J. W. Koen
Stellenbosch University
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Featured researches published by J. W. Koen.
Nuclear Physics | 1974
N. J. A. Rust; W. J. Naude; J. W. Koen; W.L. Mouton
Abstract The spins and electromagnetic properties of levels up to 1800 keV in 45Sc were studied by means of inelastic proton scattering. Results are discussed with reference to the excited-core model.
Nuclear Physics | 1999
M.B. Chadwick; D.T.L. Jones; G.J. Arendse; A. A. Cowley; W.A. Richter; J.J. Lawrie; R.T. Newman; J.V. Pilcher; F. D. Smit; G. Steyn; J. W. Koen; J. A. Stander
Model calculations of proton-induced nuclear reaction cross sections are described for biologically-important targets. Measurements made at the National Accelerator Centre are presented for double-differential proton, deuteron, triton, helium-3 and alpha particle spectra, for 150 and 200 MeV protons incident on C, N, and O. These data are needed for Monte Carlo simulations of radiation transport and absorbed dose in proton therapy. Data relevant to the use of positron emission tomography to locate the Bragg peak are also described.
European Physical Journal A | 1993
L. D. Olivier; W. A. Richter; J. A. Stander; J. W. Koen
Levels up to 9.3 MeV excitation in22Ne were studied with the19F(α, pγ)22Ne reaction atEα = 12 MeV. Level energies, branching ratios, mean lifetimes, spins and mixing ratios were obtained for a number of levels. Relevant results are compared with many-particle shell-model calculations.
European Physical Journal A | 1980
J. J. Buitendag; W. J. Naude; R. Saayman; N. J. A. Rust; J. W. Koen
The spins and electromagnetic properties of levels in45Sc up to 2,352 keV were studied by means of inelastic proton scattering using a 3-parameter coincidence arrangement and Coulomb excitation with3He and4He beams. Relevant experimental results are discussed in terms of the Thankappen-True core-plus-particle model.
Nuclear Physics | 1970
P. R. de Kock; J. W. Koen; W.L. Mouton
Abstract The lifetimes of the lowest bound states of 26 Mg and 29 Si were determined by means of Doppler shift attenuation measurements. The results are τ m = 300 +100 −60 95±25, > 5000and 2100 +4000 −1000 fs for 26 Mg (1) through (4) and τ m = 560±130, 830±260 and 24±14 fs for 29 Si (1) through (3), respectively.
European Physical Journal A | 1980
P. Haupt; J. W. Koen; W. J. Naude; N. J. A. Rust
Levels up to 3,016 keV in59Co were studied using the59Co (p, p′y) and56Fe (α, py) reactions. Level energies, branching ratios, mean lifetimes and spins were obtained for a number of levels.
European Physical Journal A | 1980
J.C. Van der Merwe; W. J. Naude; R. Saayman; J. W. Koen; N. J. A. Rust
The spins and electromagnetic properties of levels up to 3,700 keV in51V were studied by means of inelastic proton scattering. Results are discussed with reference to the many-particle shell model using effective surface delta and realistic Kuo-Brown interactions.
Annals of Physics | 1968
P. R. de Kock; J. W. Koen; W.L. Mouton
Abstract Gamma radiation from the decay of two resonances in the reaction 26Mg(p, γ)27Al at Ep = 1.785 MeV and 1.965-MeV, have been resonantly absorbed in aluminium to excite the states at 9.991 MeV and 10.165 MeV, respectively. In addition the γ-decay of the resonances have been studied in detail and angular distribution and yield measurements of the ground-state radiation performed. The following results were obtained: 9.991-MeV Level 10.165-Mev Level J π 7 2 (−) 5 2 + Γ t 1.2 ± 0.3 eV 23 ± 3 eV Γ p 0.5 ± 0.2 eV 22 ± 3 eV Γ γ 0.7 ± 0.2 eV 1 ± 5 eV The spin of the 9.629-MeV state in 27Al, excited at Ep = 1.409 MeV, was also determined and found to be 1 2 .
European Physical Journal A | 1987
S. Froneman; W. J. Naude; W. A. Richter; J. A. Stander; J. W. Koen
Properties of levels up to 3.5 MeV in43Sc were studied using40Ca (α, p)43Sc and40Ca(α, pγ)43Sc reactions atEα=12 MeV. Level energies, branching ratios, mean lifetimes, spins and mixing ratios were obtained for a number of levels. Relevant results are compared with many-particle shell-model predictions.
European Physical Journal A | 1986
J. A. Stander; W. J. Naude; R. Saayman; J. W. Koen
The atomic nucleus41K was studied with emphysis on the experimental derivation of electromagnetic properties and spin values of low-lying levels with energies ≦3,282 keV. Energy levels, decay properties and mean lifetimes were measured with (p, p′ γ) and (p, p′) reactions at incident proton energies of about 6 MeV. Spin values were deduced from a comparison of results obtained from a Hauser-Feshbach analysis of (p, p′) and (p, p′ γ) reactions and measured transition strengths derived from mixing ratios, lifetimes and decay properties. Experimental results are discussed in terms of shell model calculations with a modified effective surface delta interaction.
