共查询到20条相似文献,搜索用时 15 毫秒
1.
Elastic scattering angular distributions of 3He particles from 9Be, 10B, 11B, 24Mg, 25Mg, 26Mg and 27A1 at E(3He) ≈ 13 to 27 MeV have been measured and some of the representative results are reported. In most cases the angular range of the measured cross sections was from 8° to 150° (lab). The results have been analyzed in terms of a six-parameter optical model and are compared with previous work. 相似文献
2.
P. Wastyn H. Genz M. Mutterer A. Richter G. Schrieder J.C. Van Staden J.P. Theobald 《Nuclear Physics A》1979,320(2):433-448
Cross sections for elastic scattering of 40Ar on 40Ca have been measured at energies Elab = 191, 236 and 272 MeV employing position-sensitive detectors and the method of kinematical coincidences. The experimental data are first compared with the ordinary and the generalized Fresnel models. Only the generalized Fresnel model describes the experimental data well. An optical model analysis with a Woods-Saxon potential yields an energy independent set of parameters (VR = ?21.76 MeV, rOR = 1.37 fm, aR = 0.45 fm; W1 = ?13.69 MeV, r01 = 1.40 fm, a1 = 0.36 fm) very similar to the one found in 40Ca-40Ca scattering at corresponding energies. Values deduced for the total reaction cross sections for the three energies are in good agreement with those predicted by the generalized Fresnel model. The data are also compared with optical model calculations with the real part of the potential replaced by various microscopically determined potentials. The proximity, Fleckner-Mosel and the Krappe-Nix-Sierk potentials like the phenomenological optical model potential reproduce the measured data fairly well over several orders of magnitude. 相似文献
3.
4.
Elastic scattering angular distributions for 10, 11B + 40Ca at Elab = 46.6 and 51.5 MeV and12C+39K at Elab = 54 and 63 MeV have been measured and compared with Woods-Saxon and double-folding optical models. The oscillatory structure observed previously for 12C + 40Ca disappears when the projectile is changed to 10,11B or the target is changed to 39K. The angular distributions are adequately reproduced by a double-folding analysis, which employs the nucleon-nucleon potential of Bertsch et al., with a range of real normalizations NR = 1.0–1.38. This same range of real normalizations was also able to describe previously measured 10,11B, 12C + 27A1 data. The double-folding analysis of 12C + 40Ca scattering indicates that this system behaves differently from neighboring systems. 相似文献
5.
S. Dahlgren D. Hasselgren B. H istad A. Ingemarsson A. Johansson P. -U. Renberg O. Sundberg G. Tibell 《Nuclear Physics A》1967,90(3):673-695
A magnetic spectrometer was used for the energy analysis of protons scattered from targets of magnesium (natural isotopic composition) and aluminium. The mean energy of the incident protons in the targets was 185 MeV. A total energy resolution of 350 keV (FWHM) was achieved, which made possible the observation of the excitation of a large number of discrete levels. Energy spectra were measured in the angular region of 4° to 40° (lab system).
The results are presented partly in the form of tables giving measured excitation energies and maximum cross sections for resolved levels and partly in the form of graphs of angular distributions of the differential cross sections.
A qualitative discussion of the results is given in terms of the multipolarities of the transitions involved and comparisons are made with similar results from other experiments in inelastic scattering and in a few cases with theoretical predictions. 相似文献
6.
M.C. Mermaz M. Ruscev M. Gai J.F. Ennis K.N. Gamadia J.F. Shriner N. Tsoupas S.M. Sterbenz D.A. Bromley 《Nuclear Physics A》1984,429(2):351-364
The 24Mg(12C, α)32S reaction has been studied in the region of the Coulomb barrier. Three angular distributions for the α-particle groups populating the ground and first-excited 2+ state of 32S have been measured spanning the apparent resonant structure observed at Ec.m = 14.20 MeV. Regge-pole and phase-shift analyses suggest a spin assignment of 8 for the corresponding resonance at Ex = 30.51 MeV in 36Ar. 相似文献
7.
