R. Stock

(3He, α) reactions on the chromium isotopes

Abstract The reactions 50,52,53,54Cr(3He, α)49,51,52,53Cr have been studied at an incident energy of 18 MeV using a broad-range magnetic spectrograph as well as solid state detectors. Angular distributions were obtained for all isotopes. The relative isotopic cross sections were accurately determined by measurements with a target of mixed Cr isotopes. Coulomb energy displacements are obtained from the observation of f 7 2 , d 3 2 and s 1 2 analogue states at excitation energies between 5 and 13 MeV. The spectroscopic factors from a DWBA analysis give information about the neutron configurations in the Cr isotopes which are discussed in the particle-hole excitation picture and in terms of the unified model. Centres of gravity for the f 7 2 , d 3 2 , and s 1 2 orbits are determined. The spectroscopic factors of the analogue states are obtained from solutions of the Lane equations for the bound states using a surface-type isospin potential. In a simplified analysis, the effects of the surface potential are simulated by varying the bound-state radii, keeping the depth of the potential constant for the ifT states. These procedures yield similar results, which are in agreement with the sum-rule predictions. The resulting radii suggest that the inner nucleons occupy a volume smaller than that corresponding to a potential radius R = 1.25 A 1 3 .

Anomalous spectroscopic factors for 40Ca(3He, α) 39Ca as compared to other pickup reactions on Ca isotopes

The (p, d), (d, t) and (3He, α) reactions on mixed 40, 42, 44, 48Ca target were measured at Ep=19.5 and 20 MeV, Ed=17 MeV and at 3He energies between 14 and 28 MeV. All the strengths deduced from (p, d) and (d, t) agree with expectations, whereas the d32 strength of 40Ca obtained from (3He, α) largely exceeds the sum rule limit and shows a strong energy dependence. A possible connection with the anomaly of elastic α scattering from 40Ca is discussed.

Investigation of the 43Ca(3He, α)42Ca and 41K(d, p)42K reactions

The 43Ca(3He, α) reaction has been measured at 18 MeV. A large number of configuration states as well as eight analogue states have been identified in 42Ca. Their parent states have been investigated in a 41K(d, p)42K experiment at 12 MeV. Spin assignments for some level in 42K are discussed. The spectroscopic factors are compared with shell-model calculations of Dieperink and Brussaard.

Interference between inelastic scattering and transfer in the scattering of 16O ON 17O

Abstract Angular distributions and an excitation function of the reaction 17O(16O, 16O)17O∗ ( 0.871, 1 2 + ) have been measured. The observed fine structure of the angular distributions cannot be explained by the dominating transfer process alone. An explanation is given in terms of interference between one-neutron transfer and inelastic scattering.

The (1f72)2 multiplet in 42Ca

Abstract The states of 42Ca below 3.2 MeV excitation are studied by the 41Ca(d,p)42Ca reaction at 12 MeV bombarding energy. The experimental spectroscopic factors are compared to predictions based on Gerace and Greens coexistence model.

Angular distributions of the 90Zr(d, p) reaction and the coupling of analogous (d, p) and (d, n) channels

Abstract The excitation functions and spectroscopic factors of several final levels in the reaction 90 Zr(d, p) show an anomaly at the threshold energy for the (d, n) reaction to the 91 Zr ground state analog 91 Nb. This indicates a more complicated coupling of the (d, n) and (d, p) analog channels than described by the two channel approach.

Particle-hole states in 41Ca and analog states of 41K, observed in the 42Ca(3He, ) reaction

Abstract The level structure of 41 Ca has been investigated using the 42 >Ca ( 3 He ,α) 41 Ca reaction at E( 3 He ) = 18 MeV . Evidence for particle-hole components in 41 Ca and 42 Ca is found, in particular by the detection of 7 2 − excited states in 41 Ca. Several analogue states of levels in 41K are identified.

STUDY OF

Abstract The reactions 64Zn(t, α) 63Cu and 66Zn (t, α)65Cu have been studied at incident triton energy of 13 MeV using a broad-range multi-angle spectrograph. Angular distributions up to an excitation energy of about 4.5 MeV have been obtained and are analysed by the DWBA theory. The results provide information about the 64, 66Zn ground state configurations as well as the proton hole states in 63Cu and 65Cu. Some evidence is found for inelastic mechanisms affecting the magnitude of pickup cross sections for levels with large collective components.

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Abstract The reactions 64Zn(t, α) 63Cu and 66Zn (t, α)65Cu have been studied at incident triton energy of 13 MeV using a broad-range multi-angle spectrograph. Angular distributions up to an excitation energy of about 4.5 MeV have been obtained and are analysed by the DWBA theory. The results provide information about the 64, 66Zn ground state configurations as well as the proton hole states in 63Cu and 65Cu. Some evidence is found for inelastic mechanisms affecting the magnitude of pickup cross sections for levels with large collective components.