L’esperimento LUNA- CdS MI luglio 2012 Alessandra Guglielmetti Università degli Studi di Milano e INFN, Milano, ITALY Laboratory Underground Nuclear Astrophysics  L’esperimento LUNA: misure recenti  Il Progetto LUNA MV: progetto premiale

LUNA site LUNA 1 ( ) 50 kV LUNA 2 (2000  …) 400 kV Laboratory for Underground Nuclear Astrophysics Nuclear Astrophysics RadiationLNGS/surface Muons Neutrons LNGS (shielding  4000 m w.e.) LUNA MV 2012 ?

p + p  d + e + + e d + p  3 He +  3 He + 3 He   + 2p 3 He + 4 He  7 Be +  7 Be+e -  7 Li +  + e 7 Be + p  8 B +  7 Li + p   +  8 B  2  + e + + e 84.7 %13.8 % % 0.02 % pp chain LUNA results: Hydrogen burning (1)

LUNA results : Hydrogen burning (2) (p,  24 Mg (p,  27 Al (p,  27 Si (p,  e + 4 s 26Al 26 Mg (p,  e + 6 s 25 Mg 25 Al (p,  e + 7 s (p,  4p  4 He + 2e e MeV

2 H( ,  ) 6 Li measurement :the 6 Li case Constant amount in stars of different metallicity (  age) 2-3 orders of magnitude higher than predicted with the BBN network (NACRE) (Asplund 2006, now debated since convective motions on the stellar surface can give an asymmetry in the absorption line mimicking the presence of 6 Li) The primordial abundance is determined by: 2 H( ,  ) 6 Li producing almost all the 6 Li 6 Li(p,  ) 3 He destroying 6 Li  well known 6 Li 7 Li BBN prediction

[F. Hammache et al., Phys. Rev. C 82, (2010)] Direct measurements:  Robertson et al. E > 1 MeV  Mohr et al. around the 0.7 MeV resonance Indirect measurements: Hammache et al. upper limits with high energy Coulomb break-up At LUNA direct measurements at the energies of astrophysical interest 2 H( ,  ) 6 Li : available data

2 H( ,  ) 6 Li : the beam-induced background d d n n 3 He α α α α d d d d - neutron background generated by d( ,  )d Rutherford scattering followed by d(d,n) 3 He reactions -> (n,n’γ) reactions on surrounding materials (Pb, Ge, Cu) -> much higher γ-ray background in the RoI for the d(α,γ) 6 Li DC transition (~1.6 MeV)

Reduced gas volume: pipe to minimize the path of scattered 2 H and hence diminish the d(d,n) 3 He reaction yield HPGe detector in close geometry: larger detection efficiency and improved signal-to-noise ratio Silicon detector to measure 2 H( 2 H,p) 3 H and thus monitor n production 2 H( ,  ) 6 Li : experimental set-up

2 H( ,  ) 6 Li data taking Two measurement campaigns: spring and fall 2011 Intense alpha beam (  1000 C in total) on D 2 gas target at 0.3 mbar 280 keV and 400 keV (240 keV and 360 keV). Noise/signal ratio very unfavourable (  20 at 400 keV) Measurement strategy: E  = Q + E CM -  E rec ±  E Doppler Measurement with  beam on 2 H gas target at 400 keV ROI: keV Measurement with  beam on 2 H gas target at 280 keV ROI: keV Subtraction of the two "normalized" spectra. Three different and independent analysis are being carried out. Similar results (still preliminary!)

2 H( ,  ) 6 Li: preliminary results (1) Counting excess observed in the E CM =134 keV ROI (red)

2 H( ,  ) 6 Li :preliminary results (2) Counting excess shifted in the E CM =120 keV ROI (violet)

17 O(p,  ) 18 F measurement 17O+p is very important for hydrogen burning in different stellar environments: - Red giants - Massive stars - AGB - Novae (Cygni 1992) Annihilation 511 keV gamma- rays following β + decay of 18 F (t 1/2 =110 min)  potential constraints on current novae models Classical novae T= GK => E Gamow = 100 – 260 keV Resonant Contribution: 17 O(p, γ ) 18 F resonance at E p = 193 keV and non resonant contribution