Excitation functions for the 24Mg(p, γ)25Al capture reaction have been obtained for the beam energy range Ep = 0.2–2.3 MeV. The analysis of these data revealed the presence of the direct capture process to the low-lying states in 25Al at , . The presence of the weaker direct capture transitions is manifested through interference effects on the tails of the two broad resonances at Ep = 823 and 1623 keV. The deduced spectroscopic factors for these final states in 25Al are compared with the corresponding values from stripping data as well as model calculations. An astrophysical S-factor of S(0) ≈ 30 keV· b for this reaction has been obtained. 相似文献
8.
The protons and α-particles from the reactions 27Al(d, p)28Al(d, α)25Mg, 31P(d, p)32P and 31P(d, α)29Si were measured and analyzed with the channel cross correlation function and auto-correlation function to determine the correlating numbers Nd and average width 〈Γμ〉. With these values, the theoretical intermediate widths were calculated to be 119 ± 30 keV in the 29Si nucleus and 249 ± 46 keV in the 33S nucleus, which were in good agreement, within the errors, with the present experimental results of 185 ± 37 keV in 29Si and 204 ± 24 keV in 33S. 相似文献
9.
Polarization parameters have been determined for deuteron elastic scattering from 27Al, Si and 60Ni at energies between 7 and 11 MeV and laboratory scattering angles from 30° to 135°. The vector polarization, iT11, and two tensor parameters T20 and T22, were measured by scattering polarized and unpolarized deuterons which were obtained from a tandem accelerator. The largest polarization was |iT11| ≈ 0.3 and |T20| ≈ 0.2 for 27Al at 11 MeV. For 60Ni, the observed polarizations were substantially smaller. Angular distributions of the unpolarized cross section were also measured for 27Al and Si. An optical-model analysis of the polarization and cross-section data was performed. The vector polarization was reproduced reasonably well by a vector spin-orbit coupling of similar strength as found for nucleon scattering. A tensor interaction appears to be needed to account for the observed tensor polarizations. 相似文献
10.
Cross sections have been measured for the scattering of electrons through 180° from Mg, Al and Si targets in the energy range 35 to 95 MeV. Scattering from the magnetization distribution of 27Al is observed as the difference of the scattering from 27Al and from the neighbouring doubly even nuclei Mg and Si. Corrections have been applied for differences in instrumental effects and in rms charge radii. Theoretical magnetic cross sections have been computed with a single-particle wave function and with a shell-model wave function involving configuration mixing. If the distorted-wave Born approximation is used, good agreement with experiment is obtained. In both cases the best fit to the data yields a value of the oscillator range parameter b = 1.71 ± 0.06 fm. Using the q-dependence of the single-particle model a value for the magnetic octupole moment of 27Al is found. The present low-energy (E < 100 MeV) data are in good agreement with the results obtained from the scattering of high-energy (E = 500 MeV) electrons from 27Al through “normal” angles. 相似文献
11.
We use the self-consistent density-dependent Hartree-Fock field as the real part of the optical model potential. Introducing a phenomenological imaginary potential, we describe elastic scattering of protons and neutrons on 40Ca at several incident energies. Results show that the density-dependent Hartree-Fock field, including the rearrangement potential, well reproduces differential cross sections and polarizations simultaneously. This calculation explicitly shows a unified way to understand the ground-state properties and the scattering problem. Detailed study is given the properties of the non-local Hartree-Fock field, via the WKB equivalent local potential. 相似文献
12.
The elastic and inelastic scattering of 11.8 MeV vector polarized deuterons from 34S has been studied. Angular distributions of the cross section σ(θ) and vector analyzing power iT11(θ) have been measured for the ground state and the first three excited states in 34S. Optical model parameters were first obtained by fitting the elastic deuteron scattering data alone. DWBA calculations with a collective model form factor were performed for the inelastic scattering to the excited states. Coupled-channels calculations were also done both for the one-phonon and the two-phonon excited states. The optical model parameters were suitably modified to obtain simultaneous fit to elastic and inelastic data when channel coupling was introduced. The values of the vibrational parameter β2 for one- and two-phonon states are discussed and compared with those obtained from γ-decay width studies. 相似文献
13.
