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Low energy radioactive beams

Low energy radioactive beams. Recent highlights on nuclear astrophysics and exotic light nuclei at Louvain-la-Neuve. Carmen Angulo, CRC Louvain-la-Neuve, Belgium. FINUPHY meeting Louvain-la-Neuve, Belgium 3-4 May 2004. CYCLONE44. ARES. 18 F(d,p) 19 F. LEDA s. 18 F(p, a ) 15 O.

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Low energy radioactive beams

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  1. Low energy radioactive beams Recent highlights on nuclear astrophysics and exotic light nuclei at Louvain-la-Neuve Carmen Angulo, CRC Louvain-la-Neuve, Belgium FINUPHY meeting Louvain-la-Neuve, Belgium 3-4 May 2004

  2. CYCLONE44 ARES 18F(d,p)19F LEDAs 18F(p,a)15O Novae g-ray emission 7Be+p:charge symmetry and nuclear astrophysics 18F(a,p)21Ne r-process nucleosynthesis 7Be(d,p)8Be Big Bang Nucleosynthesis 14O(a,p)17F: trigger to the rp process New developments 15O(a,a)15O 19Ne(p,g)20Na Hot CNO cycle Unique set-ups New beams: 10C,15O,19NeCYC44 10C+p Study of 11N Unique beams: 6He, 7Be, 18F… 6Heb-delayed a+d emission Study of 5Hand7He

  3. CYCLONE110 CYCLONE30 LEDA beam line CYCLONE44 ARES

  4. The first 19Ne radioactive beam at CYCLONE44 Characterization of ARES and study of the 19Ne(p,g)20Ne reaction Manoël Couder, PhD thesis, June 2004

  5. X-ray bursts novae (p,g) reactions in astrophysics • Important in quiescent burning and in explosive environments such as • Standard technique: g detection…. BUT • Background problems • Difficult determination of total efficiency • Recoil separators for astrophysics research: • ARES (Louvain-la-Neuve), ERNA (Bochum) • DRAGON (TRIUMF)

  6. CYCLONE44 Dipole magnet CH2 Target Wien filter ECR Source Quadrupoles doublet or triplet Detector • Characterization with a 19F stable beam: 19F(p,g)20Ne • Study of 19Ne(p,g)20Na with a 19Ne radioactive beam from CYCLONE44

  7. Experiment Simulation 5.0 4.5 4.0 3.5 3.0 2.5 4 5 6 7 8 9 10 11 Characterization of ARES: 19F(p,g)20Ne M. Couder et al., NIM A 506 (2003)26. • Beam energy distribution • Beam transport : charge state distribution • Product transmission: 20Ne7+ (11.5 ± 0.4) % • Rejection power: (2-5)10-7 Total efficiency 20Ne Counts 19F(p,g)20Ne 19F “leaky” beam Energy (keV)

  8. T=2.0 9 T=1.0 3082 + 0 9 + 2992 1 - 3+/- 2856 T=0.5 ? 9 2643 T=0.2 9 2195 19 2064 Ne+p + 3 - 3 1993 +/- 1841 2 1338 - 2 996 + 1 + 808 4 + 3 606 + 2 0 Na 20 19Ne(p,g)20Na Previous experiments: • Coszach et al. 1994 • Page et al. 1994 • Michotte et al. 1996 • Vancraynest et al. 1998 Theory: • Lamm et al. 1990 • Fortune et al. 2000

  9. Left ROI Right Study of the 448 keV resonance in19Ne(p,g)20Ne with a 19Ne RIB Beam intensity ~ 108 pps (reduced) M. Couder et al., Phys. Rev. C (R) (2004) pile-up Typical spectrum DE (keV) 20Ne reaction product expected RESULTS Upper limit with 90 % C.L.: wg<15.2 meV 19Ne “leaky” beam DE+E(MeV) Several improvements in ARES (to be implemented): • Beam monitoring system • Addition of an analyzing magnet

  10. The new 10C beam at CYCLONE110 Study of the proton drip line nucleus 11N by 10C+p elastic scattering

  11. ? • Width of the 12O ground state: p p 12O 11N 10C 2He 10C Level scheme from: http://www.tunl.duke.edu/nucldata/ The drip line nucleus 11N • Is the charge symmetry (11Be) respected in exotic nuclei? • Excited states in proton rich nuclei Kryger et al. Phys. Rev. Lett. 74 (1995); Phys. Rev. C58, 2568 (1998).

  12. K. Markenroth et al., Phys. Rev. C62 (2000) 034308. V. Guimarães et al., Phys. Rev. C67 (2003) 064601. 14N(3He,6He)11N Spectroscopy of 11N: previous works Experiment at RIKEN: transfer reaction 14N(3He,6He)11N DWBA analysis 10C+p experiment at MSU and GANIL Thick target technique: high energy 10C beam stopped on a gas target

  13. DE - E recoil protons 10C beam target CD/PAD Telescope A dedicated 10C+p experiment to investigate the 11N ground state • Experiment performed end of June 2003 • Goal: study the lower energy states, in particular the 11N ground state using the new 10C beam at the CRC “CD” detector 6 days of running time using: A 10C2+ beam @ 25.5 and 32 MeV, beam intensity ~ 6000 to 10000 pps on target A 1.5 mg/cm2 CH2 target (one expects large resonance widths)

  14. qcm=169.8o qcm=143.6o ds/dW (mb/sr) Ecm (MeV) • Data analysis in the R-matrix framework In order to explain the data 3 resonant states included at c.m. energies 1 to 4 MeV Preliminary Best fit Best fit • Best resolution experiment: resonance energies/widths can be well-established • In fair agreement with other elastic scattering experiments (except for the g.s. energy) • In clear disagreement with the results of a RIKEN experiment: does the transfer reaction method give uncompleted information?

  15. 2004 and beyond…. • Nuclear astrophysics : • 7Be(d,p)8Be for Big Bang Nucleosynthesis (beam time starts on Thursday! ) • 18F(p,a)15O for g-ray emission in novae (after Summer) • 14O(a,p)18Ne for rp-process nucleosynthesis (using CYCLONE44) • … • Development of new beams (14O) • Improvement of the ARES system • Exotic nuclei: • Spins and widths of low-lying states in16F by 15O+p • States of ‘molecular’ characteristics in 10Be by 6He+a • Study of6Be by the 7Be+3He transfer reaction • …

  16. Collaborators • LEDA collaboration (Louvain-la-Neuve and Edinburgh) • PNTPM Brussels • KU Leuven • CSNSM Orsay • LPC Caen • INFN Catania • CSIC Madrid • FLNR Dubna • Kurchatov Institute Moscow • University of York • University of Notre-Dame • University of Birmingham • University of Connecticut • University of Huelva • University of Sevilla • GANIL Caen • CEA Saclay • TRIUMF, Vancouver • Ruder Boskovic Inst., Zagrev

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