1. Stato dell'esperimento LUNA
marzo 2015
Laboratory Underground Nuclear Astrophysics
Alessandra Guglielmetti
Università degli Studi di Milano e
INFN, Milano, ITALY
Risultati recenti: 17O(p,a)14N (coordinatrice Alba Formicola), 18O(p,a)15N (coordinatrice Marialuisa Aliotta), 22Ne(p,g)23Na fase HPGe (coordinatore Daniel Bemmerer)
Misure in corso: 22Ne(p,g)23Na fase BGO (coordinatore Antonio Caciolli), 23Na(p,g)24Mg (coordinatore Gianluca Imbriani), 18O(p,g)19F (coordinatore Andreas Best), 2H(p,g)3He (coordinatore Davide Trezzi)
Collaborazione attuale e contatti in via di definizione
Stato del progetto LUNA MV

2. The 17O(p,a)14N reaction: astrophysical motivation
Influence 17O abundance in several stellar sites
In AGB stars ( T= GK )
CNO cycle takes place in core of star only
Measured 17O/16O abundance in pre-solar grain give information on AGB surface composition: higher 17O quantity with respect to predictions
Information on mixing processes if cross section is well known

3. The 17O(p,a)14N reaction: nuclear physics aspects
Q-value = 1.2 MeVexpected alpha energy 1 MeV
Two narrow resonances at 70 and 193 keV (lab)

4. The 17O(p,a)14N reaction: state of the art
193 keV Resonance:
Authors
Resonance strength
Approach
Chafa ( )
(1.6±0.2) x10-3 eV
Activation
Moazen (2007)
(1.70±0.15) x10-3 eV
Direct (inverse kinematics)
Newton ( )
(1.66±0.17) x10-3 eV
Direct
Our goal!
70 keV Resonance:
Berheide (1992)
< 8x10-10 eV
Direct (upper limit)
Blackmon (1995)
x10-9 eV
Direct
Sergi (2010)
x10-9 eV
Indirect (Trojan horse)

5. The 17O(p,a)14N reaction: experimental setup
Silicon detector
proton beam from LUNA 400 kV
enriched 17O targets
8 silicon detectors
foils of Al Mylar to stop backscattered protons low alpha particle energy ( keV)
Solid target position

6. The 17O(p,a)14N reaction: 193 keV res
1-2 alphas/s/detector at ~250 keV
clear peak visible in spite of low energy and rate
In agreement with literature!

7. The 17O(p,a)14N reaction: 70 keV res
Evidence of a counting excess in the region of interest!

8. The 17O(p,a)14N reaction: 70 keV res
PRELIMINARY
-expected energy
-expected width
-significance >5 sigma

9. The 17O(p,a)14N reaction: 70 keV res
PRELIMINARY
Very preliminary analysis favours a larger strength value compared with literature
If confirmed, it would have an astrophysical impact
Analysis is still ongoing…

10. The 18O(p,a)15N reaction: astrophysical motivation
Synthesis of 15N, 18O, 19F in novae and AGB stars
In AGB stars ( T= GK )
CNO cycle takes place in core of star only
Measured 18O/16O abundance in pre-solar grain give information on AGB surface composition: lower 18O quantity with respect to predictions
Information on mixing processes if cross section is well known

11. The 18O(p,a)15N reaction: nuclear physics aspects
Qvalue = 4 MeV
expected alpha energy
MeV

12. The 18O(p,a)15N reaction- state of the art and objectives
Re-scan excitation function: Any new resonance?
95 keV resonance: strength? Resonance energy [(96.6 ± 2.2) keV (La Cognata 2008)]
Measure below 70 keV beam energy: Closer to Gamow peak. Low counting rate

13. The 18O(p,a)15N reaction: excitation function
Data taking completed. Data analysis on going
152 keV resonance
334 keV resonance
216 keV resonance
In agreement with previous data
Might improve precision on resonance energy and strength

14. The 18O(p,a)15N reaction:96 keV resonance and below:
Precision about 10% (30% literature). Resonance energy determined
with 0.5 keV precision (3 keV literature)
Data below 70 keV not fully analysed yet. Necessary R-matrix fit

15. The 18O(p,a)15N reaction:low energies
Plot shows 50% statistic for only one detector out of four
Very clear peaks at Ep = 70 and 65 keV
Peak at Ep = 60 keV visible. Lowest direct data point in literature.
Expected ~20% statistical uncertainty at 60 keV from full analysis
PRELIMINARY
18O(p,α)
alpha peak

16. The 22Ne(p,g)23Na reaction: astrophysical motivation
NeNa cycle of H burning. Active in astrophysical novae
Impact on the abundances of: 22Ne (factor 100) 23Na (factor 7) 24Mg (factor 70)

17. The 22Ne(p,g)23Na reaction
The resonances within the “green” box have been investigated
The “red” resonances have been directly observed for the first time
For the resonances at 71, 105 and 215 keV in “black” an upper limit has been found

