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1.
The isobaric analog resonances in 53Mn with different spins and parities are investigated by means of the 52Cr(p, p), (p, p′), (p, p′γ), and (p, γ) reactions. Spectroscopic factors are derived and the experimental (p, γ) strengths are compared with theoretical single-particle estimations.  相似文献   

2.
Differential cross sections for the elastic and inelastic scattering of 14.1 MeV neutrons from 209Bi have been measured with a time-of-flight system which had an energy resolution of 650 keV. For elastic scattering from 209Bi, an optical-model analysis gave the best-fit potential parameters. The absolute cross sections for excitation of collective (2.66 and 4.36 MeV) states are reproduced by the results of distorted-wave calculations under the assumption of a core (208Pb) excitation model using deformation parameters obtained from (p, p') reactions.  相似文献   

3.
In this paper we study within the Dyson boson expansion (DBE) the particle-vibration coupling in 209Bi as a function of the number of configurations one is taking into account (vertical convergence). We find that the energies converge quite rapidly but that it is somewhat more difficult to achieve convergence also for the transition probabilities. We essentially investigate the well-known septuplet and decuplet in 209Bi and find reasonable agreement with experiment.  相似文献   

4.
Differential cross-section and analysing-power excitation functions were measured for elastic proton scattering from Ep = 3.6–6.4 MeV at θc.m. = 90°, 115.8°, 129.8° and 155.3°. Differential cross-section angular distributions were measured at 3.56, 3.94, 5.78 and 8.98 MeV and analysing-power angular distributions at 5.78 and 8.98 MeV. Optical-model parameters were deduced from these distributions. Resonance parameters were determined for eight analogue resonances in 71Ga and neutron spectroscopic factors were calculated. These were compared with the results of previous (p, p) cross-section analyses and the results of (d, p) reactions leading to states in 71Zn.  相似文献   

5.
The g-factors of the 10? isomeric states in 202Bi and 204Bi have been measured by the method of in-beam TDPAD. The experimental values g = 0.243(14) for202Biand g = 0.236(23) for204Bi confirm the previously suggested shell-model configuration.  相似文献   

6.
Excitation functions for elastic and inelastic scattering of protons from 110Cd and 112Cd have been measured in the energy ranges of 5.8–8.1 MeV in 110Cd and 6.1–8.4 MeV in 112Cd. Elastic resonance data have been analyzed using the many-level formula of modified R-matrix theory. Angular distributions have been measured at four prominent inelastic resonances- The results are compared with spectroscopic predictions deduced from calculations using the quasiparticle randomphase approximation (QRPA). The contributions of two different modes arising from the 2p-1h character of the analog state and from the particle-core coupling nature of the parent state were deduced in a microscopic picture. The interference between the resonance and direct scattering has a marked effect on the inelastic angular distributions.  相似文献   

7.
The 96Zr(τ, α)95Zr reaction at 39 MeV incident energy was used to populate both the low-lying and highly excited (up to an excitation energy of 18 MeV) analog states in 95Zr and some low-lying levels in other Zr isotopes. The main components of the 2d52. and 1g92. hole strengths and the analogs of the 2p12., 2p32. and 1f32. proton hole states in 95Y have been observed in this work. Angular distributions of transitions to 27 levels in 95Zr have been extracted and analysed with DWBA calculations to yield spectroscopic factors. Between the excitation energies of 1 and 3 MeV in 95Zr a number of levels with l = 2, 4 and 5 angular distributions have been identified. These are associated with the 2d32, 1g72 and 1h112 components already observed in the previous study of the 94Zr(d, p) and (α, τ) reactions. The total strength and center of gravity for levels assigned to the (1g92)?1 configurations in 95Zr are presented and compared to the results obtained from the studies of neutron pick-up reaction on 91Zr and 98Mo. For the isobaric analog states observed between the excitation energies of 15 and 17 MeV, total widths, Coulomb displacement energies and spectroscopic factors are also determined from this experiment and the results compared with the properties of the low-lying proton hole states in the 95Y parent nucleus.  相似文献   

