Nuclear Physics in Astrophysics V, Eilat 3-8 April 2011 Hydrogen-burning reactions at astrophysically relevant energies Laboratory Underground Nuclear Astrophysics Alba Formicola
Nuclear Physics in Astrophysics V, Eilat 3-8 April 2011 Outline the main results and achievements in nuclear astrophysics a close look on last LUNA works mainly 3 He( ) 7 Be; 14 N(p, ) 15 O; 15 N(p, ) 16 O (see Caciolli’s poster) 25 Mg(p, ) 26 Al the measurements in progress: d( ) 6 Li (Bellini’s talk) 17 O(p, ) 18 F (see Scott’s poster) perspectives LUNA MV in LNGS (key reactions of the He burning and neutron sources for the s-process)
Nuclear Physics in Astrophysics V, Eilat 3-8 April 2011 Importance of experimental reaction rates for understanding of nucleosynthesis, energy production in stars, solar neutrino problem, theories of stellar evolution Quiescent burning (essentially p and radiative capture): Eo<< CB; < pb i) Direct measurements at E = Eo ii) Extrapolation from higher energy measurements iii) indirect methods (Coul. break-up, delayed activity transfer reactions, "trojan horses") Imply very low background (underground lab) Imply use of efficient and selective detection apparatuses Imply comparison with direct methods and model tuning
reaction S(0) [keV b] Solar Fusion I 1998 S(0) [keV b] Solar Fusion II 2010 p(p,e + e )d (4.01 ± 0.02)* (4.01 ± 0.04)* He( 3 He,2p) 4 He (5.4 ± 0.4)*10 3 (5.21 ± 0.27)* He( ) 7 Be (0.53 ± 0.05)(0.56 ± 0.03) 3 He(p,e + e ) 4 He 2.3* (8.6 ± 2.6)* Be(p, ) 8 B (2.08 ± 0.16)* N(p, ) 15 O ± 0.12 Nuclear Physics in Astrophysics V, Eilat 3-8 April 2011 ( 8 B) ~ (1+ S 11 ) (1+ S 33 ) (1+ S 34 ) 0.85 (1+ S 17 ) 1.0 (1+ S e7 ) -1.0 (1+ S 1,14 ) where fractional uncertainty S 11 S 11 /S 11 (0) (Peña-Garay and Serenelli arXiv: v1) The better determination of cross sections will imply a contribution to the solar abundances understanding (Carlos’ talk) Nuclear reactions in hydrogen-burning
E = 478 keV 3 He( , ) 7 Be(e, ) 7 Li*( ) 7 Li E =1586 keV + E cm (DC 0); E = 1157 keV + E cm (DC 429) E = 429 keV Average prompt Average activa. Prompt Activation The two techniques show a 9% discrepancy Nuclear Physics in Astrophysics V, Eilat 3-8 April 2011
3 He recirculating gas target p=0.7mbar Si-monitor for target density measurements (beam heating effect) Collimated HPGe detector to collect ray at 55 0.3 m 3 Pb-Cu shield suppression five orders of magnitude below 2MeV Removable calorimeter cap for offline 7 Be counting Experimental set-up GOAL at LUNA reach an accuracy ~ 4-5 % Nuclear Physics in Astrophysics V, Eilat 3-8 April 2011
LUNA spectra: via detection of prompt and delayed rays Confortola et al., PRC 75, (2007) Nuclear Physics in Astrophysics V, Eilat 3-8 April 2011 Gyurky et al., PRC 75, (2007)
Extrapolation to solar energies: 3 He( ) 7 Be Potential models (global scaling parameter): Tombrello & Parker, Descouvemont (R-matrix based), Mohr Microscopic models (no global scaling parameter): Csótó & Langanke, Kajino et al., Nollett, etc... Usually claimed to be valid up to E cm ~2.0MeV By Courtesy of A. Di Leva (ERNA collaboration) Nuclear Physics in Astrophysics V, Eilat 3-8 April 2011
