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Nuclear Burning in Starsσ(Estar) σ(E) = S(E) e–2πη E-1
Reaction Rate(star) ÷∫Φ(E) σ(E) dE
Gamow Peak
MaxwellBoltzmann
Extrap. Meas.
σ
Underground Nuclear Astrophysics and Solar NeutrinosMen in pits or wells sometimes
see the stars…. Aristotle
Carlo Broggini, INFN-Pd
INFN - Laboratori Nazionalidel Gran SassoD.Bemmerer,R.Bonetti,C.Broggini*,F.Confortola,P.Corvisiero,H.Costantini,Z.Elekes, A.Formicola, Z. Fülöp, G.Gervino,A.Guglielmetti, C.Gustavino, G. Gyurky, G. Imbriani, M.Junker, A.Lemut, B.Limata, V.Lozza,M.Marta,R.Menegazzo, P.Prati, V.Roca, C.Rolfs, M.Romano, C.RossiAlvarez, O.Straniero,F.Strieder, E.Somorjai,F.Terrasi,H.P.Trautvetter
•INFN :
Genova, LNGS, Milano, Napoli, Padova, Torino
•Inst.Physik mit Ionenstrahlen, Ruhr-Universität Bochum (GE)
•Atomki Debrecen (Hungary)
LUNALUNA
Φµ= 0.7 m-2 h-1 Φn ≈ 3∗10−6 cm-2 s-1
luna
LUNA2 (400 kV)
Voltage Range :50-400 kVOutput 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
LUNA1 ( 50 kV)
Voltage Range :1 - 50 kV
Output Current:1 mA
Beam energy spread:20 eV
Long term stability (8 h):10-4
Terminal Voltage ripple:5 10-5
p + p → d + e+ + νe
d + p → 3He + γ
3He +3He → α + 2p 3He +4He → 7Be + γ
7Be+e-→ 7Li + γ +νe7Be + p → 8B + γ
7Li + p → α + α 8B→ 2α + e++ νe
84.7 % 13.8 %
13.78 % 0.02 %
pp chain
3He (3He,2p)4He
Q = 12.86 MeV
σmin = 0.02 pb
Epmax= 10.7 MeV
ν from the Sun
14N(p,γ)15OQ=7.3 MeV
νcno Φcno∼ S1,14
Globular Cluster Age
gamma spectrum of 14N(p,γ)15O at Ep=140 keV
“High” energy: solid target + HpGe
10-7 mbar 10-6 mbar 10-4 mbar
0.5-2 mbar
Windowless gas-targetMax 10 mbar
Low energy: gas target + BGO
beam energy: 90 keV
3He(α,γ)7BeQ=1.6 MeV
Solar Neutrinos Sun core properties(largest nuclear physics uncertainty in the SSM)
Big-Bang 7Li
• Cross section of direct decaydirect decay down to 60-70 keV (CM energy) using 4He beam on 3He target
• Reaction Yield around 100-150 keV (CM energy) via off-line radioactive decayradioactive decay measurements of the recoils collected in the beam catcher
• All with a final error < 5 %
HPGe
Lead shield
1st2nd3rd
Expected attenuation for1.6 MeV γs: 10-5-10-6
(GEANT4 simulations)
Movable silicon detector for I*ρ measurement
Removable calorimeter cap for off-line 7Be-activity measurement
33He gasHe gas
3He(α,γ)7Be the Sun, big-bang 7Li
14N(p,γ)15O: σ down to 70 keV (T=60 T6)
νcno from the Sun reduced by ∼ 2Globular cluster age increased by 0.7-1 GyHigher C yield in AGB stars
LUNA has shown that it is possible to measureσ(Estar): 3He (3He,2p)4He, 2H(p,γ)3He
3He (3He,2p)4He: σ down to 16.5 keVno resonance within the solar Gamow Peak
D abundance
Proto-stars
Big-bang
D(p,γ)3HeQ = 5.5. MeV
S 14,1 /5
S 14,1 x5
Standard CF88
25Mg(p,γ)26AlQ=6.3 MeV
Nucleosynthesis Mg-Al
Astronomical interest of the γ from 26Al decay
•Cross section at 180-400 keV (CM energy) using GeGedetectorsdetectors (not underground)
•Cross section at lower energies using BGO summing BGO summing crystalscrystals (underground)