8.
A high-accuracy investigation of absolute γ-ray yields and angular distributions after Coulomb excitation of 203Tl, 205Tl and 209Bi allowed the determination of B(E2) and B(M1) values in these nuclei. Some of the data obtained are compared with direct lifetime measurements and internal conversion data. The influence of deorientation effects on our results is discussed. A comparison is made between the experimental transition matrix elements and shell-model and core-coupling-model calculations. The “l-forbidden” M1 transitions, which are caused by core-polarization effects, have strengths of ≈ 10?3 W.u. In 209Bi the strength of the f72h92. E2 transition is equivalent to a surprisingly large proton polarization charge of (2.8 ± 0.2)e.  相似文献   

9.
Excitation functions and ranges of recoil nuclei in the 209Bi(p, 3n)207Po, 209Bi(p, 4n) 206Po and 209Bi(p, p3n)206Bi reactions have been measured for incident energies from 18 MeV up to 52 MeV. It has been found that the recoil ranges in (p, p3n) reactions are rather shorter than those in (p, 4n), and that beyond Ep = 40 MeV the high energy tail of the excitation function for (p, p3n) is roughly flat, in contrast to the decreasing tail for (p, 4n). A theoretical analysis of the excitation functions and of the nuclear recoil ranges has been made. It has been found that in (p, p3n) reactions the direct process plays a very important part in the reaction mechanism. It is also found that the reaction mechanisms of (p, 3n) and (p, 4n) reactions should be interpreted by means of an admixture of the equilibrium compound process and the pre-equilibrium decay process at bombarding energies up to 40 MeV and 50 MeV, respectively, and that the direct process seems to appear at bombarding energies higher than these respective energies.  相似文献   

10.
The dependence of the in-plane and out-of-plane angular correlations of fragments from fissioning heavy products on the kinetic energy and Z of the light reaction partner have been measured. From the dependence of the angular correlations on Q-value and hence energy loss, together with existing data from which the total angle-integrated cross section as a function of energy loss can be extracted, we have determined the dependence of the angular momentum transferred to the heavy product on the initial orbital angular momentum or impact parameter. The resulting dependence is qualitatively consistent with the sticking limit for a reaction intermediate of touching deformed fragments. More specific nuclear models generally underestimate the angular momentum transfer, although the one-body proximity-friction model accounts for the major fraction of the angular momentum transfer. A recent model incorporating both one-body proximity friction and collective excitations accounts quite well for the observed angular momentum transfer. The Z-dependendence of the anisotropy shows the importance of angular momentum fractionation for the less probable events, where the Z of the fissioning system is appreciably less than that of the target. The transferred angular momentum is shown to be fairly strongly aligned along the perpendicular to the reaction plane, with alignment values of 0.6 to 0.8. The component of angular momentum not along the perpendicular to the reaction plane is found to be primarily oriented perpendicular rather than parallel to the recoil direction. The absolute fission probabilities are found to be qualitatively consistent with J-dependent calculations using the J-values deduced from the angular correlations.  相似文献   

11.
A 90° photoproton energy spectrum has been obtained from the reaction 90Zr(γ, p)89Y using an isotopically enriched target foil. Previously unreported proton groups are observed at Ep = 6.95, 9.55, 10.68 and 11.03 MeV. A total photoneutron cross section and a low-energy neutron energy spectrum are also presented, and isospin mixing is demonstrated by comparison with the photoproton data. The possibility of T> strength in the region 23–24 MeV excitation is noted.  相似文献   

12.
Fission of 232Th, 237Np, 209Bi, 235U and 238U induced by 110 MeV electrons has been studied by means of surface barrier detectors. The resulting mass and kinetic energy distributions are presented. Comparison with the liquid drop model predictions shows reasonable agreement in the case of 209Bi. The data are analysed in terms of a two component model of fission and the mean total kinetic energies of the components are shown to depend linearly on Z1Z2(A113 + A213). Interesting differences are found when the present results are compared with the recent photofission experiments of Areskoug et al. and features in both sets of data correlate with changes of fragment deformation implied by the calculations of Wilkins et al.  相似文献   

13.
Low-lying states in 83Se have been studied through proton-induced isobaric analog resonance (IAR) reactions. Excitation functions for elastic and inelastic proton scattering were measured in the bombarding energy range 4.5– to 7.7 MeV. Angular distributions of proton inelastic scattering cross sections for the reaction 82Se(p, p')82Se(0.655 MeV 2+) and angular correlations of the inelastic protons and the associated 2+-0+ de-excitation γ-rays were measured on observed resonance peaks. In the analysis for the inelastic scattering, direct reaction contributions to the IAR were taken into account. Correlations between the low-lying states in 83Se and the excited 2+ core state are discussed.  相似文献   

