Gianluca ImbrianiPhysics Department of University of Naples Federico II, Italian National Institute of Nuclear Physics (INFN) and Joint Institute of Nuclear Astrophysics (JINA)

gianluca.imbriani@na.infn.it

Reaction rates for nucleosynthesys of ligh and intermediate-mass isotopes:

14N(p,)15O, 15N(p,)16O, 25Mg(p,)26Mg,

17O(p,)18F

LUNA I50 kV

LUNA II 400 kV

LNGS Lab

Voltage Range :1 - 50 kV

Output Current:1 mA

Beam energy spread:20 eV

LUNA 1997-2012 - experimental set-ups

Voltage Range :50 - 400 kV

Output Current:500 mA

Beam energy spread:70 eV

CRO

SS S

ECTI

ON

LOGSCALE

direct measurements

EG

Interaction energy E

(E)

non-resonant

resonance

extrapolation needed !

man

y or

ders

of

mag

nitu

de

Er

non resonant process

interaction energy E

extrapolation direct measurement

0

S(E)

LINEARSCALE

S(E)

-FAC

TOR

-Er

sub-

thre

shol

d re

sona

nce

low-energy tailof broad

resonance

EG Most of the reactions of astrophysical interest happen via radiative capture.3He(a,g)7Be, 14N(p,g)15O , 12C(a,g)16C...

Problem of extrapolation

p+p[keV]

3He+3He[keV]

3He+4He[keV]

7Be+p[keV]

14N+p[keV]

6 22 23 18 27

40K

214Bi 232Th

40K 214Bi 232Th E>4MeV

0.45 0.04 0.10 0.38

0.09 0.04 0.04 0.0008

Gran Sasso shielding: 3800 m w.e.

Radiation LNGS/out

muonsneutrons

10-6

10-3

Why going underground 1st

environmental radioactivity cosmic rays

Therefore, the advantage of an underground environment is evident for high Q-value reactions such as 14N(p,)15O, 15N(p,)16O, 17O(p,)18F, 25Mg(p,)26Al......

Why going underground 2nd

HpGe spectrum Ecm= 230keV«light» Pb shielding

14N(p,g)15O - EPJA 25(2005)

11B(p,g)12C

Beam induced background

• Solar neutrinos: 3He(3He, 2p)4He, 3He(a,g)7Be ,14N(p,g)15O

• Big Bang nucleosynthesis:

2H(p,g) 3He, 3He(a,g)7Be, 4He(d,g)6Li

• Age of Globular Clusters and C production in AGB:

14N(p,g)15O

• Light nuclei nucleosynthesis - 17O/18O abundaces, F origin, 26Al g-ray in the Galaxy, 26Mg excess....:

15N(p,g)16O, 17O(p,g)18F(b+)18O, 25Mg(p,g)26Al(b+)26Mg

LUNA program: astrophysical motivation

1E-02

1E+02

1E+06

1E+10

0 1E+07 2E+07 3E+07 4E+07 5E+07

T[K]

/X

2

pp-chain

CNO

Turn Off luminosity

CNO cycle

pp chain

the o

nse

t of

the C

NO

12C

13N

(p,

)g

6×10

9 y

14N(p, )g

1×109 y

15O

(p,

)g

2×10

12y

13C

e+n

10 m

15N

e+n

2 m

CN17F

(p,

)g

17O

e+n

64 s

NO

16O(p, )a

1×108 y

(p, )g

(p, )a18F(p, )g

18O

e+n

108 m

(p, )a

CNQeff = 26.02 MeV

NOQeff = 25.73 MeV

14N(p,g)15O is the bottleneck of the cycle, therefore the initial abundance of C, N, O is, mostly, converted in 14N!!

14N(p,g)15O: Age of Globular Clusters

12C

13N

(p,

)g

6×10

9 y

14N(p, )g

1×109 y

15O

(p,

)g

2×10

12y

13C

e+n

10 m

15N

e+n

2 m

CN17F

(p,

)g

17O

e+n

64 s

NO

16O(p, )a

1×108 y

(p, )g

(p, )a18F(p, )g

18O

e+n

108 m

(p, )a

CNQeff = 26.02 MeV

NOQeff = 25.73 MeV

14N(p,g)15O is the bottleneck of the cycle, therefore the initial abundance of C, N, O is, mostly, converted in 14N!!

Problem between observation and stellar models: observed over-production of all chemical elements above C by a factor of 2.

The smaller the 14N(p,γ )15O rate, the larger is the amount of 12C and metals, which will pollute the interstellar medium.

