(D, ALPHA) REACTIONS ON NUCLEI IN MASS RANGE 24-41

The (d, α) reaction cross sections for 24Mg, 25Mg, 27Al, 32S, 35Cl, 39K and 41K have been measured as a function of deuteron energy and alpha angle over the range Ed = 4.0-5.5 MeV. The reaction mechanism has been examined by analysing the data in terms of Ericson fluctuation theory and Hauser-Feshbach theory. The observed cross sections show the behaviour expected from Ericson theory. The shapes of the average angular distributions and the relative magnitudes of the differential cross sections agree with those predicted by Hauser-Feshbach theory for states of known spin. Probable spins have been deduced for previously unassigned states of 23Na, 30P, 33S and 37Ar. The usefulness of the 2I + 1 rule is also examined. Average level widths Γ are derived from the fluctuation analysis and used in the normalization of Hauser-Feshbach calculations to obtain values of the average level spacing DJ in the compound nuclei excited at 15-21.5 MeV in the present work. These parameters are shown to have mass and excitation dependence consistent with Fermi-gas-model predictions in agreement with data obtained at lower nuclear excitation. An inhibition factor of 0.6 ± 0.2 was obtained for the isospin-forbidden transition to the 2+(T = 1) state at 2.94 MeV in 30P which corresponds to a value of 〈Hc〉 ≈ 24 keV at an excitation of 16.5 MeV in 34Cl. © 1969.