14.
Excitation functions of proton elastic and inelastic scattering from 74Se were measured to investigate the isobaric analogue resonances (IAR) in 75Br. Observed IAR correspond to the parent states of 75Se in excitation energy from 0.29 to 1.8 MeV. For eleven resonances, resonance parameters were determined from the analysis of the elastic scattering. For three of these resonances, inelastic widths to the 2+ (0.635 MeV) state in 74Se were obtained from the analysis of the angular distributions of inelastically scattered protons. Spectroscopic factors obtained from the elastic scattering were compared with those from the 74Se(d, p)75Se reaction. There is good agreement between the corresponding Spectroscopic factors except for the states with ln = 1 where they were much smaller than the (d, p) ones. For the inelastic scattering, it was proved that the compound process via IAR play an important role and the analysis including the compound process explained the experimental results reasonably well.  相似文献   

15.
An experimental study of inelastic scattering of polarized protons from 126Te, leaving this nucleus in its first excited state, is presented. The scattering proceeds through isobaric analogue resonances in 127I.A method has been developed and applied to extract partial width amplitudes from measured cross sections and analyzing powers. From these amplitudes coefficients of fractional parentage are deduced, characterizing the relation between five negative parity parent states in 127Te and the first excited state of 126Te.  相似文献   

16.
The γ-decay of excited states in 210Bi up to 3330 keV excitation energy has been studied using the 209Bi(d, pγ)210Bi reaction. From the observed decay scheme, tentative Jπ values are made for 25 states. The excitation energies, (d, p) strengths and decay branching ratios of these states are compared with those calculated using the two-particle shell-model wave functions of Kim and Rasmussen and Kuo and Herling.  相似文献   

17.
18.
Mean lifetimes of levels in 18F have been measured using the Doppler-shift attenuation method and the inverse reaction 3He(16O, p)18F. Targets of 3He implanted into Al, Nb, and Au foils were employed in the measurements. The Doppler-broadened lineshapes observed at 0° to the beam were analyzed to obtain the following lifetime values: 0.971 ± 0.030, 0.605 ± 0.029 and 0.435 ± 0.041 ps for the 1.70(1+), 2.52(2+) and 3.36(3+)MeV members of the Kπ = 1+ rotational band, 5.12 ± 0.56, 0.403 ± 0.018 and 1.91 ± 0.17 ps for the 2.10(2?), 3.13(1?) and 3.79(3?) MeV members of the Kπ = 0? bands, and 〈1.2, 2.7+4.1?2.7 and 20 ± 2 fs for the 3.06(2+, T = 1), 3.72(1+) and 3.84(2+) MeV states, respectively.  相似文献   

19.
Differential cross section and analyzing power angular distributions have been measured for transitions to low-lying bound states with Jπ = 2+, 3?, 4+ and 5?, and the giant resonance region from 6 to 27 MeV excitation energy. Collective model calculations using a full Thomas form factor reproduce the data fairly well. The so-called LEOR turns out not to be seen as pure E3 in (p, p′). In the giant resonance region the data do not reveal the presence of a sizeable monopole strength, 10–20% of the energy-weighted sum rule at most. There is strong indication for a mixture of E2 (18% of the EWSR) and E4 (16% of the EWSR). Calculations were also carried out using RPA (1p1h) wave functions. They reproduce the experimental data rather poorly, except for the general behaviour of the cross-section angular distributions.  相似文献   

20.
Reactions of 40Ar ions with targets of 159Tb, 142Nd, and 144Sm have been studied at energies below 300 MeV with a helium gas-jet system. Excitation functions for (Ar, xn) reactions, where x = 5–10, were obtained for the radioactive products that decay by α-emission. Based on the characteristics of these excitation functions and on the systematics of α-decay, evidence is presented for the existence of the nuclides 189Bi with α-particle energy Eα = 6.67±0.01 MeV and half-life < 1.5 sec, and 173Pt with Eα = 6.19±0.01 MeV; and for the emission from 177Au of an α-particle with Eα = 6.15±0.01 MeV.  相似文献   

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