L’esperimento LUNA- CdS MI giugno 2013 Laboratory Underground Nuclear Astrophysics Alessandra Guglielmetti Università degli Studi di Milano e INFN, Milano, ITALY L’esperimento LUNA: misure recenti Stato del Progetto Premiale LUNA MV Alessandra Guglielmetti & Davide Trezzi (assegnista INFN fino a gennaio 2013 e assegnista UNIMI da aprile 2013) + laureandi M. Campeggio, C. Bruno

Hydrogen burning 4p  4He + 2e+ + 2e + 26.73 MeV pp chain p + p  d + e+ + ne d + p  3He + g 3He +3He  a + 2p 3He +4He  7Be + g 7Be+e- 7Li + g +ne 7Be + p  8B + g 7Li + p  a + a 8B 2a + e++ ne 84.7 % 13.8 % 13.78 % 0.02 % pp chain

BBN reaction network Be Li He p D H n 1. n  p + e- + n p + n  D + g 3 4 Be 7 Li H D p n 2 1 8 9 6 11 12 10 5 13 1. n  p + e- + n p + n  D + g D + p  3He + g D + D  3He + n D + D  3H + p 3H + D  4He + n 3H + 4H  7Li + g 3He + n  3H + p 3He + D  4He + p 3He + 4He  7Be + g 7Li + p  4He + 4He 7Be + n  7Li + p 4He + D  6Li + g

17O(p,g)18F measurement Campeggio 17O+p is very important for hydrogen burning in different stellar environments: - Red giants - Massive stars - AGB - Novae production of light nuclei (17O/18O abundances....); observation of 18F g-ray signal (annihilation 511 keV). Classical novae T=0.1-0.4 GK => EGamow = 100 – 260 keV Resonant Contribution: 17O(p,γ)18F resonance at Ep = 183 keV and non resonant contribution

17O(p,γ)18F experimental setup Proton energy range : E=185- 400 keV average current I~300 μA NuPECC - Milan 9 2012 NuPECC - Milan 9 2012 Nuclear Astrophysics at LSC 5

17O(p,g)18F measurement 183 keV resonance: wg=1.67±0.12 meV (weighted average of prompt and activation) Several new transitions identified and branching ratios determined

17O(p,g)18F results A. Caciolli et al., Eur. Phys. J. A (2012) 48:144 D. Scott et al., Phys. Rev. Lett. 109 (2012) 202501 (Editors' suggestion) A Di Leva et al., to be submitted to Phys. Rev C. Best fit of available data Improvement of a factor of 4 in the reaction rate uncertainty!

BBN reaction network Be Li He p D H n 1. n  p + e- + n p + n  D + g 3 4 Be 7 Li H D p n 2 1 8 9 6 11 12 10 5 13 1. n  p + e- + n p + n  D + g D + p  3He + g D + D  3He + n D + D  3H + p 3H + D  4He + n 3H + 4H  7Li + g 3He + n  3H + p 3He + D  4He + p 3He + 4He  7Be + g 7Li + p  4He + 4He 7Be + n  7Li + p 4He + D  6Li + g

The 6Li case BBN prediction 7Li 6Li BBN prediction 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 6Li) The primordial abundance is determined by: 2H(a,g)6Li producing almost all the 6Li 6Li(p,a)3He destroying 6Li  well known At LUNA direct measurements at the energies of astrophysical interest BBN prediction 7Li 6Li BBN prediction

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

Experimental set-up M. Anders et al., EPJA (2013) 49:28 Reduced gas volume: pipe to minimize the path of scattered 2H and hence diminish the d(d,n)3He reaction yield HPGe detector in close geometry: larger detection efficiency and improved signal-to-noise ratio M. Anders et al., EPJA (2013) 49:28

2H(a,g)6Li analysis Trezzi Two measurement campaigns: a) 400 keV and 280 keV b) 360 keV and 240 keV at 400 keV the expected S/N ratio is about 1/12 Signal: Eg = Q + ECM - DErec± DEDoppler 400 (360) keV and 280 (240) keV ROIs not overlapping Background almost independent on beam energy A counting excess is clearly visible both at 400 and 360 keV! Possible systematics still under evaluation

17O(p,α)14N measurement C. Bruno Never measured AGB stars ( T=0.03-0.1 GK ) Classical Novae ( T=0.1-0.4 GK ) rare isotopes production Q= 1.2 MeV

17O(p,α)14N – experimental setup Beam entrance 8 silicon detectors Al+Mylar (2 μm) To stop scattered protons Test resonance 18O(p,a)15N E=151 keV solid Ta2O5 target (not visible). 17O enriched

