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Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse

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

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Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse

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

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

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

  4. A. Lefebvre-Schuhl Athens 2009 March 11th Nuclear astrophysics • Central stellar nucleosynthesis: • nuclear reaction predominantly at low energies • in a narrow energy window: Gamow peak • Example: 7Be(p,g)8B (solar interior) • stellar temperature: T = 1.5 x 107 K • 12  E 24 keV •  very low projectile energiesin 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.

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

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

  7. g a cible p b B=3 Teslas A. Lefebvre-Schuhl Athens 2009 March 11th Low energy measurements of the 7Be(p,)8B cross section • 6 bdetectors(plastic scintillators) efficiency: 25 % • 24 a-detectors (Si detectors) 100o < qa < 160o • a efficiency : 11.5 % for 1 MeV < Ea < 3.36 MeV • GEANT simulation of the experiment Cross section measurement for Ec.m. 185.8, 134.7, and 111.7 keV with a radioactive 7Be target (132 mCi) (target thickness: RBS and (d,p)profile analysis) S(0) F. Hammache et al.,Phys. Rev. Lett. 86 (2001) 3985

  8. 17O and 18F nucleosynthesis In hydrogen-burning nucleosynthesis: 17O(p,α)14N and 17O(p,γ)18F reaction rates • 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 Ecm= 183.3 keV in the 17O(p,α)14N reaction  Resonance strength measurement relatively to the Ecm= 150.9 keV 18O(p,α)15N resonance: ωγpa= (1.6 ± 0.2) 10-3 eV  Excitation energy: 5789.8 ± 0.3 keV for the 18F level • Activation method for the 17O(p,γ)18F reaction study • Resonance strength : ωγpγ= (2.2 ± 0.4) 10-6 eV A. Lefebvre-Schuhl Athens 2009 March 11th

  9. A. Lefebvre-Schuhl Athens 2009 March 11th 17O and 18F nucleosynthesis In hydrogen-burning nucleosynthesis: 17O(p,α)14N and 17O(p,γ)18F reaction rates • 17O(p, α)14N rate • now well established below T = 1.5 GK • Uncertainties reduced by orders of magnitude in T= 0.1–0.4 GK • 17O(p,γ)18F rate  Larger uncertainty because of remaining obscurities in the knowledge of the direct capture process Important consequences for 17O nucleosynthesis and γ-ray emission of classical novae A. Chafa et al. Phys. Rev. Lett. 95 (2005) 031101 A. Chafa et al. Phys. Rev. C75 (2007) 035810

  10. A. Lefebvre-Schuhl Athens 2009 March 11th 19F(p,a)16O13C(a,n)16O  a beam • 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

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