Carlo Broggini, INFNPadova

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LUNA beyond the Sun
Carlo Broggini, INFN-Padova
Men in pits or wells sometimes see the stars.
Aristotle

• Nuclear Burning
• in Stars
• s(Estar)

s(E) S(E) e2ph E-1
?
Reaction Rate(star) ?
F(E) s(E) dE
Extrap.
Meas.
Gamow Peak
s
Maxwell Boltzmann
s
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F?
Fn

0.7 m-2 h-1
? 3?10-6 cm-2 s-1
luna
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LUNA2 (400 kV)
LUNA1 ( 50 kV)
Voltage Range 50-400 kV
Output Current 1 mA (_at_ 400 kV)


Absolute Energy error 300 eV Beam
energy spread lt100 eV Long term stability (1 h)
5 eV Terminal Voltage ripple 5 Vpp Ge detector
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
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278
7556
1/2
7297
7276
7/2
14Np
6859
5/2
-21
6793
3/2
- 504
6176
3/2 -
14N(p,g)15O
5241
5/2
5183
1/2
Q7.3 MeV
15O
0
1/2 -
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25Mg(p,g)26Al
Ex (keV)
J?
ECM (keV)
5
6598
304
5
Novae explosive Burning (T9gt0.1)
6496
190
130
6436
4-
AGB or W-R Stars (T90.05)
92
6399
2-
No direct strength resonance data (level
structure derived from the singe particle
transfer reaction 25Mg(3He,d)26Al)
Q 6306 keV
25Mgp

• Astrophysical sites
• AGB stars
• Novae
• Massive stars.

228
0
26Alm
0
5
26Al0
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What else can be done with LUNA II (400kV) ?
CNO
Ne-Na
BBN
proposal submitted to INFN (2008-2012)
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2H(?,g)6Li
Burning energy 50-300 keV
Q1.47 MeV
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12C(a,g)16O

• MV-accelerator
• 12C-enriched targets
• Beam intensity 500mA
• Detection efficiency 50 total 2.5
  single segment (angular distributions)
• Detection set-up scintillator-crystal ball

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
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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

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Accelerator
Accelerator requirements MV electrostatic
accelerator Option 1 HVEE conventional RF ion
source Option 2 NEC ECR high charge state ion
source Two possible layouts
letter of intent submitted to LNGS
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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
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3He(?,g)7Be
Q1.6 MeV

• Solar Neutrinos7Be,8B
• BBN 7Li

• Cross section from prompt gamma down to
• 90 keV (CM energy) using 4He beam on 3He
• target
• Activation via off-line radioactive decay
• measurements of the 7Be atoms collected
• in the beam catcher
• All with a final error lt 5

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Summary of previous measurements
ltS34(0)gt 0.51 0.02 keV b
ltS34(0)gt 0.57 0.03 keV b
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Activation measurement

• 4He beam _at_ 350 keV
• ltIgt 230 µA
• Recirculated 3He _at_ 0.7 mbar

T½ 52.21.5 d
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Prompt ?-spectra

• 4He beam _at_ 400 keV
• ltIgt 300 µA
• Irradiation time 4.4d

• 4He beam _at_ 220 keV
• ltIgt 240 µA
• Irradiation time 24.4d

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?S -1.4 ? 4.2
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S34(0) 0.560 ? 0.017 keV barn
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• s of 3He(?,g)7Be down to 93 keV
• 7Be prompt g

• S34(0) 0.560 ? 0.016 keV barn
• ?F(?B) reduced from 12 to 10
• ?F(?Be) reduced from 9.4 to 5.5
• (C. Pena Garay)
  

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LUNA
INFN - Laboratori Nazionali del Gran
Sasso D.Bemmerer,R.Bonetti,C.Broggini,F.Confortol
a,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)
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HPGe Efficiency
Efficienza
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ACTIVITY
PROMPT-?
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25Mg(p,g)26Al
Q6.3 MeV

• Nucleosynthesis Mg-Al

• Astronomical interest of the ? from
• 26Al decay

• Cross section at 180-400 keV with Ge detectors
• Cross section down to 90 keV with BGO summing
  crystals

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Target incl LN2 Trap and H2O cooling
LN2 Trap (Isolated)
Beam Profile Monitor
Lead shielding
Faraday Cup
Gate Valve
Wobblers
Bellow
4 Slits
1x1NaI(Tl)
4? BGO Detector
Turbo Pump
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?cno from the Sun Globular cluster age C
yield in AGB stars
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15N(p,g)16O
Q12.13 MeV
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