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81.
D. Evers C. Ley E. Spindler W. Assmann K. Rudolph P. Konrad P. Sperr 《Nuclear Physics A》1977,275(2):363-380
The (3He, n) reaction on 16O and 18O has been used to study low-spin states in 18Ne and 20Ne up to Ex ≈ 8 and 20 MeV, respectively. The measured neutron angular distributions have been analysed using DWBA. By a comparison with shell-model calculations in the (s, d) shell it is found that most of the two-proton transfer strength can be explained within that shell. Important contributions, however, from the (f, p) shell in low-lying negative parity states are also present. 相似文献
82.
K. Umeda T. Yamaya T. Suehiro K. Takimoto R. Wada E. Takada S. Shimoura A. Sakaguchi S. Murakami M. Fukada Y. Okuma 《Nuclear Physics A》1984,429(1):88-104
The differential cross sections for the (d, 6Li) reaction on targets of 12C, 16O, 24Mg, 40Ca, 58Ni and 94Mo have been measured at Ed = 54.2 MeV. The measured angular distributions have been analyzed by finite-range DWBA calculations, and spectroscopic factors for an α-cluster transfer have been extracted. In the DWBA analysis using an optical model with a phenomenological Woods-Saxon potential, the spin-orbit part of the deuteron optical potential played a significant role in reproducing the measured angular distributions but the spin-orbit part of the 6Li optical potential had a minor effect. Relative spectroscopic factors extracted from the present data were compared with theoretical predictions together with the results from the (p, pα) reaction. The relative spectroscopic factors for 1p-shell nuclei were in quantitative agreement with theoretical predictions. However, there were certain discrepancies between the spectroscopic factors extracted from the (d, 6Li) reaction and those from the (p, pα) reaction, and the discrepancies increased with target mass number. 相似文献
83.
J.C. Steckmeyer F. Lefebvres C. Le Brun J.F. Lecolley M. lHaridon A. Osmont J.P. Patry 《Nuclear Physics A》1984,427(2):357-396
The angular momentum transferred to fragment spins has been studied in the damped nuclear reactions Ar+Bi at 255 MeV and 295 MeV and Ni+Pb at 435 MeV from measurement of the angular distribution of the fission fragments of the heavy-recoil nucleus in coincidence with the projectile-like fragment. The heavy-fragment spin is strongly aligned along the normal to the reaction plane and the rigid-rotation limit of the dinuclear system is attained. The dealignment mechanisms produce spin components mainly located in a plane approximately perpendicular to the heavy-recoil lab direction. They are well described by a dynamical model based on the nucleon exchange between the two ions during the collision. The spin-component fluctuations reach high values. In the heavy-recoil direction, these fluctuations are increasing with the total kinetic energy loss and the charge transfer from the projectile to the target. The spin values extracted from both the angular distributions and the fission probabilities are seen to be compatible. 相似文献
84.
W. Buck F. Hoyler A. Stäbler G. Staudt H.V. Klapdor H. Oeschler 《Nuclear Physics A》1983,398(2):189-202
The differential cross sections for the 11B(p, α)8Be and 23Na(p, α)20Ne reactions were measured at bombarding energies between 6 and 24 MeV. The observed angular distributions can be divided into two domains: at low energies the shapes vary rapidly with incident energy indicating a compound nucleus reaction ; at higher energies rather stable diffraction patterns are seen exhibiting a direct reaction mechanism and DWBA calculations are able to describe the shapes. The change from one region to the other is rather abrupt and this behaviour seems typical for reactions having an α-like compound nucleus. The energy at which this change occurs corresponds to an excitation energy in the compound nucleus of about 20 MeV above the α-threshold. 相似文献
85.
L. Głowacka M. Jaskóła J. Turkiewicz L. Zemło M. Kozłowski W. Osakiewicz 《Nuclear Physics A》1977,284(2):257-263
The energy spectra of α-particles emitted in the 161Dy(n, α)161Gd and 163Dy(n,α)160Gd reactions have been measured at neutron energies equal to 14.1 and 18.2 MeV. The results have been analysed in terms of Hauser-Feshbach, pre-equilibrium and knock-on models. The experimental data can be described assuming the existence of preformed α-clusters in target nuclei and the processes involving only few degrees of freedom. 相似文献
86.
D. Konnerth W. Trombik K.G. Bernhardt K.A. Eberhard R. Singh A. Strzalkowski W. Trautmann 《Nuclear Physics A》1985,436(3):538-560
We have studied elastic scattering, inelastic scattering and several transfer channels of the systems 14C + 14C and 14C + 12C over a wide range of energies up to Ec.m. = 35 eMeV and 32 MeV, respectively. The reaction channels were identified by means of kinematic coincidences between solid-state detectors, γγ coincidences were measured to determine cross sections for mutual inelastic scattering of 14C + 14C.Pronounced regular gross structures, similar to those found for 16O + 16O, are observed in the elastic excitation function of 14C + 14C at θc.m. = 90°, The angular distributions measured at the energies of the maxima and an optical-model analysis suggest that one or a few surface partial waves dominate the scattering behaviour. Correlated structure of narrower width is found in the inelastic channels and, to a lesser degree, in the transfer channels which appear with rather small cross sections.In 14C + 12C elastic scattering the gross structures are strongly fragmented, in contrast to 14C + 14C but similar to 12C + 12C. While the 12C(2+) excitation is very weak, the observed strengths of the 14C(3?) excitation and of neutron transfer point to a substantial role of these channels as coupling partners to the elastic configuration and to their influence on the elastic scattering behaviour. A correlated intermediate structure is observed near 23.5 MeV, where a dominance of l = 18 is suggested by the elastic scattering angular distribution. This unexpectedly high l-value exceeds lgraz at this energy by at least two units of ?. 相似文献
87.
J. Carter R.G. Clarkson V. Hnizdo R.J. Keddy D.W. Mingay F. Osterfeld J.P.F. Sellschop 《Nuclear Physics A》1976,273(2):523-532
Angular distributions for 16O + 24Mg and 12C + 24Mg elastic and inelastic (2+, 1.37 MeV state in 24Mg) scattering have been measured at energies spanning the Coulomb barrier. Apart from the structure typical of strong destructive Coulomb-nuclear interference, the data exhibit some additional specific features. Coupled channel calculations were performed, along with DWBA calculations to analyse the data using fixed coupling strengths deduced from the results of Coulomb excitation work. The importance of higher-order effects such as reorientation, is demonstrated. 相似文献
88.
89.
J.F. Petersen 《Nuclear Physics A》1975,255(2):307-314
The two-proton transfer reaction (3He, n) has been measured on four gas targets, 16O, 18O, 20Ne, and 22Ne, with an incident 3He energy of 18.3 MeV. The data were taken with a neutron time-of-flight spectrometer in the angular range 0° to 40° c.m. The results for selected transitions are compared to DWBA predictions using shell-model spectroscopic amplitudes. In addition, the data for the 18O(3He, n)20Ne reaction are compared to predictions of the SU(3) strong coupling model. 相似文献
90.
The elastic scattering, inelastic scattering, single-neutron transfer reactions 13C(17O, 16O) 14C, 13C(17O, 18O)12C and 13C(17O, 18O2+, 1.98)12C, and seven other exit channels which involve 7Li, 9Be, 11B and 15N have been measured for the system 17O+13C at 12.9 and 14 MeV c.m. It is shown that all reactions mentioned above have significant contributions from compound nuclear decay, following fusion of projectile and target. 相似文献