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James D. King

King James


Experimental nuclear physics; nuclear astrophysics.

  • Telephone: (416)978-2959
  • e-mail: king@physicsdomain

Brief CV

B.A., Toronto (1956); Ph.D., Saskatchewan (1960). NRC Postdoctoral Fellow, McMaster (1960-61); Visiting Scientist, S.I.N., Zurich (1969-70); Visiting Scientist, Oxford (1976-77); Visiting Research Fellow, Melbourne (1984-85); Associate Dean and Registrar, Scarborough College (1971-74); Associate Dean (Academic), Scarborough College (1975-76, 1980-81).

Research Interests

Most of the nuclear reactions of importance in explosive nucleosynthesis of light nuclei (A < 41) involve the interaction of protons or alpha particles with unstable nuclei. A project (ISAC-1) is underway at TRIUMF to produce large quantities of selected radioactive species with a view to subsequently accelerating them and bombarding targets of hydrogen or helium. A target-ion source test facility (TISOL) has been constructed to test some of the target materials and ion sources needed for such a facility. TISOL can also be used to provide information on the properties of selected nuclear states (such as the 9.59 MeV 1- state in 16O) which are of great astrophysical importance. Very careful measurement of cross sections for astrophysical calculations often leads to new nuclear structure and nuclear physics information, particularly with respect to the direct capture process which is often important at low energy in light ion reactions.

The rate at which 12C is converted to 16O in the core of red giant stars is determined by the tails of two sub-threshold states in 16O, a 1- state at 7.117 MeV and a 2+ state at 6.917 MeV. In a study of the beta-delayed, alpha-particle spectrum of 16N, a Toronto-TRIUMF led collaboration was able to place much improved limits on the contribution of the 7.117 MeV state to the rate of formation of 16O. At present, the decay of 17Ne to 17F, which subsequently decays to 16O plus a proton, is being studied as a possible method for determining the contribution of the 6.917 MeV state to the 16O formation process.

Explosive processes such as supernovae, novae, X-ray bursters and gamma-ray bursters, are the subject of intense experimental and theoretical investigation at the present. The ISAC-1 project, whose objective is to produce intense accelerted beams of selected radioactive species will allow reactions of short-lived nuclei with hydrogen or heluim to be studied in the laboratory, thereby providing important information on some of the reactions which occur during these very brief astrophysical events.

Recent Publications

``Branching ratios for the decay of the 8.78 and 8.91 MeV states of 14N'', J.D. King, Can. J. Phys. 69, pp. 828-29 (1991).

``The beta-delayed alpha spectrum of 16N and the 12C(alpha gamma)16O cross section at low energies'', L. Buchmann, R.E. Azuma, C.A. Barnes, J. D'Auria, M. Dombsky, U. Giesen, K.P. Jackson, J.D. King, R. Korteling, P. McNeely, J. Powell, G. Roy, J. Vincent, T.R. Wang, S.S.M. Wong and P.R. Wrean, Phys. Rev. Lett. 70, pp. 726-29 (1993).

``Cross section and astrophysical S-factor for the 13C(p gamma)14N reaction'', J.D. King, R.E. Azuma, J.B. Vise, J. Görres, C. Rolfs, H.P. Trautvetter, and A.E. Vlieks, Nucl. Phys. A567, pp. 354-76 (1994).

``The beta-delayed alpha-decay of 17N'', M. Dombsky, L. Buchmann, J. D'Auria, U. Giesen, K.P. Jackson, J.D. King, E. Korkmaz, R. Korteling, P. McNeely, J. Powell, G. Roy, M. Trinczek and J. Vincent, Phys. Rev. C49, pp. 1867-71 (1994).

``Constraints on the 12C(alpha, gamma)16O cross section at low energies from the beta-delayed alpha-spectrum of 16N'', R.E. Azuma, L. Buchmann, F. Barker, C.A. Barnes, J. D'Auria, M. Dombsky, U. Giesen, K.P. Jackson, J.D. King, R. Korteling, P. McNeely, J. Powell, G. Roy, J. Vincent, T.R. Wang, S.S.M. Wong and P.R. Wrean, Phys. Rev. C50, pp. 1194-1215 (1994).