17 O(p,  ) 18 F measurement State of the art before the LUNA measurement (1): Rolfs et al., 1973, prompt  S DC measured at 4 energies in the range E cm = keV S DC ≈ 9 keV b for E cm = keV Fox et al., 2005, prompt  discovered 193 keV resonance  = (1.2±0.2) eV calculation of DC S DC = E E 2 determination of high energy resonance influence on S total Chafa et al., 2007, activation  = (2.2±0.4) eV measured S DC = (8.3±4.0) keV b S DC = E E 2 larger than Fox by more than 50%

17 O(p,  ) 18 F measurement Status of the art before the LUNA measurement (2): Newton et al., 2010, prompt  S DC measured at 6 energies in the range E cm = keV Calculated S DC (E) = 4.6 keV b (±23%) Hager et al.(DRAGON), 2012, recoil separator E cm = keV S DC higher than Newton and Fox. No flat dependence. Re-evaluate resonant contributions

17 O(p,  ) 18 F measurement The LUNA measurement and results: prompt  and activation at the same time 193 keV resonance with prompt  several unknown transitions discovered correction for summing (close geometry) subtraction of non resonant component  = (1.68±0.13) eV 193 keV resonance with activation subtraction of non resonant component backscattering and contaminants ( 13 N) taken into account  = (1.69±0.03) eV very good agreement between the two results factor ~ 2 higher accuracy than before

17 O(p,  ) 18 F measurement The LUNA measurement and results: DC component E cm = prompt  (both primaries and secondaries) and activation S(E) (keV b) E eff (keV) five-fold reduction in reaction rate uncertainty!

reactionQ-value (MeV) 17 O(p,  ) 18 F 17 O(p,  ) 14 N O(p,  ) 19 F 18 O(p,  ) 15 N Na(p,  ) 24 Mg Ne(p,  ) 23 Na8.8 D( ,  ) 6 Li1.47 just started LUNA 400 kV program Still three reactions to be measured+ 2 just started  LUNA 3 needs a prolongation of 2 years: 2013 and 2014 just started completed

LUNA MV Project April 2007: a Letter of Intent (LoI) was presented to the LNGS Scientific Committee (SC) containing key reactions of the He burning and neutron sources for the s-process: 12 C( ,  ) 16 O 13 C( ,n) 16 O 22 Ne( ,n) 25 Mg ( ,  ) reactions on 14,15 N and 18 O These reactions are relevant at higher temperatures (larger energies) than reactions belonging to the hydrogen- burning studied so far at LUNA Higher energy machine  3.5 MV single ended positive ion accelerator

Possible location at the "B node" of a 3.5 MV single-ended positive ion accelerator

In a very low background environment such as LNGS, it is mandatory not to increase the neutron flux above its average value Study of the LUNA-MV neutron shielding by Monte Carlo simulations α beam intensity: 200 µA Target: 13 C, at/cm 2 (99% 13 C enriched) Beam energy(lab) ≤ 0.8 MeV α beam intensity: 200 µA Target: 22 Ne, at/cm 2 Beam energy(lab) ≤ 1.0 MeV from α beam intensity: 200 µA Target: 13 C, at/cm 2 ( 13 C/ 12 C = ) Beam energy(lab) ≤ 3.5 MeV Maximum neutron production rate : 2000 n/s Maximum neutron energy (lab) : 5.6 MeV

Simulations A document describing the final solutions for the shielding against neutrons of the B-node equipped with a 3.5 MeV accelerator has been approved by the "neutron committee" (Hass, Esposito, Kutschera,, Lembo, Terrani) and by the LNGS Scientific Committee This documents contains the results of the GEANT4 simulations (50 million events for the "gas target" and 50 million events for the "solid target") Minimum detectable flux: n cm -2 s -1

Shielding layout Point like, isotropically emitting neutron source: R= 2000 n/s E=5.6 MeV monochromatic

Results C region (gas target)