14N(p,g)15O: Yield production of 12C in AGB

1.E-02

1.E-01

1.E+00

1.E+01

1.E+02

1.E+03

0 50 100 150 200 250 300 350 400 450

E [keV]

S-f

ac

tor

[ke

V b

]

Stot (keV b)

gas target

gs

6.79

6.17

5.24

5.18

14N(p,g)15O: LUNA resultsEx (keV)

6791

6172

5180

0

ECM (keV)

Q = 7297

14N + p

15O

7540

HpGe spectrum Ecm=110keV BGO spectrum Ecm=70keV

PhLB 591(2004), EPJA 25(2005), PRC 78 (2008) NuPhyA 779(2006), PhLB, 634(2006)

14N(p,g)15O: S(0) and reaction rateDIRECT MEASUREMENTS INDIRECT MEASUREMENTS Review

EX [keV]

Schröeder et al.NuPhA 467(1987)

LUNA EPJ 25(2005)

LENA PRL 94(2005)

Mukhamedzhanov et al.PRC 67(2005)

Nelson et al.PRC 68(2003) Solar Fusion II

0 1.55 ± 0.34 0.25 ± 0.06 0.15 ± 0.07 0.15 ± 0.07 0.27 ± 0.055183 0.010 ± 0.003 0.010 ± 0.0035241 0.070 ± 0.003 0.070 ± 0.0036173 0.14 ± 0.05 0.08 ± 0.03 0.13 ± 0.02 0.15 ± 0.07 0.15 ± 0.07 0.13 ± 0.06 6793 1.41 ± 0.02 1.20 ± 0.05 1.4 ± 0.2 1.40 ± 0.20 1.18 ± 0.05tot (3.20 ± 0.54) (1.61 ± 0.08) (1.68 ± 0.09) (1.70 ± 0.22) (1.66 ± 0.08)

LUN

A/N

ACRE

Stellar calculation done with the FRANEC code

The age of the oldest Globular Clusters should be increased by about 0.7-1 Gyr. The lower limit to the Age of the Universe is 14 ± 1 Gyr.In good agreement with the precise detrmination of WMAP.

G. Imbriani, et al., A&A 420(2004)

With 14N(p,γ)15O rate = ½ of NACRE better agreement between observation and calculation.

14N(p,g)15O: astrophysical consequences

Ground state transition

6.79MeV state transition6.17MeV state transition

Data from Schroeder, LENA and LUNA

Adopted hereS(0) = 1.66 ± 0.12 8% uncertainty

Extrapolation toward lower energy

• Solar neutrinos: 3He(3He, 2p)4He, 3He(a,g)7Be 14N(p,g)15O

• Big Bang nucleosynthesis: 2H(p,g) 3He, 3He(a,g)7Be, 4He(d,g)6Li

• Age of Globular Clusters and C production in AGB :14N(p,g)15O

• Light nuclei nucleosynthesis - 17O/18O abundaces, F origin, 26Al g-ray in the Galaxy, 26Mg excess....:

15N(p,g)16O, 17O(p,g)18F(b+)18O, 25Mg(p,g)26Al(b+)26Mg,

H-shell burning @LUNA

12C

13N

(p,

)g

6×10

9 y

14N(p, )g

1×109 y

15O

(p,

)g

2×10

12y

13C

e+n

10 m

15N

e+n

2 m

CN17F

(p,

)g

17O

e+n

64 s

NO

16O(p, )a

1×108 y

(p, )g

(p, )a18F(p, )g

18O

e+n

108 m

(p, )a

Q=12127 keV15N(p,g0)16O

15N(p,ag4.4MeV)12C

15N(p,)/(p,) ~ 1000

Ex (keV) Jp

12465

7117

0

1-

1-

0+

15N+p

16O level scheme

Q = 12127 keV

0+

13155 1-

6049

15N(p,a)/(p,g): first branch of the CNO cycle

We measured the cross section in a wide energy window:1. 2.5 MeV > E > 0.8 MeV KN 3.5 MV @ Notre Dame + HpGe clover detector;2. 0.8 MeV > E > 0.3 MeV JN 1 MV @ Notre Dame + HpGe clover detector;3. 0.4 MeV > E > 0.12 MeV 400 KV @ LUNA + HpGe detector.

We used TiN deposited 50 and 150 nm targets Ta backing placed @ 45°, produced in Karlsruhe.

