the solar system.

[E. M. Burbidge, G. R. Burbidge, William A. Fowler, and F. Hoyle, Rev. Mod. Phys. 29, 547 1957,doi:10.1103/RevModPhys.29.547]

University of AthensCross section measurements of the 112Cd(p,γ)113In∗ reaction at astrophysical energies 3 / 25

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Introduction: How elements are formed?

Everything is made of atoms.

Our quest to explain the origin of the elements startedin 1957 by Burbidge, Burbidge, Hoyle and Fowler (B2HF ).

They proposed that the elements are producedin the hearts of stars via nuclear reactions and explained theabundance pattern we observe in the solar system.

[E. M. Burbidge, G. R. Burbidge, William A. Fowler, and F. Hoyle, Rev. Mod. Phys. 29, 547 1957,doi:10.1103/RevModPhys.29.547]

University of AthensCross section measurements of the 112Cd(p,γ)113In∗ reaction at astrophysical energies 3 / 25

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Introduction: How elements are formed?The nuclear burning stops at Iron (Fe) and the star is collapsed by gravity.

Elements above iron peak are created via explosive nucleosynthetic processes(s-process, r-process).

[K. Langanke and F.-K. Thielemann, Europhysics News Vol. 44, No. 3, 2013, pp. 23-26, doi:10.1051/epn/2013304]

University of AthensCross section measurements of the 112Cd(p,γ)113In∗ reaction at astrophysical energies 4 / 25

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Introduction: How elements are formed?The nuclear burning stops at Iron (Fe) and the star is collapsed by gravity.

Elements above iron peak are created via explosive nucleosynthetic processes(s-process, r-process).

[K. Langanke and F.-K. Thielemann, Europhysics News Vol. 44, No. 3, 2013, pp. 23-26, doi:10.1051/epn/2013304]

University of AthensCross section measurements of the 112Cd(p,γ)113In∗ reaction at astrophysical energies 4 / 25

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Introduction: How elements are formed?The nuclear burning stops at Iron (Fe) and the star is collapsed by gravity.

Elements above iron peak are created via explosive nucleosynthetic processes(s-process, r-process).

[K. Langanke and F.-K. Thielemann, Europhysics News Vol. 44, No. 3, 2013, pp. 23-26, doi:10.1051/epn/2013304]

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..

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Introduction: p-process & p-nuclei

There are about 30 relatively neutron deficient nuclides with massnumbers of A≥74 (between 74Se and 196Hg) that cannot besynthesized by any of the known neutron capture processes.

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..

Motivation: Why a (p,γ) reaction?

There are > 20.000 reactions in the region of the p-process.

This huge reaction network is computed theoretically using theHauser Feshbach (H-F) model of nuclear reactions.

Experimental cross sections of (n, γ), (p, γ) and (α, γ) reactions areused for adjusting Hauser-Feshbach model parameters and thereforeimprove theoretical predictions.

[J. José and C. Iliadis, Rep. Prog. Phys. 2011 74 096901, doi: 10.1088/0034-4885/74/9/096901]

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Motivation: Why 113In?113In is a p-nucleus and is underproducted in γ-process.

[W. Rapp et al. 2006 ApJ 653 474 doi:10.1086/508402]

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Motivation: Why 113In?113In is a p-nucleus and is underproducted in γ-process.

[W. Rapp et al. 2006 ApJ 653 474 doi:10.1086/508402]

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Our Work

[T. Rauscher et al 2013 Rep. Prog. Phys. 76 066201 doi:10.1088/0034-4885/76/6/066201] Review Paper

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Our Work

[T. Rauscher et al 2013 Rep. Prog. Phys. 76 066201 doi:10.1088/0034-4885/76/6/066201] Review Paper

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Experimental Setup: Supernova in the lab

• Tandem Van de Graaff5.5 MV accelerator ofN.C.S.R "Demokritos"