18. The 22Ne(p,g)23Na reaction: ERlab=259.7 keV
1919
Branching
The 22Ne(p,g)23Na reaction: ERlab=259.7 keV
γ-transition
Eγ [keV]
Branching [%]
R→440
8602
47.4 ± 0.8
R→2076
6963
19.4 ± 0.6
R→2704
6335
11.4 ± 0.5
R→3848
5193
13.9 ± 0.6
R→3914
5127
1.5 ± 0.3
R→5927
3115
3.9 ± 0.2
R→6042
3000
2.6 ± 0.2
R→6354.5
2686.5
1.5 ± 0.2
R→6820
2221
2.2 ± 0.2
New gamma decay modes discovered. Branching ratios determined

19. The 22Ne(p,g)23Na reaction: results
ERlab [keV]
ωγ [eV]
LUNA
direct experiment [Gӧrres82]
indirect experiment [Hale02] 71 ≤ ≤ ≤
105 ≤ ≤ ≤
156.2
[1.48 ± 0.09 (stat) ± 0.04 (syst)] 10-7 ≤ ≤
189.5
[1.87 ± 0.03 (stat) ± 0.05 (syst)] 10-6 ≤
215 ≤ ≤
259.7
[6.89 ± 0.08 (stat) ± 0.14 (syst)] 10-6 ≤
3 resonances observed for the first time
The new upper limits on 71, 105 and 215 keV resonances are 2 orders of magnitude (or more) lower compared to the previous direct measurement

20. On going (from last week): the 22Ne(p,g)23Na reaction BGO phase
Aim: measure or improve upper limits for 71 and 105 keV resonances. Check the 156 keV resonance to compare with HPGe phase
Measure DC component at 200, 280 and 360 keV

21. The 22Ne(p,g)23Na reaction BGO phase
Pressure and temperature profiles in the gas target measured with and without gas… one ingredient!

22. On going: the 23Na(p,g)24Mg reaction
NeNa Cycle
20Ne
23Na
(p,g)
(p,a)
22Na
22Ne
e+n
3 yr
21Ne
21Na
22 s
19F
(p,
24Mg
27Al
(p,
27Si
e+
4 s
26Al
26Mg
6 s
25Mg
25Al
7 s
MgAl Cycle
23Na(p,g)24Mg is the bridge between NeNa cycle and MgAl cycle.
Important for AGB stars

23. The 23Na(p,g)24Mg reaction: nuclear physics aspects and state of the art
AGB stars T= 70 MK
E=138 keV resonance (Ep=144 keV)
wg Cesaratto ≤ 5.2 neV
(2 neV ?)

24. 23Na(p,g)24Mg reaction: measurement plan
BGO measurement of:
Ep= 250, 308 keV (calibration)
DC component
Ep=144 keV (according to Cesaratto “strength limit” about 80 events/day with I=100 mA)
High efficiency. Gamma-ray summing moves signal away from natural background
Total time about 6 months
HPGe measurement if feasible
Targets: evaporated Na2WO3 (Notre Dame, Atomki)
metallic Na pressed between two backings (Napoli)
Need to check stability under beam

25. 23Na(p,g)24Mg reaction: lead shielding
Few massive pieces:
For BGO about 10 cm
For HPGe about 20 cm (both at 0° and 55°)
Movable on rails. Easy access to target
Gamma shielding effective

26. On going (in parallel) 18O(p,g)19F reaction
Oxygen depletion in low-mass AGB star atmospheres (T=40 MK) and in 15% of all pre-solar grains possibly explained through enhanced 18O(p,g)19F at low temperatures?
95 keV negligible
Bruckner 2012
95 keV dominant
Fortune 2013
(95±3) keV: energy uncertainty has large effect on rate uncertainty

27. 18O(p,g)19F reaction: measurement plan
BGO measurement of:
E= 95 keV resonance
DC component
HPGe measurement of:
E=95 keV branching ratios (if feasible)
High energy DC component
Same experimental setup of 23Na(p,g)24Mg. Enriched 18O targets produced by anodization (Ta2O5) in LNGS

28. The 2H(p,γ)3He reaction
Total amount of deuterium produced in the early Universe depends on the cosmological parameters and on the nuclear cross sections of the reactions involved (main source of uncertainty 2H(p,γ)3He).
BBN predictions (PLANCK+SFII)
2H/H = (2.65 ± 0.07) x 10-5
ASTRONOMICAL observations
2H/H = (2.53 ± 0.04) x 10-5
Poor data in the BBN energy range ( keV). Try to reduce uncertainty from 9 to 3%
10% disagreement between nuclear theory (ab-initio calculations) and experimental data. New calculations in 20% disagreement

29. The 2H(p,γ)3He test (October 2014)
Test of the reaction using a setup similar to the one used for the 22Ne(p,g)23Na.
Gas target filled with 2H (0.3 mbar), no recirculation
136% HPGe detector at 90°with respect to the beam

30. The 2H(p,γ)3He test (October 2014)
Runs at literature (Ma et al.) energies keV (maximum LUNA energy) keV (19F(p,ag)16O reaction resonance).
Low level beam induced background (Carbon and Fluorine contamination)
No deuterium implantation
Good agreement between data and simulations → Differential cross section at low energies
Data analysis in progress

31. The 2H(p,γ)3He reaction
Test program accomplished except for the HPGe efficiency measurement (estimated with Montecarlo simulations)
Measurement campaign planned for the end of 2015-beginning of 2016:
-BGO phase → Using the 22Ne BGO setup (low-medium energy range)
-HPGe phase → Using a new setup (under R&D) (high-medium energy range)
Solid targets under investigation.