1

2

3

15N(p,g)16O LUNA & ND experimental set up

15N(p,g)16O LUNA & ND reults

The leakage from CN to NO reduces of a factor 2:every about 2000 cycles of the main CN cycle, one goes to NO cycle. Before every 1000 cycles was the value recommended by the NACRE compilations (Angulo et al., 1999)

KN ND JN NDLUNADIRECT MEASUREMENTS INDIRECT

MEASUREMENTSHebbard’60

NuPhy 15(1960)

Rolfs’74 NuPhy A 235(1974)

LUNA-NDPRC 82(2010)

Mukhamedzhanov et al.PRC 78(2008)

S(0) keVb 32 ± 6 64 ± 6 39.6 ± 2.6 36 ± 6

P.J. Le Blanc, et al., PRC 82 (2010)

Ex (keV) Jp

6343

6280

0

4-

3+

5+

25Mg+p

26Al level scheme

Q = 6306 keV

228 0+

26Al0

26Alm

1809

Ex (keV)

26Mg 0

2+

0+g- ray 1.8 MeV

+b

Signature of 26Mg production during the Hydrogen burning (RGB, AGB)

26Mg excess in meteorites

Evidence that 26Al nucleosynthesis is still active (WR stars, SN and NOVAE)

T ½ = 7.2 105 y << galactic time scale

24Mg

(p,

27Al(p,

27Si

(p,

e+ 4 s

26Al

26Mg

(p,e

+

6 s

25Mg

25Al(p

,e

+7 s

(p, (p,

25Mg(p,g)26Al – Astrophysical motivations

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

-26

Q6306

0 5+

228 0+

26Al0 (t1/2 = 7·105y)

26Alm (t1/2 = 6s)

6496 5+(4+) 190

6436

6414

6399

6364

6343

6280

4-

0+

2-

3+

4-

3+

37

58

93

108

130

26Al

Novae explosive

Burning (T

9 >0.1)

AG

B or W

-R

Stars (T

9 ~0.05)

Ex (keV)

J

ECM (keV)

1809

0

417 3+

6610 3- 304

26Mg

25Mg+p

isomericstate

• High efficiency (about 50%) – Low resolution set-up -ray Spectroscopy with 4pBGO + solid target

-ray Spectroscopy with HPGe High resolution - Low efficiency (<1% @ high energy) + solid target @55°

LUNA measurements

25Mg(p,)26Al - HPGe spectra ER = 190 keV

75 C

Iliadis et al, 1990

25Mg(p,)26Al - HPGe spectra ER = 190 keV

BR0 = (75 ± 2) %

75 C

wg [eV] LUNAHPGe

wg [eV] LUNABGO

wg [eV] Iliadis et al. 1990

(9.0 ± 0.7)10-7 (9.0 ± 0.8)10-7 (7.4 ± 1.0) 10-7

25Mg(p,)26Al - BGO spectra ER = 92 keV

The BGO g-ray total sum spectrum on the 92 keV 25Mg(p,g)26Al resonance (Ep = 100 keV). 1. The shaded area envinromental background2. Thin solid line 25Mg(p,g)26Al simulation varying the primaries branchings .3. Solid red line total yield fit including background and simulation.

Background run done @ Ep = 86.5 keV

wg [10-10 eV] LUNA

wg [10-10 eV] NACRE ind.

2.9 ± 0.6 1.16 +1.16 -0.39

the lowest ever directly measured resonance strength

Ex (keV) Jp

6399

0

2+

5+

25Mg+p

26Al level scheme

228 0+

26Al0

26Alm

BR0 = (60 +20-10) %

25Mg(p,)26Al - ER = 92 keV branchings

Champagne et al. Nucl. Phys. A 402(1983)

BR0 = (81 ± 1) %

BR0 = (60 +20-10) %

25Mg(p,)26Al - Astrophysical consequences

LUNA results fully cover the temperature range of core massive main sequence stars (Wolf-Rayet) as well as the H-burning shell of RGB and AGB stars.

50 MK < T < 140 MK30-40 % larger

factor 5 larger

About factor 2 larger

50 MK < T < 140 MK

In press in ApJ

25Mg(p,)26Al - Astrophysical consequencesWR stars: NA<sv>total factor 2 > NACRE and Iliadis NA<sv>isomeric factor 5 > NACRE and Iliadis the expected production of 26Algs in stellar H-burning zones is lower than previously estimated. This implies a reduction of the estimated contribution of WR stars to the galactic production of 26Al.

Presolar grains originated in AGB stars: the most important conclusion is that the deep AGB extra-mixing, often invoked to explain the large excess of 26Al in some O-rich grains, does not appear a suitable solution for 26Al/27Al> 10−2.