• Current:200− 500 nA

• Energy Range:2.8− 3.4MeV

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Experimental Setup: Supernova in the lab

• Electronically controlled turntable• 4 HPGe detectors (100%)• 8 different detector angles(angular distributions)

• in-beam and activation technique

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Target

4-layer target:

• 112Cd (99.7% enriched) - 1.2mg/cm2

• nat83Bi - 40 mg/cm2

• nat49In - 1 mg/cm2

• nat29Cu - 18mg/cm2

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Typical spectrum of the 112Cd(p, γ)113In reaction

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Typical spectrum of the 112Cd(p, γ)113In reaction

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Typical spectrum of the 112Cd(p, γ)113In reaction

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Angular Distributions

Standard angular distribution for an E2 transition:W (θ) = A0 (1 + a2P2(cosθ) + a4P4(cosθ))

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Angular Distributions

Standard angular distribution for an E2 transition:W (θ) = A0 (1 + a2P2(cosθ) + a4P4(cosθ))

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Angular Distributions

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Theoretical predictions: TALYS v1.6

Potential Nuclear LevelDensity

γ StrengthFunction

TALYS-1 Koning Delaroche Constant Temperature

Fermi Gas

Kopecky-Uhl

TALYS-2 Baude-Delaroche-

Girod

Goriely-Demetriou Hartree-Fock-BCS

TALYS-3 Baude-Delaroche-

Girod

Hilaire-Goriely Hartree-Fock-

Bogolyubov

Table: TALYS v1.6 combinations

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Theoretical predictions: TALYS v1.6

Potential Nuclear LevelDensity

γ StrengthFunction

TALYS-1 Koning Delaroche Constant Temperature

Fermi Gas

Kopecky-Uhl

TALYS-2 Baude-Delaroche-

Girod

Goriely-Demetriou Hartree-Fock-BCS

TALYS-3 Baude-Delaroche-

Girod

Hilaire-Goriely Hartree-Fock-

Bogolyubov

Table: TALYS v1.6 combinations

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Theoretical predictions: TALYS v1.6

Potential Nuclear LevelDensity

γ StrengthFunction

TALYS-1 Koning Delaroche Constant Temperature

Fermi Gas

Kopecky-Uhl

TALYS-2 Baude-Delaroche-

Girod

Goriely-Demetriou Hartree-Fock-BCS

TALYS-3 Baude-Delaroche-

Girod

Hilaire-Goriely Hartree-Fock-

Bogolyubov

Table: TALYS v1.6 combinations

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Partial Cross Sections

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Partial Cross Sections

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Partial Cross Sections

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Total Cross Section

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Conclusions

• For the first time cross sections and angular distributions of 113Inat astrophysical energies were measured experimentally.

• Experimental data of cross sections are in goodagreement with Hauser-Feshbach predictions.

• TALYS-2 combination seems to fit better our data.• The origin of 113In and whether it is a p-nuleus are still unclear.

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Conclusions

• For the first time cross sections and angular distributions of 113Inat astrophysical energies were measured experimentally.

• Experimental data of cross sections are in goodagreement with Hauser-Feshbach predictions.

• TALYS-2 combination seems to fit better our data.• The origin of 113In and whether it is a p-nuleus are still unclear.

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Conclusions

• For the first time cross sections and angular distributions of 113Inat astrophysical energies were measured experimentally.

• Experimental data of cross sections are in goodagreement with Hauser-Feshbach predictions.

• TALYS-2 combination seems to fit better our data.

• The origin of 113In and whether it is a p-nuleus are still unclear.

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Conclusions

• For the first time cross sections and angular distributions of 113Inat astrophysical energies were measured experimentally.

• Experimental data of cross sections are in goodagreement with Hauser-Feshbach predictions.

• TALYS-2 combination seems to fit better our data.• The origin of 113In and whether it is a p-nuleus are still unclear.

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.. C'est fini!

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Extra Slides

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Ratio of σground and σtotal

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Ratio of σmeta and σtotal

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