M. Hyakutake

One- and two-step processes in (p, t) transitions to the quadrupole- and octupole-vibrational states in 122,128Te

Abstract A second-order DWBA analysis is performed for the 124,130 Te(p, t) 122,128 Te reactions at E p = 51.9 MeV. It is found that the (p, t) excitations of one-phonon 2 1 + and 3 1 − states in 122 Te receive large contributions from inelastic two-step processes, while those of 128 Te receive dominant contributions from one-step processes.

Elastic scattering of 119 MeV 3He particles and energy and mass-number dependence of optical potential parameters

Abstract The elastic scattering of 119 MeV 3 He particles by 12 C, 27 Al, 58,60,62,64 Ni, 59 Co, 90,92 Zr and 89 Y has been investigated over a wide angular range in order to study the mass-number dependence of the optical potential and odd-even differences in the elastic scattering. The elastic scattering cross sections have been analyzed in terms of the optimal model. The data, except for 12 C, 27 Al and 59 Co, were fitted with r R = 1.21 fm, a R = 0.76 fm and r I = 1.17 fm, fixed at the average values. The following formulae were obtained for the three remaining parameters by combining with the energy dependence of the parameters (90–120 MeV) obtained previously: V=111.4−0.173E+ Z A 1 3 +14.9 N−Z A ( MeV ) W D =24.8−0.028E ( MeV ) , a I =0.754+0.78 N−Z A ( fm ) The depths of the valleys of the angular distribution in the case of 59 Co (I = 7 2 ) are considerably shallower than those for Ni isotopes, while the depths in the case of 89 Y (I = 1 2 ) are nearly the same as those for Zr isotopes. Thus it may be concluded that the odd-even differences are attributed to the scattering from the quadrupole moment of the odd- A nucleus (if I > 1 2 ).

Elastic scattering of 90–120 MeV 3He particles and an unambiguous optical potential

Abstract The elastic scattering of 109.2 MeV 3 He particles by 40 Ca, 58 Ni, 90 Zr and 116 Sn has been investigated over a wide angular range. The elastic scattering cross sections have been analyzed in terms of the optical model. The data for each nucleus studied were sufficient to eliminate the discrete ambiguity in the strength of the optical potential; the unique potential which fits the data has a real well depth of about 100 MeV and a corresponding volume integral per nucleon pair of about 310 MeV · fm 3 . The elastic scattering of 3 He particles by 58 Ni has been further measured at bombarding energies of 89.3 and 118.5 MeV, and the incident-energy dependence of the optical potential of 3 He particles for 58 Ni was obtained.

Elastic and inelastic scattering of 51.9 MeV protons by doubly even tellurium nuclei

Abstract Measurements of elastic and inelastic proton scattering by isotopically enriched targets of 122 Te, 124 Te, 126 Te, 128 Te and 130 Te have been carried out with a 51.9 MeV proton beam. In all isotopes, differential cross sections were measured for five to nine excited states up to 3–4 MeV excitation energy. Optical-model analyses are made of the elastic scattering and best-fit optical-model parameters are obtained. Inelastic scattering data are analyzed by distorted-wave Born-approximation (DWBA) calculations using a complex form factor. Deformation parameters are obtained and compared with previously measured values. For the elastic scattering and one-phonon 2 + and 3 − states, coupled channel calculations (0 + − 2 + − 3 − ) are made. Finally, the splitting of the octupole strength, the hexadecapole vibration and the possible 2 5 pole vibration in even tellurium nuclei, are discussed.

Effect of inelastic scattering processes on (p, t) reactions exciting the first 2+ states in Te, Sn and Cd isotopes

Abstract Differential cross sections of (p, t) reactions exciting the 2+1 states in Te (A = 128 − 120), Sn (116 and 114) and Cd (114 and 112) have been measured at Ep = 52 MeV. The observed differences of the angular distributions are interpreted by taking into account the two-step processes through inelastic scattering channels.

Excitation of 3−1, 5−1 and 7−1 states in Te isotopes A = 120, 122; 124, 126, 128 WITH (p, t) reactions

Abstract The reactions A Te(p, t) A −2 Te have been studied with even- A targets using 51.9 MeV protons. Three or more strongly excited triton peaks were observed in the spectra of the A -2 Te nuclei at energies of ≈ 2–3 MeV excitation. Angular distributions are analyzed using DWBA theory. The lowest octupole (3 − 1 ) states of five Te isotopes are strongly excited. The lowest 3 − state in 120 Te is established at 2.09 ±0.02 MeV. The systematics of excitation energies and cross sections for the lowest 5 − and 7 − states are interpreted by a quasiparticle model.

Inelastic proton scattering on doubly even selenium isotopes

Abstract Measurements of elastic and inelastic proton scattering by isotopically enriched targets of 76 Se, 78 Se, 80 Se and 82 Se have been carried out using a 51.9 MeV proton beam. Inelastic proton scattering to one-phonon 2 + and 3 − states is analyzed by DWBA and coupled channel theories. The deformation parameters obtained are compared with those extracted from electromagnetic excitation, and the prescription of Madsen, Brown and Anderson for the difference of deformation parameters for different transitions has been tested. Additional information on one-phonon cotupole (3 − ) states in 76 Se, 78 Se, 80 Se and 82 Se is presented.

Strength functions of deeply bound hole states in 111, 115, 119, 123Sn

Abstract Deeply bound hole states in 111,115,119,123Sn have been investigated with high resolution (p, d) experiments at the bombarding energy of 50 MeV. The fine structure and neutron number dependence of the strength functions of the 1 g 9 2 and 2 p (2 p 1 2 + 2 p 3 2 ) hole states have been determi The resulting strength functions and the spreading widths were compared with predictions of the nuclear damping calculations by Soloviev, Stoyanov and Vdovin and by Bortignon and Broglia.

Spin-parity assignments for the excited states of 91Nb from the 91Zr(p, nγ)91Nb reaction

Abstract The energy levels of 91Nb were studied by means of the (p, nγ) reaction. The de-excitation γ-rays were observed with a Ge(Li) detector in the proton energy range from 3.25 to 5.51 MeV in steps of about 30 keV. Resonances attributed to isobaric analog states in the compound system 91Nb were observed in the excitation functions of the de-excitation γ-rays. From an analysis of these analog resonances, a Hauser-Feshbach analysis and the γ-decay scheme, the spin-parities of the levels up to 2792.6 keV (22 levels) were assigned.

Scattering of 14.1 MeV Neutrons from Fe

Differential cross sections for the elastic scattering of 14.1 MeV neutrons from Fe and for the inelastic scattering to the first excited state at 0.85 MeV have been measured. The inelastically scattered neutrons were completely separated from elastically scattered ones by a time-of-flight spectrometer which had an energy resolution of 260 KeV for 14.1 MeV neutrons. The angular distributions for elastic and inelastic scattering have been analyzed by the optical model and the distorted wave Born approximation (DWBA), respectively. Both elastic and inelastic scattering have also been analyzed using the coupled channel calculations. Reasonable fits to the data were obtained. The deformation parameters extracted are compared with those found from other experiments.