Nuclear Burning in Stars

(Estar)(E) = S(E) e–2E-1

Reaction Rate(star) (E) (E) dE

Gamow Peak

MaxwellBoltzmann

Extrap. Meas.

LUNA resultsMen in pits or wells sometimes

see the stars…. Aristotle

Carlo Broggini, INFN-Pd

INFN - Laboratori Nazionali del Gran Sasso

D.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

luna

Voltage Range :50-400 kV Output Current: 1 mA (@ 400 kV) Absolute Energy error

±300 eVBeam energy spread:

<100 eVLong term stability (1 h) :

5 eVTerminal Voltage ripple:

5 Vpp Ge detector

m-2 h-1

n

cm-2 s-1

p + p d + e+ + e

d + p 3He +

3He +3He +2p 3He +4He 7Be +

7Be+e- 7Li + +e 7Be + p 8B +

7Li + p 8B 2 + e++ e

84.7 % 13.8 %

13.78 % 0.02%

pp chain

14N(p,)15O

Q=7.3 MeV

- 504

-21

278

1414N+pN+p

729772977556

7276

68596793

6176

5241

5183

01515OO

1/2 +

7/2 +

5/2 +

3/2 +

3/2 -

5/2 +

1/2 +

1/2 -

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 C yield in AGB stars

St(0)=1.61±0.08±0.16

keV b

3He(,)7Be

Solar Neutrinos:7Be,8BBBN 7Li

• Cross section from prompt gammaprompt gamma down to 90 keV (CM energy) using 4He beam on 3He target

• Activation via off-line radioactive decayradioactive decay measurements of the 7Be atoms collected in the beam catcher

• All with a final error < 5 %

Q=1.6 MeV

0,3

0,4

0,5

0,6

0,7

0,8

S34 (

0)

[keV

Parker et. al.1963

Robertson et. al.1983

on-line - meas.average

Hilgemeier et. al.1988

Alexander et. al.1984

Osborne et. al.1982

Krwinkel et. al.1982

Nagatani et. al.1969

Volk et. al.1983

activationaverage

Osborne et. al.1982

Hilgemeier et. al.1988

on-line - measurements activation measurements

Nara Singh et. al.2004

Summary of previous measurements

<S34(0)> = 0.51 ± 0.02 keV b <S34(0)> = 0.57 ± 0.03 keV b

0.53 ± 0.05 keV b (9%) [Adelberger 98]0.54 ± 0.09 keV b (16%) [NACRE 99]

Recommended S34(0) values:

R-matrix analysis: 0.51 ± 0.04 keV b (8%) [Descouvemont 2004]

Activation measurement

o 4He beam @ 350 keVo <I> ~ 230 µAo Recirculated 3He @ 0.7

mbar

478

214Bi

214Bi

7Be

Source Determination RelativeUncertainty

Detector efficiency Measured 1.8 %

Beam current Calibrated calorimeter 1.5 %

Beam heating effect Measured (typical correction: 5%)

1.3 %

Target thickness Pressure and temperature measurements

0.6 %

Backscattering loss Measured and simulated (typical correction: 2.1%)

0.5 %

478 keV -ray branching

From literature 0.4 %

Incomplete 7Be collection

Measured and simulated (typical correction: 1.6%)

0.4%

Effective energy Measured 0.5-0.8 %

Parasitic 7Be production

Measured upper limit 0.04 %

Sputtering loss Upper limit from MC Simulation

0.02 %

Total 3.0 %

Systematic uncertainties and corrections

Prompt -spectra

o 4He beam @ 400 keVo <I> ~ 300 µAo Irradiation time: 4.4d

o 4He beam @ 220 keVo <I> ~ 240 µAo Irradiation time:

24.4d

3He(,)7Be:the Sun: 7Be and 8B neutrinos Big-Bang 7Li

14N(p,)15O: down to 70 keV (T=60 T6)

cno from the Sun reduced by 2 Globular cluster age increased by 0.7-1 Gy Higher C yield in AGB stars

LUNA has shown that it is possible to measure

(Estar): 3He (3He,2p)4He, 2H(p,)3He 3He (3He,2p)4He: down to 16 keV

no resonance within the solar Gamow Peak

S 14,1 /5

S 14,1 x5

Standard CF88

25Mg(p,)26Al

Q=6.3 MeV

Nucleosynthesis Mg-Al

Astronomical interest of the from 26Al decay

•Cross section at 180-400 keV (CM energy) using Ge detectorsGe detectors (not underground)

•Cross section at lower energies using BGO BGO summing crystalssumming crystals (underground)