Mg-Al anti-correlation in Globular Clusters stars: the substantial increase of the total reaction rate makes the Globular Cluster self-pollution caused by massive AGB stars a more reliable scenario for the reproduction of the Mg-Al anti-correlation.

Preliminary, submitted to ApJ

17O(p,)18F - Astrophysical motivation

• Classical Novae nucleosythesis (T=0.1-0.4 GK):

1. production of light nuclei (17O/18O abundances....);

2. observation of 18F g-ray signal (annihilation 511 keV).

1.00E+07 1.00E+08 1.00E+090%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%DC/tot 65/tot

183/tot 489.9/tot

529.9/tot Broad res/tot

T [K]

NA

<ss>

i/N

A<s

v>to

t17O(p,)18F – LUNA experiment

LUNA is directly investigating this energy window

Broad resonaces - - - - -DC component -·-·-·-·-Total

556 keV 767 keV

Caciolli et al., submitted to EPJ A

17O(p,)18F – On and off resonance spectra

Off-Resonance

On-Resonance

To be published, courtesy of A. Formicola on behalf of the working group

New transitions observed on resonance!

• Total reaction Cross section measured between Ecm ≈ 180 – 370 keV measured leading to a four-fold reduction in reaction rate uncertainty.

• Resonance Strength of Ep=193 keV resonance measured within an uncertainty of 7%. (~factor 2 higher accuracy).

Preliminary Results17O(p,)18F – S-factor

D. Scott et al. Accepted PRL

• Total reaction Cross section measured between Ecm ≈ 180 – 370 keV measured leading to a four-fold reduction in reaction rate uncertainty.

• Resonance Strength of Ep=193 keV resonance measured within an uncertainty of 7%. (~factor 2 higher accuracy).

Preliminary Results17O(p,)18F – Reaction rate

D. Scott et al. Accepted PRL1.00E+07 1.00E+08 1.00E+090%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100% DC/tot65/tot183/tot489.9/tot529.9/totBroad res/tot

T [K]

NA

<ss>

i/N

A<s

v>to

t_

17O(p,)18F – The problem of the DC extrapolation towards lower energies

C. Rolfs, Nucl. Phys. A217 (1973) 29

Kontos et al., submitted to PRCR-

mat

rix a

naly

sis

with

AZU

RE c

ode

expe

rimen

t per

form

ed in

ND

LUNA 400 kV outlook

400 kV 2008

CNO CYCLE

NeN

a C

YC

LE

20Ne 23Na

(p,

)g

(p, )a

22Na

22Ne

(p, )g

e+n

3 yr

21Ne

21Na

(p,

)g

e+n

22 s12C 15N

13C 14N

13N 15O

(p,

)g

(p, )g

(p,

)g

(p, )a

e+n

e+n

6×10

9 y

1×109 y2×10

12y2 m

1×108 y

10 m

CN

16O

17O

17F

(p, )a

(p,

)g

e+n

64 s

NO

(p, )g18O

18F(p, )g

e+n

108 m

(p, )a19F

(a, )g

(p, )g

(p, (p, )g24Mg

(p,

27Al(p,

27Si

(p,

e+ 4 s

26Al

26Mg

(p,

e+

6 s

25Mg

25Al

(p,

e+

7 s

MgAl CYCLE

The Luna CollaborationINFN, Laboratori Nazionali del Gran Sasso A. Formicola, M. JunkerINFN, Section of Genoa F. Cavanna, P. Corvisiero, P. PratiINFN, Section of Milan A. Guglielmetti (SP), D. TrezziINFN, Section of Naples A. Di Leva, G. Imbriani, E. Roca and F. TerrasiINFN, Section of Padua C. Broggini, A. Caciolli, R. De Palo,R.MenegazzoINFN, Section of Roma 1 C. GustavinoINFN, Section of Turin G. GervinoINAF, Teramo observatory O. StranieroRuhr-Universität Bochum, Germany C. Rolfs, F. Strieder, H. P. TrautvetterForschungszentrum Dresden-Rossendorf, Germany M. Anders, D. Bemmerer, Z. Elekes Atomki Debrecen, Hungary Zs. Fulop, Gy. Gyurky, E. Somorjai,T. SzucsThe University of Edinburgh, UK M. Aliotta, T. Davinson, D. A. Scott

