R. Santo

Effects of α-particle correlations in elastic α-scattering

Abstract Elastic α-scattering angular distributions from 36, 40 Ar, 40, 42, 44, 48 Ca and 41 K have been measured at several energies between 18 and 29 MeV. The data show an anomalous backward rise in the angular distributions of the N = Z nuclei 36 Ar and 40 Ca as compared to 40 Ar and 44 Ca. This backward angle enhancement and its irregular energy dependence are interpreted as due to the interaction of the incident α-particles with α-particle clusters within the N = Z nuclei. Excess neutrons destroy the correlation effects. Consequences for other reactions involving α-particles are discussed.

The reactions 64Zn(3He, d)65Ga and 64Zn(3He, α)63Zn

Abstract The reactions 64 Zn( 3 He, d) 65 Ga and 64 Zn( 3 He, α) 63 Zn have been studied at incident 3 He energy of 18 MeV using a broad range magnetic spectrograph and an E -d E telescope. Angular distributions have been obtained and are analysed by the DWBA theory. The results give information about the 64 Zn ground state configuration as well as the neutron hole states in 63 Zn and the single proton states in 65 Ga, respectively.

Investigation of the (3He, p) reaction on the Ca isotopes A = 42, 43, 44 and 48

Abstract The ( 3 He, p) reaction on the Ca isotopes A = 42, 43, 44 and 48 has been investigated at 15 and 18 MeV incident energy using a magnetic spectrograph. Angular distributions have been measured and analysed by means of the DWBA. Spins and L -values for the final levels in the Sc nuclei have been deduced. The spectra are compared with the results of shell-model calculations. For the reaction 48 Ca( 3 He, p) 50 Sc a quantitative analysis of the cross sections has been performed using the wave functions of Hughes and Soga. The systematics of the ( 3 He, p) cross sections for transitions to analogue states has been studied by measurements on a target consisting of a mixture of several Ca isotopes. A consistent DWBA analysis for these as well as for the corresponding (t, p) transitions has been performed.

Comparison of elastic deuteron scattering from neighbouring nuclei

Abstract The elastic scattering of 11.8 MeV deuterons on isotopes of various nuclei between Al and Ni has been measured and analysed in terms of the optical model. The data show significant differences between neighbouring isotopes of the same element, particularly for lighter target nuclei. In the optical-model analysis this behaviour is reflected in variations of the imaginary potential parameters. The difference in the angular distributions of neighbouring isotones are found to be much smaller. Obviously, this behaviour cannot be explained by an isospin dependent potential as in the case of proton scattering, where similar effects have been observed. Some correlations between the imaginary potential and β 2 values extracted by DWBA analysis of inelastic scattering from the first excited 2 + states are indicated.

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.

Level structure of 49V deduced from 50Cr(t, α) and 48Ti(3He, d) reactions

Abstract The level scheme of 49V has been investigated using the 50 Cr ( t , α) and 48 Ti ( 3 He , d ) reactions. Angular distributions have been measured and spectroscopic factors have been extracted by DWBA analysis. The data indicate particle-hole and configuration mixing in the proton states involved. The excitation of states of the ( f 7 2 ) 3 configuration is discussed in connection with possible target excitation processes.

LEVEL STRUCTURE OF

Abstract The level scheme of 49V has been investigated using the 50 Cr ( t , α) and 48 Ti ( 3 He , d ) reactions. Angular distributions have been measured and spectroscopic factors have been extracted by DWBA analysis. The data indicate particle-hole and configuration mixing in the proton states involved. The excitation of states of the ( f 7 2 ) 3 configuration is discussed in connection with possible target excitation processes.

sup 49

Abstract Using the counter telescope technique, angular distributions of tritons from (d, t) reactions on Be 9 , A 40 , Y 89 , Zr 91, 92, 94, 96 and Pb 208 have been measured between 20° and 90° in steps of 5°. Besides the excitation of the ground state, transitions to the lowest excited states have been observed in several cases. The data have been analysed in terms of the DWBA and PWBA theory. In several cases l values, spectroscopic factors and values of the parameter Λ have been determined.

V DEDUCED FROM

Abstract The elastic 3 He scattering on 40 Ca, 44 Ca, 48 Ca, 46 Ti, 48 Ti, 50 Ti, 50 Cr, 52 Cr and 53 Cr has been investigated at E 3He = 29 MeV from θ = 14° up to θ = 160°. Average sets of parameters have been obtained from optical-model analyses describing the data on the different nuclei equally well, except 40 Ca. The back-angle data were found to be most sensitive to the spin-orbit potential used. The anomalous back-angle enhancement of the 40 Ca( 3 He, 3 He) cross section is discussed in connection with similar anomalies in elastic α-scattering.

sup 50

Abstract Inelastic 3 He scattering to positive parity states in 44 Ca, 46 Ti, 48 Ti, 50 Ti and 50 Cr and has been measured at 29 MeV and analysed within the microscopic model. With theoretical f 7 2 wave functions and a Gaussian of 1.85 fm width for the effective interaction a constant value of about 50 MeV has been obtained.