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Present and future of

L aboratory. U nderground. N uclear. A strophysics. Present and future of. - Status of the D( a , g ) 6 Li measurement -Status of the 17 O(p, g ) 18 F measurement -Status of the LUNA MV project and plans for the future. Alba Formicola.

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Present and future of

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  1. Laboratory Underground Nuclear Astrophysics Present and future of • -Status of the D(a,g)6Li measurement • -Status of the 17O(p,g)18F measurement • -Status of the LUNA MV project and plans for the future Alba Formicola NuPECC - Milan 9 2012

  2. BBN :Production of the lightest elements (D, 3He, 4He, 7Li, 6Li) in the first minutes after the Big Bang The case of 6Li It has the next-highest predicted primordial abundance after D, 3He, 4He and 7Li It has been found in non negligible quantities in very old low metallicity halo stars unexpectedly high amount (2-3 orders of magnitude compared to available BBN network predictions - NACRE) The primordial abundance is determined by the rate of two reactions: D(a,g)6Li which produces practically all the 6Li 6Li(p,a)3He which destroys 6Li  sufficiently well known Theoretical estimates in the region of interest differ by 1-2 orders of magnitude NuPECC - Milan 9 2012 NuPECC - Milan 9 2012

  3. Experimental set-upto study the D(a,g)6Li reaction D(α,α)D Rutherford scattering also D(D,p)t occurs with similar cross section • monitoring of neutron production D(D,n)3He reaction • 4He beam (I ~300mA) on a windowless • D2 gas target (P=0.3mbar) • beam current measurement by calorimeter • HPGe detector for γ detection Beam induced background NuPECC - Milan 9 2012 NuPECC - Milan 9 2012

  4. Direct measurement of the D(a,g)6L cross section at astrophysical energies (n,n’) reaction on the surrounding materials (Pb, Ge, Cu). -ray background in the D(a,)6Li RoI (~1.6 MeV) The next beam time is scheduled for March and April 2012 • measurement with an AmBe neutron source to compare with simulation results • further work to understand the background in the γ-detector

  5. Astrophysical motivation to study the17O(p,γ)18F reaction Hot-CNO Cycle (p,γ) (p,a) 14N 17O 13C 18F (β+ν) 13N 15N 17F 18O 12C 15N 16O Rolfs et al. Nuc. Phys. A217 29-70 (1973) – Fox et al. Phys. Rev. C 71, 055801 (2005) – 193 keV res. meas. :ωγ193= (1.2±0.2)×10-6eV Chafa et al. Phys. Rev. C 75, 033810 (2007)- Activation meas. : ωγ193= (2.2±0.4)×10-6 eV Newton et al. Phys. Rev. C 81, 045801 (2010): cross section measurements 17O+p is of paramount importance for understanding hydrogen-burning in different stellar environments: • Red Giants • Novae stars • Massive Stars • Asymptotic Giant Branch (AGB)

  6. Experimental setup to study the 17O(p,γ)18F reaction 18O(p,γ)19F target profile Proton energy range covered : 193- 400 keV with an average current I~300 μA Enriched 17O targets Activation and Prompt on Ta backings Gamma measurements NuPECC - Milan 9 2012 NuPECC - Milan 9 2012

  7. On resonance spectra of the 17O(p,γ)18F reaction R -> 1080 R -> 937 Ex(keV) 5789 Ep= 193 keV R -> 2101 17O+p R -> 3133 R -> 3791 3839 937 1080 3791 3358 3134 2523 2101 1080 1041 937 18F NuPECC - Milan 9 2012 NuPECC - Milan 9 2012

  8. The LUNA MV project Higher energy machine 3.5 MV single ended positive ion accelerator 12C(a,g)16O the “Holy Grail” from Nobel Lecture 1993 by William Fowler • Maximum neutron production rate : 2000 n/s • Maximum neutron energy (lab) : 5.6 MeV In a very low background environment such as LNGS, it is mandatory not to increase the neutron flux above its average value from αbeam intensity: 200 µA Target: 13C, 1 1018at/cm2 (13C/12C = 10-5) Beam energy(lab) ≤ 3.5 MeV αbeam intensity: 200 µA Target: 22Ne, 1 1018at/cm2 Beam energy(lab) ≤ 1.0 MeV αbeam intensity: 200 µA Target: 13C, 2 1017at/cm2 (99% 13C enriched) Beam energy(lab) ≤ 0.8 MeV NuPECC- Milan 9 2102

  9. Next-generation underground laboratory for Nuclear Astrophysics: …. 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 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 Representatives: Aliotta Marialuisa, Luis Fraile, Zsolt Fulop, Alessandra Guglielmetti

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