17O(p,α)14N – 193 keV resonance Very preliminary: <100mC of collected charge I<10mA A signal is visible on all working detectors Roughly 20% below literature Deeper investigation needed #3 #4 #5 #6 #7

Publications A. Caciolli et al., "Preparation and characterization of isotopically enriched Ta2O5 targets for nuclear astrophysics studies" Eur. Phys. J. A (2012) 48:144 D. Scott et al., "First direct measurement of the 17O(p,g)18F reaction cross-section at Gamow energies for classical novae" Phys. Rev. Lett. 109 (2012) 208001 O. Straniero et al., "Impact of a revised 25Mg(p,g)26Al reaction rate on the operation of the Mg-Al cycle” APJ (2013) 763:100 M. Anders et al., "Neutron-induced background by an alpha-beam incident on a deuterium gas target and its implications for the study of the 2H(a,g)6Li reaction at LUNA" Eur. Phys. J. A (2013) 49:28 A. Di Leva et al., "Underground measurement of 17O(p,g)18F for explosive H burning" to be submitted to PRC

The Premium Project LUNA MV submitted to the Italian Research Ministry Year 1 Year 2 Year 3 Year 4 Year 5 Preparation of the site at LNGS (structures, plants, radiation shielding, safety systems). Definition of the technical parameters of the ion accelerator, start of the tender and issue of the supply order Design of beam lines for solid and gaseous targets . Purchase and construction of needed equipment and materials Design of detectors and data acquisition systems.   Purchase and construction of the required hardware and software. Installation of the ion accelerator. Construction of the beam lines. Development of detection and data acquisition systems Set-up and calibration of the accelerator, beam lines, detectors. Running of test experiments. First experiment at the gas target beam line (measurement of the cross section of the 3He(a,γ)7Be reaction over a wide energy range). First experiment at the solid target beam line (determination of the contamination of titanium nanoparticles)

SUBMITTED! FINANCED! Year 1 Year 2 Year 3 Year 4 Year 5 Site preparation (505)   Ion accelerator (2000) Shielding (300) accelerator beam line (750) beam line to the gas target (320) solid target (255) γ ray detectors (450) charged particle detectors (50) electronics and data acquisition (150) mobility (120) general expenses (450) Post Docs (150) PHDs (247,5) Mobility (120) Research grants (50) Research grants (50) Tot = 2805 2942,5 170 120 Year 1 Year 2 Year 3 Year 4 Year 5 Site preparation (505)   Ion accelerator (2000) Shielding (300) accelerator beam line (750) beam line to the gas target (320) solid target (255) γ ray detectors (450) charged particle detectors (50) electronics and data acquisition (150) mobility (120) general expenses (450) Post Docs (150) PHDs (247,5) Mobility (120) Research grants (50) Research grants (50) Tot = 2805 2942,5 170 120 SUBMITTED! FINANCED!

LUNA MV recent activities (1) 3D laser scanner profile of the B node Removal of interferometer Technical Design Report Technical Document for Health Institute (ISS) Time schedule until 2015/2016 Project of a new shielding solution (cheaper and more technically feasible)

LUNA-MV Permissions The B-node rock walls contain water utilities of the Teramo aqueduct In 2012: a few meetings of the LUNA collaboration, LNGS management and LNGS technical division with the Teramo aqueduct,Teramo Health Institute (ASL Teramo) and "Istituto Superiore di Sanità" (main Health Institute) A document containing: a full description of the B-node site, of the LUNA MV accelerator and shielding, of the works necessary for the preparation of the site including technical specifications of all the materials which will be used, and the risk matrices sent to "Istituto Superiore di Sanità" on Feb 11th, 2013 for an official answer to the question if the LUNA MV project and site preparation have an impact on the water quality The expected (positive) answer will be sent also to Teramo Health Institute and Abruzzo Region The works for the site preparation will start

Shielding Trezzi

LUNA MV recent activities (2) Once the ISS answer will arrive we are ready with the technical documentation needed to start 4 tenders: -Accelerator -Site preparation -HDPE (5%B) panels -Boron Carbide to be inserted in the concrete for the shielding Moreover: Main characteristics of the electrical and safety plants have been defined. Cost definition is still on going Feasibility to bring in the accelerator has been verified

Workshop 60 participants mainly from Europe but also Asia and USA So far: France: Marseille+Orsay+Ganil Poland:Szczecin USA:University of Connecticut Korea: to be better defined + single scientists 60 participants mainly from Europe but also Asia and USA Status of LUNA MV Physics cases with round table on specific technical aspects Discussion on the collaboration structure Request for adhesions "adhesion should be intended as the willingness of the involved group to apply soon to the financing agency of the respective country...."