S 34 (0)= 0.56 ± 0.02 (exp) ± 0.02 (model) keV b ref: Solar fusion cross sections II: arXiv: v3 (The analysis is based on all activation data plus ERNA recoil data) Further work … By Courtesy of C. Peña-Garay Improved models are needed to assess the low energy slope of S 34 (E) (see also talk by Neff) Additional experimental information to better constrain the models will help to reduce the uncertainty ( see also talk by Bondili and Carmona ‘s poster) Nuclear Physics in Astrophysics V, Eilat 3-8 April 2011 The 3 He( ) 7 Be reaction: S(0)
Transition(MeV) Schröder et al. (Nucl.Phys.A 1987) Angulo et al. Angulo et al. (Nucl.Phys.A 2001) RC / ± ± 0.06 RC / ± ± 0.02 RC / ± ± 0.17 S(0) [kev-b] 3.20 ± ± 0.20 The 14 N(p, ) 15 O reaction before LUNA and LENA works Sch. Angulo Nuclear Physics in Astrophysics V, Eilat 3-8 April 2011
High resolution measurement (2004) Solid target + HPGe detector Measurement of all γ transitions Energy range keV summing had to be considered R-matrix on single transitions Nuclear Physics in Astrophysics V, Eilat 3-8 April 2011 Gas target+ BGO detector BGO detector efficiency in the ROI ~ 65% measurement of total cross section Energy range keV R-matrix solid target in agreement with data High efficiency measurement (2006) CNO neutrino flux decreases a factor 2 Globular Cluster age increases of 0.7 – 1 Gyr
New precision study of Ground State Clover (2008) E = 318, 324, 353 keV, Solid TiN thick+ Clover detector: 4 single HPGe crystals closely packed: Surrounding BGO for anti-Compton shielding Measurement of the RC → 0 transition Negligible summing correction Nuclear Physics in Astrophysics V, Eilat 3-8 April 2011 Direct Meaus. Indirect Measu. Ex [keV] Schöreder et al. NuPhA467 (1987) LUNA EPJ25 (2005) LENA PRL94 (2005) Mukhamedzhanov et al. PRC 67(2005) Nelson et al PRC 67 (2003) ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± 0.20 tot3.20 ± ± ± ± 0.22 The 14 N(p, ) 15 O reaction: S(0)
Typical clover -spectra E p =290keV 19 F(p, ) 16 O DC → → → → → 0 DC → 6792 DC → 6172DC → 5181 E p =380keV Nuclear Physics in Astrophysics V, Eilat 3-8 April 2011
Results for capture to ground state 14 N(p, ) 15 O At three energies, precise ratio of cross sections: ground state / 6792 Updated R-matrix fit, new recommended S GS (0)=0.20±0.05 keV barn LUNA (2004): 0.25 0.06 keV barn TUNL (2005): 0.49 0.08 keV barn LUNA (2008): 0.20 0.05 keV barn Marta et al., Phys.Rev.C 78, (R) (2008) Marta et al. arXiv: v1 (accpted PRC 2011)arXiv: v1 Nuclear Physics in Astrophysics V, Eilat 3-8 April 2011
R-matrix fit to the 14 N(p, ) 15 O 6.79 MeV transition S 14 (0) = 1.66 ± 0.12 keV b ref: Solar fusion cross sections II: arXiv: v3 Further work on 14 N(p, ) 15 O is needed A better understanding of the reaction mechanism to the 6.79 MeV state at high energies. Additional experimental and theoretical work on the transition to the 6.17 MeV state is needed Nuclear Physics in Astrophysics V, Eilat 3-8 April 2011
AGB nucleosynthesis - 17 O/ 18 O abundaces, 19 F origin, 26 Mg excess....: ………………….., 15 N(p, ) 16 O, 15 N(p, ) 12 C, 17 O(p, ) 18 F( + ) 18 O, 18 O( ) 22 Ne, ………, 24 Mg(p, ) 25 Al( + ) 25 Mg, 25 Mg(p, ) 26 Al( + ) 26 Mg, 26 Mg(p, ) 27 Al… H-shell burning
Nuclear Physics in Astrophysics V, Eilat 3-8 April Q Al 0 26 Al m (4 + ) Al Novae explosive Burning (T 9 >0.1) AGB or W-R Stars (T 9 ~0.05) E x (keV) JJ E CM (keV) No direct strength resonance data Mg CIRCE lab. Caserta, Italy Complementary study of 25 Mg(p, ) 26 Al( + ) 26 Mg HPGe phase E cm =304,190 keV AMS E cm =304keV BGO phase E cm =304,190,93 keV