32. The LUNA collaboration (1)
A. Best, A. Boeltzig*, A. Formicola, S. Gazzana, I. Kochanek, M. Junker, L. Leonzi | INFN LNGS /*GSSI, Italy
D. Bemmerer, M. Takacs, T. Szucs | HZDR Dresden, Germany
C. Broggini, A. Caciolli, R. Depalo, R. Menegazzo, D. Piatti | Università di Padova and INFN Padova, Italy
C. Gustavino | INFN Roma1, Italy
Z. Elekes, Zs. Fülöp, Gy. Gyurky| MTA-ATOMKI Debrecen, Hungary
O. Straniero | INAF Osservatorio Astronomico di Collurania, Teramo, Italy
F. Cavanna, P. Corvisiero, F. Ferraro, P. Prati, S. Zavatarelli | Università di Genova and INFN Genova, Italy
A. Guglielmetti, D. Trezzi | Università di Milano and INFN Milano, Italy
A. Di Leva, G. Imbriani, | Università di Napoli and INFN Napoli, Italy
G. Gervino | Università di Torino and INFN Torino, Italy
M. Aliotta, C. Bruno, T. Davinson | University of Edinburgh, United Kingdom
G.F. Ciani, G. D’Erasmo, E.M. Fiore, V. Mossa, F. Pantaleo, V. Paticchio, R. Perrino, L. Schiavulli, A. Valentini| Università di Bari and INFN Bari, Italy

33. The LUNA collaboration (2)
23Na(p,g)24Mg reaction:
J. De Boer, M. Wiescher | Notre Dame University, USA (High energy measurements and R matrix calculations)
L. Gialanella, R. Buompane, L. Gasques | Seconda Università di Napoli and INFN Caserta, Italy (ERNA/CIRCE collaboration) (Measurement of the 23Na(p,a)20Ne competing reaction at CIRCE collaboration with LUNA members).
2H(p,g)3He reaction:
L. Marcucci, A. Kievsky and M. Viviani | Università di Pisa and INFN Pisa, Italy (ab initio calculations)

34. The LUNA collaboration (3)
LUNA MV- Under definition
Z. Janas, C. Mazzocchi et al., Warsaw University, Poland
K. Czerski et al., Szczecin University, Poland

35. LUNA MV project
LUNA MV accelerator will be installed in the south part
of Hall C of LNGS laboratory (OPERA location)
Provisionary dimensions of the hall: 27x11x5 m3
Opera decommissioning started in Jan 2015 To be finished by October (S. Gazzana link to LUNA MV)

36. LUNA MV project Accelerator:
Intense H+, 4He+, 12C+ e 12C++ beams in the energy range: 350 keV-3.5 MeV. One beam line with all necessary elements (magnets, ..).
Total budget about 3.9 Meuro: from LUNA MV Premium projects (total 5.3 Meuro)
Tendering procedure («procedura ristretta»): full documentation submitted to INFN central administration at end of february 2015 (for the INFN Executive Board and Directorate meetings of March 2015)
Tender assignment: 50% tecnical performances (beam intensity, beam quality, maintenance, additional components, …) , 50% price
RUP: G. Imbriani, Università di Napoli
DEC & designer: M. Junker, LNGS

37. LUNA MV project: INFN executive board
March 18th, 2015

39. LUNA MV-timeline Accelerator tender: Contract signed by 12/2015.
Accelerator built and tested by the producing company by 11/2017.
Accelerator installed at LNGS and tested by 07/2018. Then first experiments
Building & shielding:
final solution to be defined by June 2015.
GEANT4 simulations with different materials are under development in order to find out the best compromise among performance as neutron shield, price, easiness of decommissioning, thickness (maximize internal space, …
Plants:
to be defined by December 2015
From January 2016 start of tendering for building & shielding and plants

40. LUNA MV- organigram PI Guglielmetti Prati GLIMOS Gazzana RAE
Coord of authorization request
Prati
GLIMOS
Gazzana
RAE
Gas target beam line
Solid target beam line
Imbriani
Gamma detectors & DAQ
Menegazzo
Neutron detectors & DAQ
Paticchio
Neutron simulation
Trezzi
Plants
Civil engineering
Building & Infrastructure
Accelerator
Junker/ Imbriani
Scientific equipments
Formicola
Accelerator advisory committee
RUP support office
Technical coordinator