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Alpha Cluster Structure in 13 C and 16,17 O

Institute of Physics University of São Paulo. Marcia Regina Dias Rodrigues. Alpha Cluster Structure in 13 C and 16,17 O. Alpha Cluster. Microscopic a cluster model Molecular model a -particle gas like-states.

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Alpha Cluster Structure in 13 C and 16,17 O

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  1. Institute of Physics University of São Paulo Marcia Regina Dias Rodrigues Alpha Cluster Structure in 13C and 16,17O

  2. Alpha Cluster Microscopic a cluster model Molecular model a-particle gas like-states W. von Oertzen, M. Freer, Y. Kanada-En’yo, Physics Reports 432, 43 (2006). K. Ikeda, N. Takigawa, and H. Horiuchi, Prog. Theor. Phys. Suppl. E68, 464 (1968); H. Horiuchi, K. Ikeda, and Y. Suzuki, ibid. 44, 225 (1978). NN2012 - M. R. D. Rodrigues

  3. -cluster phenomenon on light mass nuclei Nuclear Spectroscopy with Light Ions Group Investigation of a-clustering on (xa) and (xa + n) nuclei through (6Li,d) reaction. Scarce experimental information on: • even-even nuclei resonant states near the thresholds. • odd-even nuclei . Odd A nuclei: • 13C(6Li,d)17O and 9Be(6Li,d)13C Even A nuclei: • 12C(6Li,d)16O NN2012 - M. R. D. Rodrigues

  4. Experimental set up • Pelletron-Enge-Spectrograph system • 25.5 MeV6Li beam • Detection: nuclear emulsion(Fuji G6B, 50 μm thick): covering 50 cm along the focal surface. NN2012 - M. R. D. Rodrigues

  5. University of Sao Paulo – campus view Institute of Physics IFUSP-LAFN Pelletron-Enge-Split-Pole-Spectograph facility NN2012 - M. R. D. Rodrigues

  6. Pelletron-Enge-Split-Pole-Spectograph facility Tandem 9MV NN2012 - M. R. D. Rodrigues

  7. Pelletron-Enge-Split-Pole-Spectograph facility NN2012 - M. R. D. Rodrigues

  8. Nuclear emulsion plates No magnification (three spectra on each emulsion plate) View under 500x magnification (120x110m2) NN2012 - M. R. D. Rodrigues

  9. Data • Plates were scanned in strips of 200μm. • Absolute cross section through elastic scattering of 6Lion the same target. NN2012 - M. R. D. Rodrigues

  10. 13C(6Li,d)17O α threshold preliminary NN2012 - M. R. D. Rodrigues

  11. NN2012 - M. R. D. Rodrigues

  12. 9Be(6Li,d)13C ELi = 25.5 MeV , qLab= 5o NN2012 - M. R. D. Rodrigues

  13. 9Be(6Li,d)13C ELi = 25.5 MeV , qLab= 5o NN2012 - M. R. D. Rodrigues

  14. NN2012 - M. R. D. Rodrigues

  15. Preliminary Analysis • One step atransfer finite-range DWBA calculations. • Optical model in entrance and exit channels: global parameters of Cook and Daehnick et al. • Binding potential (a+d) of Kubo and Hirata. • Resonant states assumed abound by 100 keV in WS potential (r0 = 1.25 fm, a = 0.65 fm). Relative to 9Be core for negative (G=4) and positive (G=5) parity a states were considered J. Cook, Nucl. Phys. A388, 153 (1982) W.W. Daehnick, J.D. Childs and Z. Vrcelj, Phys. Rev. C 21, 2253 (1980)K.I. Kubo and M. Hirata, Nucl. Phys. A187, 186 (1972) NN2012 - M. R. D. Rodrigues

  16. Resonance at 12.3 MeV, consistent with an L = 2 transfer, in agreement with 1/2- attribution of Kawabata - Strongly excited by (a,a’), present a large E0 transition. Resonances 7/2- at 10.753MeV and (5/2-) at 10.818MeV are now resolved and reached by an L = 4 transfer Resonances 7/2-is also described using in the DWBA form factor the wave function obtained by a simplified calculation of the a+9Be system. Local cluster – core potential, B. Buck, A.C.Merchant and S.M. Perez Phys. Rev. C51, 559 (1995) H. Miyake and M.A. Souza - IFUSP a+ 9Be 13C (inert core G.S.) NN2012 - M. R. D. Rodrigues

  17. 12C(6Li,d)16O ELi = 25.5 MeV Position deuteron spectrum and corresponding scattering angle. The Jp and excitation energies in MeV associated with each state from D. R. Tilley et al., Nucl. Phys. A 565 , 1-184 (1993)are indicated. NN2012 - M. R. D. Rodrigues

  18. 12C(6Li,d)16O reactionat 48.2MeVby A. Belhout et al., Nucl. Phys. A793, 178 (2007) Position deuteron spectrum. Indicated is the region of the 4a threshold. NN2012 - M. R. D. Rodrigues

  19. 12C(6Li,d)16O reactionat 42 MeVby C. Weldonet al. Q3D deuteron spectrum at -21.5º Q3D deuteron spectrum at -21.5º gated to select states decaying to the 12C ground state. Q3D deuteron spectrum at -21.5º gated to select states decaying to the 12C 21+ state at 4.439 MeV. C. Wheldon et al., Phys. Rev. C 83, 064324 (2011). NN2012 - M. R. D. Rodrigues

  20. Elastic angular distribution and optical model predictions. The fitted parameters are rR = 1.70 fm and aR =0.66 fm. NN2012 - M. R. D. Rodrigues

  21. L. L. Ames et al., Phys. Rev. C 25,729 (1982) 16O resonances in 12C(a,a0)12C (g.s.) excitation function. States with natural parities and indicated before as a direct process. • Experimental angular distributions not previously reported. NN2012 - M. R. D. Rodrigues

  22. NN2012 - M. R. D. Rodrigues

  23. C. Wheldon et al., Phys. Rev. C 83, 064324 (2011) 2- 4(-) 5+ Ressonances decaying to 12C 21+ state. 2- • Experimental angular distributions not previously reported. NN2012 - M. R. D. Rodrigues

  24. Theoretical rotational band with a + 12C (0+2) cluster structure S. Ohkubo and Y. Hirabayashi, Phys. Lett. B 684,127 (2010). Kp = was not seen Kp = Kp = Experimental alpha rotational bands on 16O. NN2012 - M. R. D. Rodrigues

  25. Next Steps • Obtain detailed angular distributions and complete the analysis of the data. • Pursue the study of a-cluster states populated through 13C(6Li,d)17Oand 11B(6Li,d)15Nreactions. • Extend structure calculation. NN2012 - M. R. D. Rodrigues

  26. Nuclear Spectroscopy with Light Ions, IFUSP, Brasil TherezaBorelloLewin Marcia Regina Dias Rodrigues Hideaki Miyake José Luciano Miranda Duarte LighiaBrighittaHorodynskiMatsushigue Gilberto MitsuoUkita Cleber Lima Rodrigues Marco Antonio de Souza MAGNEX Large-Aceptance Spectrometer, LaboratoriNazionaliSud, INFN, Catania, Italy Angelo Cunsolo, Francesco Cappuzzello Manuela Cavallaro AntoninoFoti ClementinaAgodi Diana Carbone NN2012 - M. R. D. Rodrigues

  27. Thanks Obrigada NN2012 - M. R. D. Rodrigues

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