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Carlo Broggini INFN-Padova. LUNA, the Sun and the other stars. Stellar Energy+Nucleosynthesis. Hydrogen Burning. s (E star ) with E star << E Coulomb. s ( E ) = S(E) e –2 ph E -1. 2 ph = 31.29 Z 1 Z 2 m/E. m = m 1 m 2 / ( m 1 + m 2 ). . Reaction Rate(star) . F (E) s (E) dE. s.

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slide1

Carlo Broggini

INFN-Padova

LUNA, the Sun and the other stars

  • Stellar Energy+Nucleosynthesis
  • Hydrogen Burning
  • s(Estar) with Estar << ECoulomb

s(E) = S(E) e–2phE-1

2ph = 31.29 Z1Z2m/E

m = m1m2 / (m1+m2)

Reaction Rate(star)

F(E) s(E) dE

s

Meas.

Extrap.

Gamow Peak

S(E)

Maxwell

Boltzmann

s

slide2

Laboratory for Underground

Nuclear Astrophysics

Beam: H,He

Voltage Range :50-400 kV

Output Current: ~1 mA

Absolute Energy error

±300 eV

Beam energy spread:

<100 eV

Long term stability (1 h) :

5 eV

Terminal Voltage ripple:

5 Vpp Ge detector

slide3

Hydrogen burning in the Sun

@15*106 degrees:

6*1011 kg/s of H He

+0.7% MH E

H+2H burning in proto-stars

@106 degrees

Resonance?

activation=prompt gamma

s at low energy with 4% error

slide4

3He (3He,2p)4He

Q = 12.86 MeV

Epmax= 10.7 MeV

Suppression of 7Be and 8B e due to a resonance?

smin=20 fb (2 events/month)

No resonance at the Gamow peak

Neutrino oscillations

slide5

14N(p,g)15O

Q=7.3 MeV

£

turnoff

F

S1,14

cno

Blue

Red

  • Globular Cluster Age

Surface colour

AgeCluster=F(£turnoff)

S(0)=3.5-1.6+0.4 keV b (Ad98)

S(0)=3.2-0.8+0.8 keV b (An99)

£to=F(S1,14)

slide6

278

“High” energy: solid target + HpGe

7556

1/2+

7297

14N(p,g)15O

7276

7/2 +

gamma spectrum of 14N(p,g)15O at

140 keV beam energy

14N+p

6859

5/2 +

-21

6793

3/2 +

- 504

6176

3/2 -

5241

5/2 +

5183

1/2 +

Low energy: gas target + BGO

15O

0

1/2 -

beam energy 90 keV

slide7

St(0)=1.57±0.13 keV b

*½cno from the Sun

* Globular Cluster age +1Gy

* more C at the surface of AGB

Solar composition problem:

Z/X ~0.024 ~ 0.018

SSM predictions disagree

with Helioseismology results

cno=f(Z,S14), ~30% decrease from high to low metallicity

From a measurement of cno from the Sun

Metallicity of the Sun core (C+N)

Photosphere and core metallicity equal?

slide8

LUNA beyond the Sun:isotope production in the hydrogen burning shell of

AGB stars (~30-100 T6), Nova nucleosynthesis (~100-500 T6) and BBN

15N(p,g)16O Q=12.13 MeV

25Mg(p,g)26Al Q=6.3 MeV

17O(p,g)18F Q=5.6 MeV

2H(α,g)6LiQ=1.47 MeV

17O(p,α)14N Q=1.2 MeV

22Ne(p,g)23Na Q=8.8 MeV

18O(p,g)19F Q=8.0 MeV

18O(p,α)15N Q=4.0 MeV

23Na(p,g)24Mg Q=11.7 MeV

............

slide9

LUNA beyond the Hydrogen burning: 3.5 MV accelerator

mainly devoted to Helium-Burning (in stars: ~100 T6, ~105 gr/cm3)

12C(a,g)16Othe most important reaction of nuclear astrophysics: production of the elements heavier than A=16, star evolution from He burning to the explosive phase and ratio C/O

13C(a,n)16O, 22Ne(a,n)25Mgthe

stellar sources of the neutrons

responsible for the S-process

(a,g) on14N, 15N, 18O……

June 2012: accelerator+site preparation financed by the Italian Ministry of University and Research with 2.8 ME

‘Starting the LUNA-MV

Collaboration’, LNGS,

February 6th-8th 2013

slide10

3He (3He,2p)4He: sdown to 16keV

  • no resonance within the solar Gamow Peak
  • 3He(,g)7Be:

7Be ≈promptg

Cross section measured with 4% error

  • 14N(p,g)15O: sdown to70keV
  • cnoreduced 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
  • 15N(p,g)16O: sdown to70 keV, reduced by  2
  • 25Mg(p,g)26Al: first measurement of the 92 keV resonance,
  • strength ωγ=(2.9±0.6)x 10-10 eV
  • 17O(p,g)18F: rate uncertainty @ Novae temperature reduced to 5%
  • uncertainty on 18O, 18F and 19F less than 10% (from 40-50%)
  • Future:Hydrogen and Helium burning (3.5 MV accelerator)
slide12

3He(,g)7Be

Q=1.6 MeV

  • Solar Neutrinos: 7Be,8B
  • F  S34
  • BBN 7Li
slide13

s down to 93 keV

  • 7Be ≈ prompt g
  • S34(0) = 0.567  0.018 keV barn