共查询到20条相似文献,搜索用时 62 毫秒
1.
I. N. Vishnevsky O. I. Davidovskaya V. A. Zheltonozhsky A. N. Savrasov 《Bulletin of the Russian Academy of Sciences: Physics》2009,73(6):733-736
The average angular momenta of the 84Br, 132Sb, 133Te, and 135Xe fission fragments, produced as a result of 232Th and 238U photofission by bremmsstrahlung γ photons with an endpoint energy of 8.5 MeV, have been determined by measuring the isomeric yield ratios. The experimental isomeric yield ratios have been calculated taking into account the contribution from β decay of isobaric nuclei to the yields of isotopes studied. 相似文献
2.
I. N. Vishnevskii O. I. Davidovskaya V. A. Zheltonozhskii A. N. Savrasov 《Bulletin of the Russian Academy of Sciences: Physics》2010,74(4):500-503
Average angular momenta of fission fragments 90Rb, 129,130,132Sb, 131,133Te, 134,136I, and 135Xe produced in photofission of 235U and 239Pu by bremsstrahlung γ rays with a threshold energy of 9.6 and 9.8 MeV, respectively, were determined by measuring the isomeric
yield ratios. The experimental values of the isomeric ratios were calculated with account of the contribution from β decay
of isobaric nuclei in the yields of the studied isotopes. 相似文献
3.
Observables of the elastic and inelastic scattering of 800- and 250-MeV protons on 20Ne and 24Mg nuclei were calculated on the basis of the theory of multiple diffractive scattering and the dispersive α-cluster model. The 20Ne and 24Mg nuclei were assumed to consist of a core (16O nucleus) and additional alpha-particle clusters, which could be situated with the highest probability both in the vicinity
of the center of mass of the core and outside the core. The multiparticle densities of these nuclei and single-particle nucleon-distribution
densities as obtained from the dispersive α-cluster model were used in the calculations. The differential cross sections and polarizations for elastic and inelastic
p
20Ne and p
24Mg scattering at the energy of 800 MeV are in better agreement with experimental data than the analogous calculations at the
energy of 250 MeV. The spin-rotation functions calculated in the singleparticle approximation for elastic p
20Ne and p
24Mg scattering at these two energy values differ qualitatively from their counterparts calculated on the basis of the dispersive
α-cluster model. 相似文献
4.
A.?A.?Kuliev E.?Guliyev F.?Ertugral S.??zkan 《The European Physical Journal A - Hadrons and Nuclei》2010,43(3):313-321
In this study, Ip = 1+\ensuremath I^{\pi} = 1^{+} and Ip = 1-\ensuremath I^{\pi} = 1^{-} dipole mode excitations are systematically investigated within the rotational and translational + Galilean invariant quasiparticle
random-phase approximation for 232Th , 236U , and 238U actinide nuclei. It is shown that the investigated nuclei reach a B(M1) strength structure, which corresponds to the scissors mode. The calculated mean excitation energies as well as the summed
B(M1) value of the scissors mode excitations are consistent with the available experimental data. The results of calculations
indicate large differences to the rare-earth nuclei as is the case for the experiment: a doubling of the observed dipole strengths
and a shift of the energy centroid to the lower energies by about 800keV. The calculations indicate the presence of a few
prominent negative-parity Kp = 1-\ensuremath K^{\pi} = 1^{-} states in the 2.0-4.0MeV energy interval. The occurrence of the negative-parity dipole states with the rather high B(E1) value less than 4MeV shows the necessity of explicit parity measurements for the correct determination of the scissors
mode strength in 232Th , 236U , and 238U isotopes. 相似文献
5.
Yu. A. Berezhnoy D. V. Fedorchenko V. P. Mikhailyuk V. V. Pilipenko 《The European Physical Journal A - Hadrons and Nuclei》2012,48(1):4
A model based on the multiple diffraction scattering theory and the α-cluster model with dispersion of target nuclei is proposed for describing the behavior of observables for the elastic deuteron
scattering from 12C and 16O nuclei at intermediate energies. Differential cross-sections and analyzing powers calculated within this approach for incident-deuteron
energies of 400 and 700 MeV are in a reasonable agreement with experimental data. 相似文献
6.