LUNA-MV Funding Special project "Progetto Premiale" Request: 2.8 Meuro for Total request: 6.4 Meuro in 5 years RECENTLY APPROVED FOR 2012

Progetto Premiale LUNA MV (1)

Progetto Premiale LUNA MV (2)

Progetto Premiale LUNA MV (3)

LUNA-MV Permissions Local authorities permissions: A technical document has been prepared (in Italian) to be used for discussion with local authorities. February 2 nd : meeting with Teramo aqueduct  very positive February 28 th : meeting with the Teramo Health Institute (ASL Teramo)  few issues Technical specifications of all materials which will be used for the site preparation ; technical characteristics of the accelerator + shielding sent to "Istituto Superiore di Sanità" at the beginning of May. Visit to the site on June 14 th. Risk matrices to be sent. Official “answer” in about 1 month after the official “question” has been sent.

THE LUNA COLLABORATION Laboratori Nazionali del Gran Sasso A.Formicola, M.Junker Helmoltz-Zentrum Dresden-Rossendorf, Germany M. Anders, D. Bemmerer, Z.Elekes, M.L. Menzel INFN, Padova, Italy C. Broggini, A. Caciolli, R. De Palo, R.Menegazzo, C. Rossi Alvarez INFN, Roma 1, Italy C. Gustavino Institute of Nuclear Research (ATOMKI), Debrecen, Hungary Zs.Fülöp, Gy. Gyurky, E.Somorjai,T. Szucs Osservatorio Astronomico di Collurania, Teramo, and INFN, Napoli, Italy O. Straniero Ruhr-Universität Bochum, Bochum, Germany C.Rolfs, F.Strieder, H.P.Trautvetter Seconda Università di Napoli, Caserta, and INFN, Napoli, Italy F.Terrasi Università di Genova and INFN, Genova, Italy F. Cavanna, P.Corvisiero, P.Prati Università di Milano and INFN, Milano, Italy C. Bruno, A.Guglielmetti, D. Trezzi Università di Napoli ''Federico II'', and INFN, Napoli, Italy A.di Leva, G.Imbriani, V.Roca Università di Torino and INFN, Torino, Italy G.Gervino University of Edinburgh M. Aliotta, T.Davinson, D. Scott

Next-generation underground laboratory for Nuclear Astrophysics Executive summary This document originates from discussions held at the LUNA MV Roundtable Meeting that took place at Gran Sasso on February It serves as a call to the European Nuclear Astrophysics community for a wider collaboration in support of the next-generation underground laboratory. To state your interest to contribute to any of the Work Packages, please add your name, contact details, and WP number under International Collaboration. WP1: Accelerator + ion source WP2: Gamma detectors WP3: Neutron detectors WP5: Solid targets WP6: Gas target WP7: Simulations WP8: Stellar model calculations

NameInstitutionWork Package(s) Carlos AbiaUniversity of GranadaWP7 Maurizio BussoDept Physics & INFN-PG (Italy)WP7 Gianpiero GervinoINFN TorinoWP3 – WP3 Grigor Alaverdyan Yerevan State University, Radio Physics Faculty, Yerevan 0025, Armenia WP7: Stellar model calculations Pierre Descouvemont Universite Libre de Bruxelles WP7 Sergio CristalloINAF – TeramoWP7 Luciano PiersantiINAF – TeramoWP7 Sean PalingBoulby Mine (UK)No indication Johan Nyberg Uppsala UniversityWP2, WP3, WP6 Yi XuInstitut d’Astronomie et d’Astrophysique, Universite Libre de Bruxelles, 1050, Brussels, Belgium WP6 and WP7 D. Bemmerer et al.HZDRWP5 D. Bemmerer, Z. Elekes et al. HZDRWP6 Andrea LavagnoPolitecnico di TorinoWP7 Lian GangChina Institute of Nuclear Energy WP6 Andreas ZilgesKöln UniversityWP2 Sam Austin NSCL/Mich St Univ WP7 Antonino Di LevaNapoli UniversityWP6 Gianluca ImbrianiNapoli UniversityWP2, WP7 Lucio GialanellaSeconda Università di Napoli and INFN Napoli WP6