Elastic and inelastic scattering of 15 MeV polarized deuterons from isotopes of Ca,Cu, Sr,Zr, and Mo
The elastic and inelastic scattering of 15 MeV polarized deuterons from 48Ca, 63Cu, 88Sr, 90Zr, 92Zr, and 92Mo has been investigated. Angular distributions of the cross section and vector analyzing power iT11 have been measured for all these nuclei; the tensor analyzing powers T20 and T22 have been studied for 92Zr. Cross sections and vector analyzing powers are generally well explained by the optical model for elastic scattering and by the DWBA with a macroscopic form factor for the inelastic scattering; this is consistent with previous work. Distributions for 48Ca, however, are poorly fitted. Anomalous behavior of the N = 50 nuclei found in the inelastic scattering of polarized protons is not present for deuterons. Tensor analyzing powers are not well explained by standard procedures: use of approximate folding model optical parameters did not improve the fits. The distribution of iT11 for the ? state in 63Cu is significantly different from the distributions for the ? and ? states. 相似文献
14.
R.R. Johnson T.G. Masterson K.L. Erdman A.W. Thomas R.H. Landau 《Nuclear Physics A》1978,296(3):444-460
We have measured the angular distribution of π+ elastically scattered from . The angular range was between 13° and 165° lab. Scattered pions were detected with two counter telescopes which required pion identification through the observation of the decay muon. Data agree well with calculations derived from the free πn scattering amplitudes when absorption effects have been included. 相似文献
15.
Elastic electron scattering on 90Zr and 92Mo has been measured at 200 and 300 MeV up to 2 fm−1 momentum transfer. Data analysis led us to adopt the parabolic Gaussian shape as a valuable charge distribution for these nuclei. For 90Zr, we have compared this model with charge distributions given by recent Hartree-Fock calculations. 相似文献
16.
Analyzing powers and cross sections have been measured for elastic and inelastic scattering of 24.5 MeV protons from 20Ne and 22Ne, and for 16O, 28Si and 32S at 30.3 MeV. The experimental results were analyzed in terms of the coupled-channels formalism using the rotational model and (for 32S and 16O) the vibrational model. The results for 20Ne, 22Ne and 28Si show a systematic trend of the hexadecapole deformation. Prolate shapes for 20Ne and 22Ne and an oblate shape for 28Si are confirmed. The results for 32S are almost equally well-reproduced by the vibrational or rotational model, and there is a slight preference for the prolate shape for this nucleus. The best fits for the analyzing power for all the nuclei were obtained by using the full Thomas form for the spin-orbit potential 相似文献
17.
The (3He, t) charge exchange reaction on 24Mg and 28Si has been studied at 38.5 MeV. The angular distributions provide a number of new spin assignments in 24Al and 28P. A two-step excitation through intermediate α-particle channels was used to predict the 24Al cross sections. The fits are fair in shape, but about a factor of three too large when a perfect overlap of initial and final shapes is assumed. The data to three 1+ states of 28P are compared to the known electromagnetic reduced transition rate B(M1) to the analog states in 28Si. 相似文献
18.
19.
L. E. Antonuk D. Bovet E. Bovet J. -P. Egger J. -F. Germond F. Goetz P. Gretillat C. Lunke E. Schwarz 《Nuclear Physics A》1984,420(3):435-460
Angular distributions of π+ and π? at 100 MeV incident energy were measured for elastic and inelastic scattering from 12C and 13C. Elastic data were obtained between 6° and 180°. Inelastic scattering on the 2+ (4.4 MeV), 0+ (7.6 MeV), 3? (9.6 MeV) and 1+ (12.7 MeV) states of 12C and on the and 11.7 MeV states of 13C was mea 12C results are compared to a Δ-hole model. 相似文献
20.
H.D. Gräf H. Feldmeier P. Manakos A. Richter E. Spamer D. Strottman 《Nuclear Physics A》1978,295(2):319-332
Monopole transitions from the 01+ ground states to 02+ excited states at 3.353 MeV (40Ca), 1.837 MeV (42Ca), 1.884 MeV (44Ca) and 4.272 MeV (48Ca) have been investigated with high resolution inelastic electron scattering (FWHM ≈ 30 keV) at low momentum transfer (0.29 ≦ q ≦ 0.53 fm?1). The respective monopole matrix elements are 2.53 ± 0.41 fm2, 5.24 ± 0.39 fm2, 5.45 ± 0.41 fm2 and 2.28 ± 0.49 fm2. These results are used together with known ground state charge radii and the average number of holes in the sd shell in the ground state to estimate the number of particle-hole excitations in the wave functions of the excited 0+ states. 相似文献