Hydrogen and Helium burning under Gran Sasso INFN-Padova...

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Hydrogen and Helium burning under Gran Sasso Carlo BrogginiINFN-Padova

Men in pits or wells sometimes see the stars. Aristotle

Stellar Energy+Nucleosynthesis : (Estar) with Estar

Nuclear reactions bw Z1Z2: potential energy due to Coulomb force: Z1Z2e2/R1.44Z1Z2/R MeV (R nuclear radius R1+R2 in fermi)

When the classical turning point is much larger than the nuclear

radius: (E) = S(E) e2 E-1

E is the CM energyS(E) is the astrophysical factor2=31.29Z1Z2(/E)1/2

where is the reduced mass in amu and E is in keV

Narrow resonance at E=ER (virtual state in the compound nucleus):

(E)ab / [(E-ER)2+(/2)2]

with =a+ba (b ) is the partial width for the formation (decay) of the compound state

The charged particle width a is ruled by the transmission probability through the Coulomb barrier (at very low energy much smaller than ))))

Reaction Rate(star) (E) (E) dEGamow Peak


Extrap. Meas.

Background due to cosmic rays:

- Electromagnetic component- Hadrons- Muons: ionization, spallation,

radioactive nuclei, neutrons- Mu-stop: radioactive nuclei- Gamma rays

In 1979 A. Zichichi makes a proposal to the ItalianParliament for building a large underground laboratory inside the highway tunnel underneath the Gran Sasso.

In 1982 the Parliament approves the construction, then completed in 1987.

In 1989 the first underground experiment, MACRO, is starting data taking.

QuickTime and aPhoto - JPEG decompressor

are needed to see this picture.

Surface: 17 800 m2

Volume: 180 000 m3

Ventilation: 1 vol / 3 hours

Muon flux: 3.0 10-8 cm-2s-1

Neutron flux, mainly from (,n) : 2.92 10-6 cm-2s-1 (0-1 keV)0.86 10-6 cm-2s-1 (> 1 keV)

Rn in air: 20-80 Bq m-3

Background due natural radioactivity ( rays):238U (609, 1120, 1764, 2204 keV), Radon (t1/2 3.8 days)232Th (911, 969, 2615 keV)40K (1461 keV from E.C. decay 10.5% B.R.)

Large Cu+Pb shielding possible underground (no muon activation)











ed c








Energy [keV]0 1500500 1000 2000 2500 3000

above groundARC SeibersdorfVKTA RossendorfJRC-IRMMLNGS

BGO spectrum

External Lab, 10 cm Pb


At E3.2 MeV rays are from (n,) reactions

Voltage Range: 50-400 kVOutput Current: 1 mA (@ 400 kV) Absolute Energy error: 300 eVBeam energy spread:


Hydrogen burning in the Sun@15*106 degrees:

6*1011 kg/s of H He+0.7% MH E

activation=prompt gamma

at low energy with 4% error

2H burning in proto-stars @106 degrees

3He (3He,2p)4He

Q = 12.86 MeV

Epmax= 10.7 MeV

Suppression of 7Be and 8B

e due to a resonance?

min=20 fb (2 events/month)No resonance at the Gamow peak

Neutrino oscillations


BBN 7LiSolar Neutrinos:7Be,8B

Q=1.6 MeV

Cross section from prompt gamma down to 90 keV (CM energy) using 4He beam on 3He targetActivation via off-line radioactive decaymeasurements of the 7Be atoms collected in the beam catcherAll with a final error < 5 %

Activation measurement

o 4He beam @ 350 keVo ~ 230 Ao Recirculated 3He @ 0.7 mbar

T =52.21.5 d

Prompt -spectra

o 4He beam @ 400 keVo ~ 300 Ao Irradiation time: 4.4d

o 4He beam @ 220 keVo ~ 240 Ao Irradiation time: 24.4d

down to 93 keV7Be prompt S34(0) = 0.567 0.018 keV b

recommended value 0.56 0.02 (expt) 0.02 (theory)








80 100 120 140 160 180

Ecm [keV]


) [k

eV b





cno S1,14Globular Cluster Age

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

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





Surface colour











The CNO Cycle

- 504











1/2 +

7/2 +

5/2 +

3/2 +

3/2 -

5/2 +

1/2 +

1/2 -

High energy: solid target + HpGe

gamma spectrum of 14N(p,)15O at Ep=140 keV

10-7 mbar 10-6 mbar 10-4 mbar

0.5-2 mbar

Windowless gas-targetMax 10 mbar

Low energy: gas target + BGO

Reaction Rate = 10.95 0.83 counts/dayBackground rate = 21.14 0.75 counts/day

t = 49.12 daysQ = 9277 C

beam energy: 80 keV

*cno from the Sun * Globular Cluster age +1Gy

* more C at the surface of AGB

From a measurement of cno from the Sun

St(0)=1.570.13 keV b

Solar composition problem:Z/X ~0.024 ~ 0.018SSM predictions disagreewith Helioseismology results

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

Metallicity of the Sun core (C+N)Photosphere and core metallicity equal?Correlation with the high C+N of giant planets?

