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Carlo Broggini, INFN-Padova

LUNA beyond the Sun. Carlo Broggini, INFN-Padova. Men in pits or wells sometimes see the stars…. Aristotle. Nuclear Burning in Stars s (E star ). s ( E ) = S(E) e –2 ph E -1. . Reaction Rate(star) . F (E) s (E) dE. Extrap. Meas. Gamow Peak. s. Maxwell Boltzmann. s.

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Carlo Broggini, INFN-Padova

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  1. 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–2phE-1  Reaction Rate(star)  F(E) s(E) dE Extrap. Meas. Gamow Peak s Maxwell Boltzmann s

  2. F Fn = 0.7m-2 h-1 310-6cm-2 s-1 luna

  3. LUNA1 ( 50kV) LUNA2 (400kV) 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 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

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

  5. 278 7556 1/2+ 7297 7276 7/2 + 14N+p 6859 5/2 + -21 6793 3/2 + - 504 6176 3/2 - 14N(p,g)15O 5241 5/2 + 5183 1/2 + Q=7.3 MeV 15O 0 1/2 -

  6. Motivation • Nucleosintesis of the elements 24<A<27 • Astronomical interest of 1809 keV 26Mg line 25Mg(p,g)26Al J Ex (keV) ECM (keV) 5+ 304 6598 5+ Novae explosive Burning (T9>0.1) 190 6496 130 6436 4- AGB or W-R Stars (T9~0.05) 92 6399 2- 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. 228 0+ 26Alm 0 5+ 26Al0

  7. What else can be done with LUNA II (400kV) ? CNO Ne-Na BBN proposal submitted to INFN (2008-2012)

  8. 2H(,g)6Li Burning energy: 50-300 keV Q=1.47 MeV

  9. 12C(a,g)16O • MV-accelerator • 12C-enriched targets • Beam intensity: 500mA • 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

  10. Reactions powering the astrophysical s-process • 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

  11. 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

  12. 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

  13. 3He(,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 %

  14. 0.53 ± 0.05 keV b (9%) [Adelberger 98] 0.54 ± 0.09 keV b (16%) [NACRE 99] Recommended S34(0)values: R-matrix analysis: 0.51 ± 0.04 keV b (8%) [Descouvemont 2004] Summary of previous measurements <S34(0)> = 0.51 ± 0.02 keV b <S34(0)> = 0.57 ± 0.03 keV b

  15. Activation measurement • 4He beam @ 350 keV • <I> ~ 230 µA • Recirculated 3He @ 0.7 mbar T½ =52.2±1.5 d

  16. Prompt -spectra • 4He beam @ 400 keV • <I> ~ 300 µA • Irradiation time: 4.4d • 4He beam @ 220 keV • <I> ~ 240 µA • Irradiation time: 24.4d

  17. ΔS = -1.4  4.2 %

  18. S34(0) = 0.560  0.017 keV barn

  19. s of3He(,g)7Be down to 93keV • 7Be ≈ prompt g • S34(0) = 0.560  0.016 keV barn • ΔΦ(B) reduced from 12% to 10% • ΔΦ(Be) reduced from 9.4% to 5.5% • (C. Pena Garay)

  20. 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, Ruhr-Universität Bochum (GE) •Atomki Debrecen (Hungary)

  21. HPGe Efficiency Efficienza %

  22. ACTIVITY PROMPT-

  23. 25Mg(p,g)26Al Q=6.3 MeV • Nucleosynthesis Mg-Al • Astronomical interest of the from • 26Al decay • Cross section at 180-400 keV with Ge detectors • Cross section down to 90 keV with BGO summing crystals

  24. Target incl LN2 Trap and H2O cooling LN2 Trap (Isolated) Beam Profile Monitor Lead shielding Faraday Cup Gate Valve Wobblers Bellow 4 Slits 1”x1”NaI(Tl) 4 BGO Detector Turbo Pump

  25. * cno from the Sun * Globular cluster age * C yield in AGB stars

  26. 15N(p,g)16O Q=12.13 MeV

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