Accelerator Specifications

U = 50 – 400 kV

I 500 mA for proton

DEmax= 0.07 keV

Energy spread : 72eV

Total uncertainty is 300 eV for Ep=100 400keV

Solid target + HPGe detector Gas target + BGO detector

TiN (1/(1.08 ± 0.05)) targets

14N(p,g)15O @ LUNA

Natural and enriched evaporated targets on Ta backing, starting from MgO powder

Target study and normalization procedure

Oxygen content determination via RBS on natural Mg target. Using a natural target with known Oxygen content

and stoichiometry we measured of 24,25,26Mg(p,)25,26,27Al at

Ecm = 214, 304, and 326 keV resonances with HPGe (@ 42 cm) and BGO setup →

normalization for low-energies

wg

400 kV 2006

p + p 2H + e+ + n [0.27 MeV] p + e- + p 2H + n [1.44 MeV]

2H + p 3He + g

3He + 3He 4He + 2p 3He + 4He 7Be + g 3He + p 4He + e+ + n

7Be + e- 7Li + n [0.81 MeV] 7Be + p 8B + g

7Li + p 8Be 8B 8Be + e+ + n [6.80 MeV]

8Be 2 4He 8Be 2 4He

0.11%99.89%

LUNA program: pp chain

99.75% 0.25%

86% 14%

CHAIN IIIQeff= 19.67 MeV

CHAIN II Qeff= 25.66 MeV

CHAIN IQeff = 26.20 MeV

CHAIN IVQeff= 16.84 MeV

2·10-5% 50 kV 2001

50 kV 1999

LUNA program: CNO and MgAl chains

24Mg

(p,

27Al(p,

27Si

(p,

e+ 4 s

26Al

26Mg

(p,

e+

6 s25Mg

25Al

(p,

e+

7 s

400 kV 2004

400 kV 2010

400 kV 2012

400 kV 2008

E ~ kT

nuclear well

V

rrn

T ~ 15x106 KE = kT ~ 1

keV

EC = 550

keV

during quiescent burnings: kT << Ec

reactions occur through

TUNNEL EFFECT

projectile

rezz

rVC

221)(

EC ~ z1z2

z1 z2

Example z1=p and z2=p (e.g. in the Sun)

1E-20

1E-16

1E-12

1E-08

1E-04

s [

b]

023

21

dEkTE

EexpEkT

1πμ8

σv s

Charged particle reaction in stars

reactionCoulomb

barrier (keV)

EG

(keV)

p + p 550 5.9

+ 12C 3430 56-20016O + 16O 14070 200-500

HpGe spectrum Ecm= 230keV

BGO spectrum Ecm= 140keV

G. Imbriani, et al., EPJA 25(2005)

D. Bemmer, et al. NuPhyA 779(2006)

14N(p,g)15O: g-spectraSolid target + HPGe detector

Gas target + BGO detector

Ex (keV)

6791

6172

5180

0

ECM (keV)

Q = 7297

14N + p

15O

7540

Lowest energy HpGe spectrum Ecm=110keV Lowest energy BGO spectrum Ecm=70keV

A. Formicola et al ., PhLB 591(2004)G. Imbriani, et al., EPJA 25(2005)M. Marta et al., PRC 78 (2008)

D. Bemmer, et al. NuPhyA 779(2006)Lemut, et al. PhLB, 634(2006)

14N(p,g)15O: g-spectra and S(0)

DIRECT MEASUREMENTS INDIRECT MEASUREMENTS Review

EX [keV]

Schröeder et al.NuPhA 467(1987)

LUNA *

LENA PRL 94(2005)

Mukhamedzhanov et al.PRC 67(2005)

Nelson et al.PRC 68(2003) Solar Fusion II

0 1.55 ± 0.34 0.25 ± 0.06 0.15 ± 0.07 0.15 ± 0.07 0.27 ± 0.055183 0.010 ± 0.003 0.010 ± 0.0035241 0.070 ± 0.003 0.070 ± 0.0036173 0.14 ± 0.05 0.08 ± 0.03 0.13 ± 0.02 0.15 ± 0.07 0.15 ± 0.07 0.13 ± 0.06 6793 1.41 ± 0.02 1.20 ± 0.05 1.4 ± 0.2 1.40 ± 0.20 1.18 ± 0.05tot (3.20 ± 0.54) (1.61 ± 0.08) (1.68 ± 0.09) (1.70 ± 0.22) (1.66 ± 0.08)

1.E-02

1.E-01

1.E+00

1.E+01

1.E+02

1.E+03

0 50 100 150 200 250 300 350 400 450

E [keV]

S-f

ac

tor

[ke

V b

]

Stot (keV b)

gas target

gs

6.79

6.17

5.24

5.18

LUN

A/N

ACRE

14N(p,g)15O: reaction rate

Ex (keV)

6791

6172

5180

0

ECM (keV)

Q = 7297

14N + p

15O

7540