Nuclear astrophysics research in ATOMKI
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Transcript of Nuclear astrophysics research in ATOMKI
Nuclear astrophysics research in ATOMKI
György Gyürky
Institute of Nuclear Research (ATOMKI)
Debrecen, Hungary
NuPECC meeting, October 7-8, 2011, Budapest, Hungary
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Research activities of the nuclear astrophysics group of ATOMKI
Experiments for the astrophyical p-process
Study of the electron screening effect
Half-life measurements relevant to astrophysics
RIB experiments relevant to astrophysics
Application of the Trojan Horse
indirect method
7Be isotope productionfor nuclear astrophysics
experiment
Underground experiments:low cross section measurements
(LUNA collaboration)
etc...
• nucleosynthesis• experiments in ATOMKI
• energy generation• experiments in
international collaboration
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The LUNA collaboration
Italian-German-British-Hungarian collaboration Operates the only underground accelerator of
the world at LNGS, Gran Sasso, Italy Measurement of extremely low cross sections
of astrophysical reactions
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Reactions studied at LUNA
d(p,)3He
3He(,)7Be
7Be(p,)8B
14N(p,)15O
15N(p,)16O
25Mg(p,)26Al
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The importance of 3He(,)7Be
4He
2H
3He
7Li
pp-chain of Hydrogen burning,solar neutrinos
big-bang nucleosynthesis,7Li problem
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Old data of 3He(,)7Be S-factor
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0 500 1000 1500 2000Ec.m. [keV]
S f
acto
r [k
eV b
arn
]
Nagatani 1969Parker 1963Krawinkel 1982Robertson 1983Osborn 1984Osborn act. 1984Hilgemeier 1988Nara Singh 2004on-lineactivation
High uncertainty Ambiguous results
pp-chain big bang
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The LUNA of 3He(,)7Be measurements
Low energies never reached before (Ec.m. = 92 – 170 keV)
With both activation and in-beam methods (good agreement found)
With high precision (<5%)
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The LUNA results
0.200
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0 500 1000 1500 2000
Ec.m. [keV]
S f
acto
r [k
eV b
arn
]
Nagatani 1969Parker 1963Krawinkel 1982Robertson 1983Osborn 1984Osborn act. 1984Hilgemeier 1988Nara Singh 2004LUNA activationLUNA on-line
Big bang 7Li problem not solvedby 3He(,)7Be
Solar 8B neutrino flux uncertaintyreduced from ~8% to ~3%
D. Bemmerer et al., Phys. Rev. Lett. 97 (2006) 122502Gy. Gyürky et al., Phys. Rev. C 75 (2007) 035805F. Confortola et al., Phys. Rev. C 75 (2007) 065803
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ERNA 3He(,)7Be experimentEuropean Recoil Separator for
Nuclear AstrophysicsBochum, Germany (now in Caserta, Italy)
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ERNA Results
A. di Leva et al., Phys. Rev. Lett. 102 (2009) 232502
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3He(,)7Be: outlook
new measurements in ATOMKI high energy activation and indirect
measurements (ANC)
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Experimental study of the astrophysical p-process
n capture
- decay
+ decay
r-pro
cess
p-nucleip-process
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The p-process nucleosynthesis
Secondary process initiated on s- and r-seeds Several sub-processes involved Most important: -process (-induced
reactions) Models are not able
to reproduce the
observed p-isotope
abundances
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Data needs for the p-process
Astrophysics: stellar environment temperature density seed abundances time scale etc...
Nuclear physics masses decay properties reaction rates!!!
Reaction rates:• based on theory• very few experimental data• high uncertainty• experiments highly needed
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Experiments
Alpha-induced reations: 8-15 MeV
Cyclotron
Proton-induced reactions: 1-4 MeV
Van de Graaff
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Capture reaction cross section measurements
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100
1000
10000
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Ec.m./MeV
s/m
b
measured data
statistical model calculation
Comparison with theory
130Ba(,)134Ce
Z. Halász et al., in prep.
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Dependence on input parameters106Cd(,)110Sn
Gy. Gyürky et al., Phys. Rev. C 74 (2006) 025805
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Fine tuning of parameters
G.G. Kiss et al., Phys. Rev. Lett. 101 (2008) 191101
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Alpha-nucleus optical potential
E. Somorjai et al., A&A 333 (1998) 1112.
144Sm(,)148Gd
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Direct determination of alpha-nucleus optical potential High precision elastic scattering experiments Low energies (around Coulomb-barrier) Comparison with global optical potentials Construction of local potentials Experiments:
cyclotron of ATOMKI
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Capture and scattering experiments
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Measured complete angular distributions
G.G. Kiss et al., Phys. Rev. C 83 (2011) 065807
s/s R
uth.
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P-process: Outlook
further needs for experimental data recognized by the scientific community
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For further information...
http://www.atomki.hu/atomki/IonBeam/nag/index_en.html