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)

e–2ph
Reaction Rate(star)  F(E) s(E) dE
Gamow Peak
Maxwell
Boltzmann
s
E-1
Extrap.
Meas.
F
= 0.7 m-2 h-1
F
-6 cm-2 s-1

310
n
luna
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
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
pp chain
p + p  d + e+ + n e
d + p  3He + g
84.7 %
3He
13.8 %
+3He  a+2p 3He +4He  7Be + g
0.02%
13.78 %
7Be+e- 7Li
7Li
7Be
+ g +ne
+p  a + a
8B
0,57
2a + e++ ne
activation-PRL+PRC
activation
0,55
S(E) [keV b]
+ p  8B + g
on-line
0,53
0,51
0,49
0,47
0,45
80
100
120
140
Ecm [keV]
160
180
278
7556
1/2
7/2
+
5/2
+
-21
6859
6793
3/2
+
- 504
6176
3/2
-
5241
5/2
+
5183
1/2
+
1/2
-
7297
7276
14N+p
14N(p,g)15O
+
Q=7.3 MeV
15O
0
25Mg(p,g)26Al
304
Ex (keV)
6598
190
6496
130
6436
4-
92
6399
2-
ECM (keV)
Novae explosive
Burning (T9>0.1)
AGB or W-R
Stars (T9~0.05)
Jp
5+
5+
No direct strength
resonance data
(level structure derived from
the singe particle transfer
reaction: 25Mg(3He,d)26Al)
Q = 6306 keV
25Mg+p
Astrophysical sites
AGB stars;
 Novae;
 Massive stars.
Motivation
Nucleosintesis of the elements
0+ 24<A<27
 5+ Astronomical interest of
1809 keV 26Mg g line

26Alm
26Al0
228
0
What else can be done with LUNA II (400kV) ?
CNO
Ne-Na
BBN
reaction
Q-value
(MeV)
Gamow energy
(keV)
15N(p,g)16O
12.13
10-300
130
50
17O(p,g)18F
5.6
35-260
300
65
18O(p,g)19F
8.0
50-200
143
89
23Na(p,g)24Mg
11.7
100-200
240
138
22Ne(p,g)23Na
8.8
50-300
250
68
1.47
50-300
700(direct)
50(indirect)
50
D(a,g)6Li
Lowest meas.
Energy (keV)
proposal submitted to INFN (2008-2012)
LUNA limit
2H(a,g)6Li
Q=1.47 MeV
Burning energy: 50-300 keV
12C(a,g)16O
•MV-accelerator
•12C-enriched targets
•Beam intensity: 500A
•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
Reactions powering the astrophysical sprocess
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 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
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(a,g)7Be
Q=1.6 MeV
Solar Neutrinos:7Be,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 < 5 %
Summary of previous measurements
0,8
on-line g - measurements
<S34(0)> = 0.51 ± 0.02 keV b
activation measurements
<S34(0)> = 0.57 ± 0.03 keV b
S34(0) [keV
0,7
activation
average
0,6
on-line g - meas.
average
0,5
0,4
Nagatani et. al.
1969
Robertson et. al.
1983
Volk et. al.
1983
Osborne et. al.
1982
Hilgemeier et. al.
1988
Osborne et. al.
1982
Nara Singh et. al.
2004
Alexander et. al.
1984
Parker et. al.
1963
KrŠ
winkel et. al.
1982
Hilgemeier et. al.
1988
0,3
Recommended S34(0) values:
R-matrix analysis:
0.53 ± 0.05 keV b (9%) [Adelberger 98]
0.54 ± 0.09 keV b (16%) [NACRE 99]
0.51 ± 0.04 keV b (8%) [Descouvemont 2004]
Activation
measurement
o 4He beam @ 350 keV
o <I> ~ 230 µA
o Recirculated 3He @ 0.7 mbar
T½ =52.2±1.5 d
Prompt g-spectra
o 4He beam @ 400 keV
o <I> ~ 300 µA
o Irradiation time: 4.4d
o 4He beam @ 220 keV
o <I> ~ 240 µA
o Irradiation time: 24.4d
0,57
activation-PRL+PRC
activation
S(E) [keV b]
0,55
on-line
0,53
0,51
0,49
0,47
0,45
80
100
120
140
Ecm [keV]
ΔS = -1.4  4.2 %
160
180
S34(0) = 0.560  0.017 keV barn
s
of 3He(a,g)7Be down to 93 keV
7Be ≈ prompt g
S34(0) = 0.560  0.016 keV barn
ΔΦ(nB) reduced from 12% to 10%
ΔΦ(nBe) reduced from 9.4% to 5.5%
(C. Pena Garay)
LUNA
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, RuhrUniversität Bochum (GE)
•Atomki Debrecen (Hungary)
0.45%
HPGe Efficiency
0.40%
511 keV
662 keV
1173 keV
1275 keV
1332 keV
0.35%
Efficienza %
0.30%
0.25%
0.20%
0.15%
0.10%
0.05%
0.00%
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
32
34
36
ACTIVITY
7Be
counting efficiency
PROMPT-g
1.8%
Beam intensity
1.5%
Target density
1.5%
Beam intensity
1.5%
Beam heating effect
1.3%
Target density without
beam
0.6%
3He
purity
0.1%
7Be
0.5%
Efficiency
1.5%
Angular distribution
1.5%
backscattering
Incomplete 7Be collection
0.4%
7Be
0.4%
distribution in catcher
478 keV branching
0.4%
7Be
half-life
0.1%
3He
purity in target
0.1%
25Mg(p,g)26Al
Q=6.3 MeV
Nucleosynthesis Mg-Al
Astronomical interest of the g from
26Al decay
•Cross section at 180-400 keV with Ge detectors
•Cross section down to 90 keV with BGO summing
crystals
Turbo
Pump
1”x1”NaI(Tl)
4 BGO Detector
Target incl
LN2 Trap and
H2O cooling
Lead
shielding
LN2 Trap
(Isolated)
Gate Valve
Faraday Cup
Beam Profile
Monitor
4 Slits
Wobblers
Bellow
*
ncno
from the Sun
* Globular cluster age
* C yield in AGB stars
15N(p,g)16O
Q=12.13 MeV