Nuclear Physics in Astrophysics V, Eilat 3-8 April Mg(p, ) 26 Al spectrum at E cm = 190 keV Branchngs EE EXEX LUNA [%] err Endt [%] O(p, ) 19 F 11 B(p, ) 12 C 19 F(p, ) 16 O 11 B(p, ) 12 C
25 Mg(p, ) 26 Al E cm = 190 keV wg [eV] LUNA HPGe wg [eV] LUNA BGO wg [eV] Iliadis et al wg [eV] NACRE wg [eV] AMS Arazi et al 2006 (8.8±0.8)x10 -7 (9.2 ±0.7) (7.1 ± 1.0) (7.1 ± 0.9) (1.5 ± 0.3) Mg(p, ) 26 Al E cm = 304 keV wg [meV] LUNA HPGe wg [meV] LUNA BGO wg AMS / wg BGO LUNA AMS wg [meV] Iliadis et al wg [meV] NACRE 30.7 ± ± ± ± 231 ± 2 Results Preliminary to be published B. Limata, et al., PRC 82(2010) -ray signal intrinsic background beam induced background level of cosmic-ray background in surface lab 25 Mg(p, ) 26 Al spectrum E R = 93 keV
Nuclear Physics in Astrophysics V, Eilat 3-8 April 2011 New study of the 17 O(p, ) 18 F and 17 O(p, ) 14 N 17 O+p is of paramount importance for understanding hydrogen-burning in different stellar environments: Red Giants Massive Stars Asymptotic Giant Branch (AGB) Varying the corresponding 17 O(p, ) 14 N and 17 O(p, ) 18 F reaction rates within the adopted uncertainty intervals, the isotopic abundances of 17 O and 18 F change by more than a factor 2 in Nova nucleosynthesis. C.Fox et al PRC71,055801(2005)
Nuclear Physics in Astrophysics V, Eilat 3-8 April 2011 Activation method ( 18 F → 18 O) measured at STELLA (with the collaboration of M.Laubenstein) LUNA approach Resonance and direct capture study with -prompt and activation (Ep= keV) in progress Study of the resonance at E R,lab = 70 keV (alpha channel) using a Double Sided Silicon strip Detector (53cm 2 ) from Edinburgh under backward angles in close geometry High energy study (E R,lab =590 and 716 keV)
Nuclear Physics in Astrophysics V, Eilat 3-8 April O(p, ) 18 F spectrum at E p =300keV DC->3839 DC->3060 DC->937
Nuclear Physics in Astrophysics V, Eilat 3-8 April 2011 The 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 The LUNA collaboration produced an update of the LoI where the experimental conditions and neutron production rates were re-evaluated and the machine chacteristics were better specified. Update on the LUNA MV letter of Intent 42/07 February 26 th, 2010 Alessandra Guglielmetti for the LUNA collaboration LUNA MV LUNA 50kV LUNA 400kV
Nuclear Physics in Astrophysics V, Eilat 3-8 April 2011 Possible location at the interferometric node of a 3.5 MV single-ended positive ion accelerator. A real feasibility study started, the LNGS technical divisions and management are highly involved.
Nuclear Physics in Astrophysics V, Eilat 3-8 April 2011 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
THE LUNA COLLABORATION Laboratori Nazionali del Gran Sasso, INFN, ASSERGI: A.Formicola, C. Gustavino( Universita' di Roma 1), M.Junker, C. Salvo Forschungszentrum Dresden-Rossendorf, Germany M. Anders, D. Bemmerer, Z.Elekes INFN, Padova, Italy C. Broggini, A. Caciolli, R.Menegazzo, C. Rossi Alvarez 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 P.Corvisiero, P.Prati Università di Milano and INFN, Milano, Italy M.Campeggio,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 and D. Scott Nuclear Physics in Astrophysics V, Eilat 3-8 April 2011