Elsevier

Nuclear Physics

Volume 61, Issue 4, January 1965, Pages 625-640
Nuclear Physics

The alpha-particle breakup of the 12.71 and 11.83 MeV levels in C12

https://doi.org/10.1016/0029-5582(65)90612-7Get rights and content

Abstract

The alpha-particle decay of states in C12, with special emphasis on those at 11.83 and 12.71 MeV excitation, has been studied using the B11(d, n)C12 reaction. Neutron time-of-flight spectra and semiconductor detector charged-particle spectra were analysed by a two-parameter pulse-height analyser. Angular and energy distributions of the alpha particles from the 12.71 and 11.83 MeV states indicate that these states decay sequentially through Be8. The 1+ spin-parity assignment for the 12.71 MeV state is supported by the fact that no transitions to the ground state of Be8 were observed. Approximately 90% of the transitions from the 11.83 MeV state proceed via Be8(2.9 MeV) while the remaining 10% feed the ground state. There is some evidence to indicate that the 10.84 MeV state of C12 decays exclusively to Be8(0). The 3 assignment for the 9.64 MeV state in C12 is favoured over 1 on the basis of the angular distribution of the alpha particles from this state to the Be8 ground state.

This work, together with other reported in the literature, justifies the representation of C12 as a Be8+α two-body cluster from the alpha-particle threshold to 16 MeV excitation. Such a representation is in accordance with the two-body cluster model of Phillips and Tombrello.

References (26)

  • K. Wildermuth et al.

    Nuclear Physics

    (1958)
  • G.C. Phillips et al.

    Nuclear Physics

    (1960)
  • T.A. Tombrello et al.

    Nuclear Physics

    (1960)
  • J.T. Sample et al.

    Bull. Am. Phys. Soc.

    (1962)
  • T.D. Newton
  • J.D. Jackson et al.

    Phys. Rev.

    (1953)
  • E.H. Beckner et al.

    Phys. Rev.

    (1961)
  • R.K. Sheline et al.

    Nuclear Physics

    (1960)
  • E.P. Wigner et al.

    Phys. Rev.

    (1947)
  • Miller et al.

    Phys. Rev.

    (1954)
    Miller et al.

    Phys. Rev.

    (1955)
  • R.D. Bent et al.

    Phys. Rev.

    (1955)
  • C.W. Cook et al.

    Phys. Rev.

    (1957)
  • P.J. Dee et al.
  • Cited by (0)

    Work supported in part by the Atomic Energy Control Board of Canada.

    View full text