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Published byCamilla Stevens Modified over 9 years ago
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( E ) = S(E) e –2 E -1 2 m m m m Reaction Rate(star) (E) (E) dE Gamow Peak Maxwell Boltzmann Extrap. Meas. Carlo Broggini, INFN-Padova Stellar Energy+Nucleosynthesis (E star ) with E star << E Coulomb Hydrogen Burning LUNA, the Sun and the other stars S(E)
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Laboratory for Underground Nuclear Astrophysics Voltage Range :50-400 kV Output Current: 1 mA (@ 400 kV) Absolute Energy error ±300 eV Beam energy spread: <100 eV Long term stability (1 h) : 5 eV Terminal Voltage ripple: 5 Vpp Ge detector
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p + p d + e + + e d + p 3 He + 3 He + 3 He +2p 3 He + 4 He 7 Be + 7 Be+e - 7 Li + + e 7 Be + p 8 B + 7 Li + p 8 B 2 + e + + e pp chain 6% prediction of 7 Be solar neutrino flux, opacity dominant error source Proto-stars and BBN In search of the resonance 85%
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3 He ( 3 He,2p) 4 He Q = 12.86 MeV min = 0.02 pb E p max = 10.7 MeV Suppression of 7 Be and 8 B ?
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14 N(p, g ) 15 O Q=7.3 MeV cno F S 1,14 Globular Cluster Age S(0)=3.5 -1.6 +0.4 keV b (Ad98) S(0)=3.2 -0.8 +0.8 keV b (An99) E<1.20 MeV E<1.73 MeV
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- 504 -21 278 14 N+p 7297 7556 7276 6859 6793 6176 5241 5183 0 15 O 1/2 + 7/2 + 5/2 + 3/2 + 3/2 - 5/2 + 1/2 + 1/2 - “High” energy: solid target + HpGe gamma spectrum of 14 N(p, ) 15 O at 140 keV beam energy 14 N(p, g ) 15 O Low energy: gas target + BGO beam energy 90 keV
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* ½ cno from the Sun * Globular Cluster age +1Gy * more C at the surface of AGB From a measurement of cno from the Sun S t (0)=1.61±0.18 keV b New study with a ‘clover’ detector of the capture to the ground state S t (0)=1.57±0.13 keV b Metallicity of the Sun core (C+N) Photosphere and core metallicity equal? 2005: solar composition problem
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2 H(α, g ) 6 Li Q=1.47 MeV 15 N(p, g ) 16 O Q=12.13 MeV 17 O(p, g ) 18 F Q=5.6 MeV 23 Na(p, g ) 24 Mg Q=11.7 MeV 22 Ne(p, g ) 23 Na Q=8.8 MeV 18 O(p, g ) 19 F Q=8.0 MeV 25 Mg(p, g ) 26 Al Q=6.3 MeV LUNA beyond the Sun: isotope production in the hydrogen burning shell of AGB stars (~30-100 T 6 ), Nova nucleosynthesis (~100-500 T 6 ) and BBN............ down to 70 keV reduced by factor 2 down to 92 keV resonance: the lowest ever directly measured resonance strength
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12 C( , g ) 16 O the ‘Holy Grail’ of nuclear astrophysics 13 C( ,n) 16 O, 22 Ne( ,n) 25 Mg the stellar sources of the neutrons responsible for the S-process ( , g ) on 14 N, 15 N, 18 O…… LUNA beyond the Hydrogen burning: 3.5 MV accelerator @Gran Sasso - Letter of Intent to LNGS 2007 - Round Table @LNGS 2/2011 http://luna.lngs.infn.it/ Proposal
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3 He( , g ) 7 Be: 14 N(p, g ) 15 O: down to 70 keV cno reduced by 2 with 8% error Sun core metallicity Globular cluster age increased by 0.7-1 Gy More carbon at the surface of AGB stars 3 He ( 3 He,2p) 4 He: down to 16 keV no resonance within the solar Gamow Peak Δ Φ( Be ) reduced to 6% 7 Be ≈ prompt g 15 N(p, g ) 16 O: down to 70 keV, reduced by 2 25 Mg(p, g ) 26 Al: first measurement of the 92 keV resonance Future: Hydrogen burning in shell, Helium burning
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INFN - Laboratori Nazionali del Gran Sasso D.Bemmerer,C.Broggini,A.Caciolli,P. Corvisiero,H.Costantini, Z.Elekes, A.Formicola, Z. Fülöp, G.Gervino,A.Guglielmetti, C.Gustavino, G. Gyurky, G. Imbriani, M.Junker, A.Lemut, M.Marta,C.Mazzocchi,R.Menegazzo, P.Prati, V.Roca, C.Rolfs, C.RossiAlvarez,E.Somorjai, O.Straniero,F.Strieder, F.Terrasi,H.P.Trautvetter INFN : Genova, LNGS, Milano, Napoli, Padova, Torino Inst.Physik mit Ionenstrahlen, Ruhr- Universität Bochum Forschungszentrum Dresden-Rossendorf Atomki Debrecen LUNA
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3 He( , g ) 7 Be Solar Neutrinos: 7 Be, 8 B F S 34 BBN 7 Li Q=1.6 MeV
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down to 93 keV 7 Be ≈ prompt g S 34 (0) = 0.567 0.018 keV barn Δ Φ( B ) reduced to 11% Δ Φ( Be ) reduced to 6% ( dominant error source: opacity ) Borexino
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