Nuclear structure and fundamental interactions Solid state physics Material irradiation Micrometeorite research and study Astrophysics Nuclear astrophysics Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse A. Lefebvre-Schuhl Athens 2009 March 11 th

JANNuS Implantation with 2 ions beams Thin targets characterization In situ observation with the TEMSEMIRAMIS A. Lefebvre-Schuhl Athens 2009 March 11 th Joint Accelerators for Nano-sciences and Nuclear Simulation Ion beam analysis + channeling Irradiation & implantation Tandem 2 MV 190 kV 200 kV Y. Serruys et al. Nucl. Instr. and Meth. B240 (2005) 124

detection 135° Doubly Focusing Magnet Electromagnetic isotope separator Direct isotope collection Preparation of thin targetsSIDONIE A. Lefebvre-Schuhl Athens 2009 March 11 th

Central stellar nucleosynthesis: nuclear reaction predominantly at low energies in a narrow energy window: Gamow peak Example: 7 Be(p,  ) 8 B (solar interior) stellar temperature: T = 1.5 x 10 7 K 12  E  24 keV  very low projectile energies in the laboratory Charged particle induced nuclear reactions  Coulomb barrier Very low energies  very low cross sections (~1 nb) high ion beam currents (up to 1mA) and high detection efficiency for the reaction products. A. Lefebvre-Schuhl Athens 2009 March 11 th Nuclear astrophysics

PAPAP PAPAP P etit A ccélérateur P our l’A stro P hysique G. Bogaert et al. Nucl. Instr. and Meth. B89 (1994) 8 A. Lefebvre-Schuhl Athens 2009 March 11 th 250 kV proton accelerator for applications in nuclear astrophysics high proton beam currents in the range of 0.5 mA

 coupling with a superconducting solenoidal spectrometer SOLENO for studies of particle emitting reactions SOLENO Requirements: high detection efficiency scattered protons and emitted  -particles separation Henri THUREL A. Lefebvre-Schuhl Athens 2009 March 11 th

F. Hammache et al.,Phys. Rev. Lett. 86 (2001) 3985    p cible B=3 Teslas Low energy measurements of the 7 Be(p,  ) 8 B cross section  6  detectors (plastic scintillators) efficiency: 25 %  24  -detectors (Si detectors ) 100 o <   < 160 o   efficiency : 11.5 % for 1 MeV < E  < 3.36 MeV  GEANT s imulation of the experiment  Cross section measurement for Ec.m , 134.7, and keV with a radioactive 7 Be target (132 mCi) (target thickness: RBS and (d,p) profile analysis)  S(0) A. Lefebvre-Schuhl Athens 2009 March 11 th

17 O and 18 F nucleosynthesis Various stellar sites such as classical novae Before 2004: very large uncertainties on the thermonuclear rates of these two reactions in the temperature range of classical novae (T = 0.01–0.4 GK) New resonance at E cm = keV in the 17 O(p,α) 14 N reaction  Resonance strength measurement relatively to the E cm = keV 18 O(p,α) 15 N resonance: ωγ p  = (1.6 ± 0.2) eV  Excitation energy: ± 0.3 keV for the 18 F level Activation method for the 17 O(p,γ) 18 F reaction study  Resonance strength : ωγ pγ = (2.2 ± 0.4) eV In hydrogen-burning nucleosynthesis: 17 O(p,α) 14 N and 17 O(p,γ) 18 F reaction rates A. Lefebvre-Schuhl Athens 2009 March 11 th

17 O and 18 F nucleosynthesis 17 O(p, α) 14 N rate  now well established below T = 1.5 GK  Uncertainties reduced by orders of magnitude in T= 0.1–0.4 GK 17 O(p,γ) 18 F rate  Larger uncertainty because of remaining obscurities in the knowledge of the direct capture process Important consequences for 17 O nucleosynthesis and γ-ray emission of classical novae In hydrogen-burning nucleosynthesis: 17 O(p,α) 14 N and 17 O(p,γ) 18 F reaction rates A. Chafa et al. Phys. Rev. Lett. 95 (2005) A. Chafa et al. Phys. Rev. C75 (2007) A. Lefebvre-Schuhl Athens 2009 March 11 th

Target study –stability under high beam currents –purity vs unwanted induced reactions Detection study : –expected cross section –scattered incident particles … Each study is particular and needs time to be succesfull 19 F(p,  ) 16 O 13 C( ,n) 16 O   beam A. Lefebvre-Schuhl Athens 2009 March 11 th