Coupled-channels calculations for the elastic and inelastic scattering of K+ at 715 MeV/c by 6Li and 12C at 635, 715 and 800 kaon Lab momenta have been analysed. The optical potentials of 12C and 6Li are calculated in terms of the alpha-particle and deuteron optical potentials. Good fits to the experimental data and phenomenological
calculations are obtained for 6Li and 12C nuclei. 相似文献
7.
V. I. Kovalchuk 《Physics of Atomic Nuclei》2009,72(8):1247-1252
A theory of the diffractive scattering of loosely bound three-cluster nuclei by nuclei was developed with allowance for Coulomb interaction. The differential cross sections for the scattering of projectile exotic nuclei 7Be and 8B by 12C nuclei at an energy of 40 MeV per nucleon were calculated within the proposed formalism. The results describe satisfactorily relevant experimental data. 相似文献
8.
A theory is developed for describing the diffractive dissociation of loosely bound two-cluster nuclei in the nuclear and Coulomb fields of nuclei having a diffuse boundary. The energy spectra of charged products of the breakup of 2H, 6He, and 19C nuclei are calculated on the basis of the proposed approach, and the results are found to be rather sensitive to nuclear structure. For some angles of neutron and proton emission from the reaction 12C(d, np)12C, the calculated cross sections are in satisfactory agreement with the results of kinematically complete experiments performed recently to study the breakup of intermediate-energy deuterons. 相似文献
9.
Shen Shuifa Fang Keming Gu Jiahui Liu Qingcheng Xu Furong 《The European Physical Journal A - Hadrons and Nuclei》2007,32(2):149-158
The decay of 95Ru has been investigated by means of γ-ray spectroscopy. The 95Ru nuclei were produced by the reaction 92Mo( α, n) 95Ru at a beam energy of 17MeV. High-purity Ge detectors have been used singly and in coincidence to study γ-rays in the decay of 95Ru to 95Tc. 132 γ-rays are reported, among them, energies and intensities for 127 transitions have been determined. A decay scheme of 95Ru with 31 levels is proposed which accommodates 127 of these transitions. Spins and parities for three new levels are proposed
from calculated log ft values, measured γ-ray branching ratios, and in-beam experiment results of the daughter nucleus 95Tc. Combining with the high-spin states observed by in-beam γ-ray spectroscopy of previous decay works, the structure of the excited states of 95Tc is discussed in the framework of the projected shell model. 相似文献
10.
The configuration-dependent cranked Nilsson-Strutinsky approach has been employed to study the properties and band structures
at high spin in the Z = N odd-odd nuclei 46V and 50Mn. The observed bands are explained and terminating states are confirmed by the calculations. The calculated and observed
bands are in good agreement without normalization, especially for terminating states. Possible bands with rotation around
the intermediate axis and the effect of γ-deformation on the total energy of several interesting configurations are discussed.
Received: 2 April 2002 / Accepted: 27 January 2003 / Published online: 15 April 2003 相似文献
11.
The excitation functions for both the evaporation residue and fission have been calculated for 10B + 209Bi and 11B + 209Bi reactions forming compound systems 219, 220Ra* , using the dynamical cluster-decay model (DCM) with effects of deformations and orientations of the nuclei included in it.
In addition to this, the excitation functions for complete fusion (CF) are obtained by summing the fission cross-sections,
neutron evaporation and charged particle evaporation residue cross-sections produced through the axn\ensuremath \alpha xn and pxn\ensuremath pxn (x = 2, 3, 4) emission channels for the 219Ra system at various incident centre-of-mass energies. Experimentally the CF cross-sections are suppressed and the observed
suppression is attributed to the low binding energy of 10, 11B which breaks up into charged fragments. The reported complete fusion (CF) and incomplete fusion (ICF) excitation functions
for the 219Ra system are found to be nicely fitted by the calculations performed in the framework of DCM, without invoking a significant
contribution from quasi-fission. Although DCM has been applied for a number of compound nucleus decay studies in the recent
past, the same is being used here in reference to ICF and subsequent decay processes along with the CF process. Interestingly
the main contribution to complete fusion cross-section comes from the fission cross-section at higher incident energies, which
in DCM is found to consist of an asymmetric fission window, shown to arise due to the deformation and orientation effects
of formation and decay fragments. 相似文献
12.