LUNA beyond the Sun: isotope production in the hydrogen burning shell of AGB stars (~30-100 T6), Nova nucleosynthesis (~100-400 T6) and BBN

2H(,)6Li Q=1.47 MeV

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

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

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

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

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

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


17O(p,)14N Q=1.2 MeV

18O(p,)15N Q=4.0 MeV

Uncertainty on 16O, 17O, 18O, 18F and 19F less

than 10% (from 40-50%)

The Ne-Na Cycle

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

Only upper limits (eV) on the strength of the 14 possible resonances below 400 keV (factor 2000 on the rate)

Ne, Na, Mg and Al yield in AGB and Novae (up to a factor 100)

The strength of 5 resonances measured in the first 3 months of the experiment with a neV sensitivity

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

Production of 26Algs in H-burningregions is less efficient than

previously obtained

First measurement of the 92 keV

resonance: =(2.90.6)x 10-10 eV

26Al T = 0.7 My:Nucleosynthesis is still active

Big Bang Nucleosynthesis

Possible nuclear explanation of the 6Li problem?

The 6Li problem: in some very old stars 6Li/7Li measured(from the asymmetry of the 7Li absorption line) ~5*10-2, BBN predicted ~10-56Li source: D(,)6Li, measured only down to 711 keV (BBN production below 400 keV)

D(,)6Li Q=1.47 MeV

~3He(,)7Be set-up(similar Q-value) but

important backgrounddue to (n,n )))) on Ge, Cu,Fe..


A.M. Mukhamedzhanov et al., 2011

F. Hammache et al., 2010

LUNA results, 2014

J. Kiener et al., 2010

P. Mohr et al., 1994

BBN predictions with LUNA results:6Li/7Li =(1.50.3)*10-5, no nuclear solution

R.G.H. Robertson et al., 1981

12C(,)16O the most important reaction ofnuclear astrophysics: production of the elements heavier than A=16, star evolution from He burning to the explosive phase (core collapse and thermonuclear SN) and ratio C/O

Sources of the neutrons responsible for the S-process: 50% of the elements beyond Iron

(,) on 3He, 14N, 15N, 18O

What Next: 3.5 MV accelerator mainly devoted to Helium-Burning (in stars: ~100 T6, ~105 gr/cm3)

LUNA-MV accelerator financed by MIUR, to be installed in Hall C of LNGS (Opera space)

22Ne(,n)25Mg: isotopes with A90 during He and C burning in massive stars

13C(,n)16O: isotopes with A90 during AGB phase of low mass stars


14N(p,)15O: down to 70 keV

cno reduced by 2 with 8% error Sun core metallicityGlobular cluster age increased by 0.7-1 GyMore carbon at the surface of AGB stars

3He (3He,2p)4He: down to 16 keVno resonance within the solar Gamow Peak

, cross section measured with 4% error7Be prompt

25Mg(p,)26Al: first measurement of the 92 keV resonance, strength =(2.90.6)x 10-10 eV

15N(p,)16O: down to 70 keV, reduced by 2

D(,)6Li: no nuclear solution to the 6Li problem

17O(p,)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)

LUNA CollaborationINFN - LNGS (Italia): A. Best, A. Formicola, S. Gazzana, M. Junker, L. Leonzi, A. Razeto

HZDR (Germania): D. Bemmerer, T. Szcs, M. Takcs

INFN Padova (Italia): C. Broggini, A. Caciolli, R. Depalo, R. Menegazzo

INFN Roma La Sapienza (Italia): C. Gustavino

ATOMKI, Debrecen (Ungheria): Z. Elekes, Zs.Flp, Gy. Gyurky, E.Somorjai

Osservatorio di Collurania (Italia): O. Straniero

Ruhr-Universitt Bochum (Germania): F. Strieder

University of Edinburgh (UK): M. Aliotta, T. Davinson, C. Bruno

Universit di Genova (Italia): F. Cavanna, P. Corvisiero, F. Ferraro, P. Prati

Universit e INFN Milano (Italy): A. Guglielmetti, D. Trezzi

Universit e INFN Napoli (Italia): G. Imbriani, A. Di Leva

Universit e INFN Torino (Italia): G.Gervino