• Nuclear structure and fundamental interactions
• Solid state physics
• Material irradiation
• Micrometeorite research and study
• Astrophysics
• Nuclear astrophysics
Centre de Spectrométrie Nucléaire et Centre de Spectrométrie Nucléaire et de Spectrométrie de Massede Spectrométrie de Masse
A. Lefebvre-Schuhl
Athens 2009 March 11th
JANNuSJANNuS
• Implantation with 2 ions beams
• Thin targets characterization
• In situ observation with the TEM
SEMIRAMISSEMIRAMIS A. Lefebvre-Schuhl
Athens 2009 March 11th
Joint Accelerators for Nano-sciences and Nuclear Simulation
Ion beam analysis + channeling
Irradiation & implantationTandem 2 MV
190 kV200 kV
Y. Serruys et al. Nucl. Instr. and Meth. B240 (2005) 124
detection
135° DoublyFocusing
Magnet
• Electromagnetic isotope separator
• Direct isotope collection
• Preparation of thin targets
SIDONIESIDONIE
A. Lefebvre-Schuhl
Athens 2009 March 11th
Central stellar nucleosynthesis:• nuclear reaction predominantly at low energies• in a narrow energy window: Gamow peak
Example: 7Be(p,)8B (solar interior) • stellar temperature: T = 1.5 x 107 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 11th
Nuclear astrophysicsNuclear astrophysics
PAPAPPAPAPPetit Accélérateur Pour l’AstroPhysique
G. Bogaert et al. Nucl. Instr. and Meth. B89 (1994) 8A. Lefebvre-Schuhl
Athens 2009 March 11th
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
SOLENOSOLENO
Requirements: • high detection efficiency• scattered protons and emitted -particles separation
Henri THUREL
A. Lefebvre-Schuhl
Athens 2009 March 11th
F. Hammache et al.,Phys. Rev. Lett. 86 (2001) 3985
p
cible
B=3 Teslas
Low energy measurements of the Low energy measurements of the 77Be(p,Be(p,))88B B cross sectioncross section
6 detectors (plastic scintillators)
efficiency: 25 %
24 -detectors (Si detectors) 100o < < 160o
efficiency : 11.5 % for 1 MeV < E < 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)
A. Lefebvre-Schuhl
Athens 2009 March 11th
1717O and O and 1818F nucleosynthesisF 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 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:
ωγp= (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
In hydrogen-burning nucleosynthesis: 17O(p,α)14N and 17O(p,γ)18F reaction rates
A. Lefebvre-Schuhl
Athens 2009 March 11th
1717O and O and 1818F nucleosynthesisF nucleosynthesis
• 17O(p, α)14N rate now well established below T = 1.5 GKUncertainties 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
In hydrogen-burning nucleosynthesis: 17O(p,α)14N and 17O(p,γ)18F reaction rates
A. Chafa et al. Phys. Rev. Lett. 95 (2005) 031101A. Chafa et al. Phys. Rev. C75 (2007) 035810
A. Lefebvre-Schuhl
Athens 2009 March 11th
• 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
1919F(p,F(p,))1616OO1313C(C(,n),n)1616O O beam beam
A. Lefebvre-Schuhl
Athens 2009 March 11th
