B.A. Robson

Study of 16O(d, d)16O and 16O(d, p)17O using polarized deuterons

Abstract Cross sections and vector and tensor analysing powers have been measured for 16 O(d, d) 16 O, 16 O(d, p 0 ) 17 O and 16 O(d, p 1 ) 17 O ∗ at bombarding energies of 9.3 and 13.3 MeV. For the elastic scattering, cross-section and vector-analysing-power data are reasonably well reproduced by optical-model calculations, but only rough qualitative agreement with the tensor analysing power is obtained. Some improvement in the agreement with the tensor-analysing-power data results if a tensor term T R is included in the optical potential. A degree of correspondence with the (d, p 0 ) data at 9.3 MeV is achieved using DWBA calculations which take into account the D-state of the deuteron and the tensor potential T R . For E d = 13.3 MeV, the general features of all the (d, p 1 ) data except T 21 (θ) can be realized using only an 1 · s spin dependence in the optical potentials. Non-stripping mechanisms appear to be operative in the (d, p) reactions, particularly at the lower energy.

Deuteron-induced reactions in 6Li, 9Be and 10B at bombarding energies of 4.5 TO 6.0 MeV

Abstract Angular distributions for the reactions 6 Li(d, p) 7 Li (ground state and 0.48 MeV level), 9 Be(d, p) 10 Be (ground state and 3.37 MeV level), 10 B(d, p) 11 B (ground state, 2.12, 4.44 and 5.02 MeV levels) and the elastic scattering of deuterons on 6 Li and 9 Be have been measured for bombarding energies between 4.5 and 6.0 MeV. Absolute cross sections have been obtained for the 9 Be+d data. An analysis of the data has been made using the optical-model and the distorted-wave and Hauser-Feshbach theories.

j-dependence in l = 1 transitions in Cr(d, p) reactions

Abstract The j-dependence of several ; l = 1 transitions in the 50Cr(d, p)51Cr and 52Cr(d, p)53Cr reactions at 7.5 and 8.0 MeV deuteron bombarding energy, respectively, has been qualitatively described using the distorted-wave theory. This description required a rather different deuteron potential from that obtained by fitting elastic-scattering data which implies that the distorted-wave theory is not strictly valid. If the deuteron parameters are essentially the same for each transition, the angular distributions for J = 1 2 and J = 3 2 levels are systematically different at backward angles, and the difference is a consequence of the deuteron and proton spin-orbit interactions. The Lee-Schiffer rule may be interpreted in this manner. The transition to the 1.895 MeV level in 51Cr is found to violate the j-dependence rule probably because of unusually large corrections occurring in this case.

A deep potential description of the 16O+16O system

Abstract Resonant phenomena in the 16 O+ 16 O system are described successfully in terms of an ion-ion potential which is sufficiently deep to support wavefunctions with the proper number of radial nodes, consistent with the Pauli principle. Possible candidates for quasimolecular states in 32 S are indicated.

Deuteron induced reactions on 14N

Abstract The absolute differential cross sections for the reactions 14 N(d,p) 15 N( E x = 5.28, 5.31, 6.33, 7.16, 7.31, 7.57 and 8.32 MeV), 14 N(d, α) 12 C ( E x = 0, 4.433, 7.656 and 9.64 MeV) and for the elastic scattering of douterons on 14 N were measured in the energy range 1.0 ≦ E d ≦ 3.1 MeV. These data are analysed using the optical model and the Hauser-Feshbach and DWBA theories.

DWBA calculations for (d, p) reactions including the D-state of the deuteron

Abstract The effect of the deuteron D-state on DWBA calculations for deuteron stripping has been studied for l = 1 transitions in the 52Cr(d, p)53Cr reaction leading to the ground ( 3 2 − ) and 0.57 MeV ( 1 2 − ) states. The D-state has been included in an exact treatment using a soft-core neutron-proton potential and the corresponding deuteron wave function of Reid. The effect upon the j-dependence of the differential cross sections and the corresponding vector and tensor analysing powers has been investigated.

j-dependence of l = 1 transitions in the 54Cr(d, p) 55Cr reaction

Abstract Differential cross sections for six l = 1 transitions in the reaction 54 Cr(d, p) 55 Cr have been measured at a deuteron bombarding energy of 8 MeV. The data have been described qualitatively by DWBA calculations employing spin-orbit terms in the deuteron and proton optical model potentials to reproduce the observed dependence on j . Spin assignments of 3 2 , 1 2 , 3 2 , 1 2 and 1 2 have been made for the ground, 0.245, 0.573, 1.487 and 2.905 MeV states in 55 Cr. The 2 p 1 2 and 2 p 3 2 spectroscopic factor sums were found to be 0.66 and 0.56 respectively indicating a large admixture of (2 p 1 2 ) 2 configurations in the ground state of 54 Cr.

Application of an inverse-scattering method to determine the effective interaction between composite particles

Abstract An inverse-scattering method developed recently by Munchow and Scheid is used to determine the effective potential between two α-particles. The α-α scattering phase shifts from a microscopic calculation using the generator coordinate method are employed with the inversescattering technique to obtain a unique , energy-dependent optical potential. A comparison of this potential with the direct (or folded) potential clearly reveals the Pauli exchange effects arising from the inclusion of nuclear exchange between the two a-particles. It is shown that the inverse-scattering approach is accurate for the α-α system even at low energies and should be applicable to heavy-ion systems.

Deuteron-induced reactions in 12C at bombarding energies of 5 to 10 MeV

Abstract Absolute differential cross sections for the reactions 12 C(d, p) 13 C leading to the ground state and the 3.09, 3.68 and 3.85 MeV excited states, 12 C(d, α) 10 B for the ground state and 0.717 MeV residual level and the elastic scattering of deuterons on 12 C have been measured for bombarding energies of 5 to 10 MeV. An analysis of these measurements has been performed using the optical model and distorted-wave and Hauser-Feshbach theories.

The 27Al(3He, α)26Al reaction at 10 MeV bombarding energy

Abstract The reaction 27Al(3He, α)26Al has been studied at 10 MeV bombarding energy. Angular distributions were measured for the ground state and the first (0.229 MeV), second (0.418 MeV), third (1.059 MeV), “fourth” (1.760/1.852 MeV) and “sixth” (2.07/2.08) MeV excited states in 26Al. The spectra were recorded at every 5° between 15° and 165°(lab). The direct-interaction contributions to the cross sections were calculated using the distorted wave Born approximation and are compared with the observations. The effects of both a finite-range interaction and the non-locality of the optical potentials are also considered. For optical-model parameters which describe the related elastic scattering results, an l = 2 neutron transfer was found to be most consistent with the data in all cases except for the transitions to the 1.760/1.852 MeV levels, which do not seem to proceed via a direct interaction. Relative spectroscopic factors have been determined and are in good agreement with a simple model in which 27Al and 26Al consist only of ( d 5 2 ) −1 and ( d 5 2 ) −2 configurations.