Yu. P. Gangrsky V. I. Zhemenik N. N. Kolesnikov V. G. Lukashik B. N. Markov G. V. Myshinskiy O. D. Maslov G. A. Bozhikov 《Physics of Atomic Nuclei》2010,73(9):1477-1481
The yields of 135Cs nuclei in a high-spin (19/2) isomeric state and of nuclei neighboring it were measured for photonuclear reactions of the
(γ, f) and (γ, α) types. The experiments in question were performed by using bremsstrahlung from a microtron at the maximum electron energy
of 25 MeV. The product nuclei were identified by their half-lives and by the lines of gamma radiation emitted in their decay,
and the reaction yields R were determined by the ratios of the intensities of these lines to the bremsstrahlung flux. The cross sections for isomer
production were calculated, and the angular momenta of product nuclei immediately before the cascade of gamma transitions
populating the ground or an isomeric nuclear state were evaluated on the basis of these results. An enhanced yield of the
high-spin isomer of 135Cs in the fission reaction in relation to the respective (γ, α) reaction and in relation to the results of the calculations is found. 相似文献
13.
M. A. Zhusupov A. Yu. Zaikin E. T. Ibraeva Sh. Sh. Sagindykov 《Bulletin of the Russian Academy of Sciences: Physics》2008,72(7):1013-1018
The differential cross sections of proton elastic scattering from 8Li and 9Li nuclei in inverse kinematics have been calculated. The cross sections were determined within the Glauber diffraction theory
with the wave functions of nuclei in the three-particle α-t-n, α-t-2n, and 7Li-n-n models. Comparison with the existing experimental data for E = 700 and 60 MeV/nucleon made it possible to draw a conclusion about the quality of the wave functions and the adequacy of
the potentials used for their calculations. 相似文献
14.
N. G. Peresadko Yu. A. Alexandrov S. G. Gerasimov V. A. Dronov V. G. Larionova A. V. Pisetskaya E. I. Tamm V. N. Fetisov S. P. Kharlamov L. N. Shesterkina 《Physics of Atomic Nuclei》2010,73(11):1942-1947
In a track nuclear photoemulsion exposed to a beam of 7Li nuclei accelerated to a momentum of 3 GeV/c per nucleon at the synchrophasotron of the Joint Institute for Nuclear Research (JINR, Dubna), 13 events in which 7Li nuclei interacting with protons break up into 3H and 4He fragments were detected among 3730 inelastic-interaction events. For this fragmentation channel, the cross section was
found to be 8 ± 2 mb. The average value of the fragment total transverse momentum was 214 ± 5 MeV/c. This value exceeds markedly the average value of the transverse-momentum transfer in the coherent dissociation of 7Li nuclei on track-emulsion nuclei (166±5MeV/c). The recoil-proton transverse momentum was on average 98% of the total proton momentum. The longitudinal-momentum distribution
of protons was characterized by a variance of 16 MeV/c and a mean value of 37 ± 2MeV/c. 相似文献
15.
E. T. Ibraeva N. T. Burtebaev P. M. Krassovitskiy 《Bulletin of the Russian Academy of Sciences: Physics》2016,80(3):258-263
Differential cross sections of the elastic scattering of protons of intermediate energies by 9B and 10B nuclei are calculated within the Glauber theory. The matrix elements of elastic scattering are derived with a wave function in the three-particle 2αp-model (for 9B) and with an oscillatory wave function (for 10B). The differential cross-sections are calculated with allowance for the triple collisions on 9B nuclei and in the approximation of double collisions on 10B nuclei. The sensitivity of the differential cross-section to the 9B nucleus structure is analyzed. The differential cross section of 10B at E = 197 MeV is compared to the results from calculations using the distorted wave method. 相似文献
16.
