Carlo Broggini, INFN-Padova

Nuclear Burning in Stars

(Estar)(E) = S(E) e–2E-1

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

MaxwellBoltzmann

Extrap. Meas.

Men in pits or wells sometimes

see the stars…. Aristotle

LUNA beyond the Sun

m-2 h-1 n

cm-2 s-1

luna

LUNA2 (400 kV)

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

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+ + 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

0,45

0,47

0,49

0,51

0,53

0,55

0,57

80 100 120 140 160 180

Ecm [keV]

S(E

) [k

eV b

]

activation-PRL+PRC

activation

on-line

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 -

No direct strength resonance data(level structure derived from the singe particle transfer reaction: 25Mg(3He,d)26Al) 2525Mg+pMg+p

Q = 6306 keVQ = 6306 keV

0 5+

228 0+

2626AlAl00

2626AlAlmm

64965+

190

6436

6399

4-

2- 92

130

Novae explosive Burning (T9>0.1)

AGB or W-R Stars (T9~0.05)

Ex (keV) JECM (keV)6598 5+ 304

25Mg(p,)26Al

Astrophysical sitesAstrophysical sitesAGB stars;AGB stars; Novae; Novae; Massive stars.Massive stars.

Astrophysical sitesAstrophysical sitesAGB stars;AGB stars; Novae; Novae; Massive stars.Massive stars. Nucleosintesis of the elements Nucleosintesis of the elements

24<A<2724<A<27 Astronomical interest of Astronomical interest of 1809 keV1809 keV 26 26Mg Mg lineline

Nucleosintesis of the elements Nucleosintesis of the elements 24<A<2724<A<27 Astronomical interest of Astronomical interest of 1809 keV1809 keV 26 26Mg Mg lineline

MotivationMotivationMotivationMotivation

What else can be done with LUNA II (400kV) ?

proposal submitted to INFN (2008-2012)

reaction Q-value (MeV)

Gamow energy (keV)

Lowest meas. Energy (keV)

LUNA limit

15N(p,)16O 12.13 10-300 130 5017O(p,)18F 5.6 35-260 300 6518O(p,)19F 8.0 50-200 143 8923Na(p,)24Mg

11.7 100-200 240 138

22Ne(p,)23Na 8.8 50-300 250 68

D(,)6Li 1.47 50-300 700(direct)50(indirect)

50

CNO

Ne-Na

BBN

2H(,)6Li

Q=1.47 MeV

Burning energy: 50-300 keV

12C()16O

• We would have the possibility to measure angular distributions down to 600 keV and total S-factor down to 500 keV with 10% accuracy

• Theoreticians ask for 10% uncertainty on Stot(300)

Great step forward: so far,10% accuracy only over 1.5 MeV

•MV-accelerator•12C-enriched targets•Beam intensity: 500A•Detection efficiency: 50% total

2.5% single segment (angular distributions)•Detection set-up: scintillator-crystal ball

Reactions powering the astrophysical s-process

Neutron source reactions: 13C(a,n)16O and 22Ne(a,n)25Mg

- Important for nucleosynthesis of elements heavier than iron

-Take place in helium- and carbon-burning reactions in massive and AGB stars

-For 13C(a,n)16O data above 270 keV are available (Gamow peak ~170 keV, LUNA ~200 keV)

- For 22Ne(a,n)25Mg data above 850 keV are available (Gamow peak ~470-700 keV, LUNA ~630 keV)

MV-accelerator

Accelerator Accelerator requirements:

MV electrostatic acceleratorOption 1: HVEE + conventional RF ion sourceOption 2: NEC + ECR high charge state ion source

Two possible layouts:

letter of intent submitted to LNGS

COLLABORATION

Germany

BOCHUM, Inst. For Experimental Physics, Ruhr-Universitat: C. Rolfs, F. Strieder, H.P. Trautvetter

DRESDEN, Inst. For Radiation Physics, Forschungszentrum Dresden-Rossendorf : D. Bemmerer, M. Marta

Hungary

DEBRECEN, ATOMKI: Z. Elekes, Zs. Fulop, Gy. Gyurky, E. Somorjai

Italy

GENOVA, Università degli Studi and INFN: F. Confortola, P. Corvisiero, H. Costantini, A. Lemut, P. Prati

LNGS, Gran Sasso: A. Formicola, C. Gustavino, M. Junker

MILANO, Università degli Studi, Ist. Di Fisica Generale Applicata and INFN: R. Bonetti, A. Guglielmetti, C. Mazzocchi

NAPOLI, Università, Dip. Scienze Fisiche and INFN: G. Imbriani, A. Di Leva, B. Limata, E. Roca, M. Romano, O. Straniero

NAPOLI, II Università, Dip. Scienze Ambientali and INFN: F. Terrasi

PADOVA, Università degli Studi and INFN: C. Broggini, A. Caciolli, R. Menegazzo, C. Rossi Alvarez

TORINO, Università, Dip. Fisica Sperimentale and INFN: G. Gervino

3He(,)7Be

Solar Neutrinos:7Be,8BBBN 7Li

Q=1.6 MeV

•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 %

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

T½ =52.2±1.5 d

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

ΔΔS = -1.4 S = -1.4 4.2 % 4.2 %

0,45

0,47

0,49

0,51

0,53

0,55

0,57

80 100 120 140 160 180

Ecm [keV]

S(E

) [k

eV b

]

activation-PRL+PRC

activation

on-line

S34(0) = 0.560 S34(0) = 0.560 0.017 keV barn 0.017 keV barn

of 3He(,)7Be down to 93 keV 7Be ≈ prompt

SS3434(0) = 0.560 (0) = 0.560 0.016 keV barn 0.016 keV barn

ΔΦ(B) reduced from 12% to 10%

ΔΦ(Be) reduced from 9.4% to 5.5% (C. Pena Garay)

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

HPGe Efficiency

0.00%

0.05%

0.10%

0.15%

0.20%

0.25%

0.30%

0.35%

0.40%

0.45%

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36

511 keV

662 keV

1173 keV

1275 keV

1332 keV

Effi

cien

za %

0.00%

0.05%

0.10%

0.15%

0.20%

0.25%

0.30%

0.35%

0.40%

0.45%

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36

511 keV

662 keV

1173 keV

1275 keV

1332 keV

7Be counting efficiency 1.8%

Beam intensity 1.5%

Beam heating effect 1.3%

Target density without beam

0.6%

7Be backscattering 0.5%

Incomplete 7Be collection 0.4%

7Be distribution in catcher 0.4%

478 keV branching 0.4%

7Be half-life 0.1%

3He purity in target 0.1%

Beam intensity 1.5%

Target density 1.5%

3He purity 0.1%

Efficiency 1.5%

Angular distribution 1.5%

ACTIVITYACTIVITY PROMPT-PROMPT-

25Mg(p,)26Al

Q=6.3 MeV

Nucleosynthesis Mg-Al

Astronomical interest of the from 26Al decay

•Cross section at 180-400 keV with Ge Ge detectorsdetectors

•Cross section down to 90 keV with BGO BGO summing crystalssumming crystals

Tur

boP

ump

4 BGO Detector

1”x1”NaI(Tl)

Bea

m P

rofil

eM

onito

r

Far

aday

Cup

4 S

lits

Wob

bler

s

Bel

low

Gat

e V

alve

LN2

Tra

p(I

sola

ted)

Lead

shie

ldin

g

Tar

get

incl

LN2

Tra

p an

dH

2O c

oolin

g

* cno from the Sun * Globular cluster age * C yield in AGB stars

15N(p,)16O

Q=12.13 MeV