S. Singh R. Chandra P. K. Rath P. K. Raina J. G. Hirsch 《The European Physical Journal A - Hadrons and Nuclei》2007,33(4):375-388
The two-neutrino double-beta decay of 124, 126Xe , 128, 130Te , 130, 132Ba and 150Nd isotopes is studied in the Projected Hartree-Fock-Bogoliubov (PHFB) model. Theoretical 2ν β-β- half-lives of 128, 130Te , and 150Nd isotopes, and 2ν β+β+ , 2ν β+
EC and 2ν ECEC for 124, 126Xe and 130, 132Ba nuclei are presented. Calculated quadrupolar transition probabilities B(E2 : 0+ → 2+) , static quadrupole moments and g -factors in the parent and daughter nuclei reproduce the experimental information, validating the reliability of the model
wave functions. The anticorrelation between nuclear deformation and the nuclear transition matrix element M
2ν is confirmed. 相似文献
17.
N. Turkan 《Physics of Atomic Nuclei》2010,73(1):64-73
It was pointed out that the level scheme of the transitional nuclei 124,126,128,130,132,134,136Ba also can be studied by both characteristics (IBM-1 and IBM-2) of the interacting boson model and an adequate point of the
model leading to E2 transitions is therefore confirmed. Most of the δ(E2/M1) ratios that are still not known so far are stated and the set of parameters used in these calculations is the best approximation
that has been carried out so far. It has turned out that the interacting boson approximation is fairly reliable for the calculation
of spectra in the entire set of 124,126,128,130,132,134,136Ba isotopes. 相似文献
18.
J. F. Sharpey-Schafer T. E. Madiba S. P. Bvumbi E. A. Lawrie J. J. Lawrie A. Minkova S. M. Mullins P. Papka D. G. Roux J. Timár 《The European Physical Journal A - Hadrons and Nuclei》2011,47(1):6
The concept that the first excited 0+ states in N = 90 nuclei are not a b \beta -vibration but a second vacuum formed by the combination of the quadrupole pairing force and the low density of oblate orbitals
near the Fermi surface is supported by the blocking of this collective mode in 154Gd from coupling to the [505]11/2- single-particle quasi-neutron orbital in 155Gd . The coupling of this orbital to the 2+
g \gamma -vibration in 154Gd is observed since this coupling is not Pauli-blocked. 相似文献
19.
We have calculated the potential energy surfaces forN = Z,20Ne-112Ba nuclei in an axially deformed relativistic mean field approach. A quadratic constraint scheme is applied to determine the
complete energy surface for a wide range of the quadrupole deformation. The NL3, NL-RA1 and TM1 parameter sets are used. The
phenomenon of (multiple) shape coextistence is studied and the calculated ground and excited state binding energies, quadrupole
deformation parameters and root mean square (rms) charge radii are compared with the available experimental data and other
theoretical predictions. 相似文献
20.
A. Covello L. Coraggio A. Gargano N. Itaco 《The European physical journal. Special topics》2007,150(1):93-96
We report on a study of exotic nuclei around doubly magic 132Sn in terms of the shell model employing a realistic effective interaction derived from the CD-Bonn nucleon-nucleon potential.
The short-range repulsion of the bare potential is renormalized by constructing a smooth low-momentum potential, Vlow-k, that is used directly as input for the calculation of the effective interaction. In this paper we focus attention on the
nuclei
134Sn and 135Sb which, with an N/Z ratio of 1.68 and 1.65, respectively, are at present the most exotic nuclei beyond 132Sn for which information exists on excited states.
Comparison shows that the calculated results for both nuclei are in very good agreement with the experimental data. We present
our predictions of the hitherto unknown spectrum of
136Sn. 相似文献