共查询到20条相似文献,搜索用时 31 毫秒
1.
A. A. Kulko N. A. Demekhina R. Kalpakchieva Yu. A. Muzychka Yu. E. Penionzhkevich D. N. Rassadov N. K. Skobelev D. A. Testov 《Physics of Atomic Nuclei》2007,70(4):613-618
Excitation functions are measured for the fusion reactions 197Au(4He, xn)201?xn Tl that are induced by alpha-particle interaction with gold nuclei in the energy range 14–36 MeV and in which x neutrons (0 ≤ x ≤ 3) are evaporated. The stack-activation technique was used to record and separate reaction products. Experimental data on the fusion reactions followed by evaporation of one to three neutrons agree with results of previous studies. For the radiative-capture reaction 197Au(4He,γ)201Tl, the upper limit on the cross section proved to be much lower. The excitation functions for the reactions subjected to measurements are compared with the results of calculations based on the statistical model and with the results of an experiment performed previously in a 6He beam. 相似文献
2.
M. A. Naumenko V. V. Samarin Yu. E. Penionzhkevich N. K. Skobelev 《Bulletin of the Russian Academy of Sciences: Physics》2017,81(6):710-716
Experimental cross sections of formation of isotopes 46Sc (in reaction 6He + 45Sc), 196,198Au (in reaction 6He + 197Au), and 65Zn (in reaction 6He + 64Zn) are analyzed. The time-dependent Schrödinger equation for the outer neutrons of 6He and 197Au nuclei is solved numerically to calculate the probability of neutron transfer and transfer cross sections. In reaction 6He + 197Au, the contribution of fusion and subsequent evaporation to experimental data can be neglected, while the corresponding contributions to reactions 6He + 45Sc and 6He + 64Zn are considerable. Fusion–evaporation is taken into account using the computational code of the NRV knowledge base. The results of calculations are in satisfactory agreement with the experimental data. 相似文献
3.
Zh. A. Asanov A. N. Ermakov B. S. Ishkhanov I. M. Kapitonov Kyaw Kyaw Htun I. V. Makarenko D. R. Salakhutdinov V. A. Chetvertkova 《Bulletin of the Russian Academy of Sciences: Physics》2007,71(3):332-335
The thallium isotopes 203Tl and 205Tl were irradiated using a beam of bremsstrahlung gamma quanta with the maximum energy E γ m = 50 MeV from an RTM-70 electron racetrack microtron installed at the Scobeltsyn Nuclear Physics Research Institute (Lomonosov Moscow State University, Russia). The gamma spectra of the residual activity were measured for an irradiated sample. Photonuclear reactions in the 203Tl nuclei with emission from one to four neutrons were observed experimentally. The relative yields of the reactions 203Tl(γ,n)202Tl, 203Tl(γ,2n)201Tl, 203Tl(γ,3n)200Tl, and 203Tl(γ,4n)199Tl were determined for the first time. 相似文献
4.
G. L. Bayatyan G. S. Vartanyan N. K. Grigoryan S. G. Knyazyan V. P. Likhachev A. T. Margaryan G. G. Marikyan T. A. Rostomyan 《Physics of Atomic Nuclei》2002,65(8):1474-1478
New experimental data are presented that were obtained by studying the multifragmentation of 197Au, 209Bi, 238U, and 243Am nuclei in a coherent bremsstrahlung-photon beam with an endpoint energy of 4.1 GeV from the Erevan Synchrotron. For the first time, four or more fragments are observed. For all the nuclei studied here, the respective production cross sections are about (1–3)×10?3 of the total inelastic photon-nucleus cross section. The fragment yields are isotropic. 相似文献
5.
N. K. Skobelev Yu. E. Penionzhkevich A. A. Kulko N. A. Demekhina V. Kroha A. Kugler S. M. Lukyanov J. Mrazek Yu. G. Sobolev V. A. Maslov Yu. A. Muzychka E. I. Voskoboynik A. S. Fomichev 《Physics of Particles and Nuclei Letters》2013,10(3):248-255
New data on the cross sections of reactions occurring during the interaction of 6He nuclei with 197Au at energies of 6He from 40 to 120 MeV are presented. The experiments were performed in the ACCULINNA secondary beam separator of the Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research. To identify the reaction products, the activation method for measuring the gamma activity of the target assembly of thin foils was used. The excitation functions for fusion reactions involving the evaporation of up to ten neutrons from the compound nucleus as well as reactions with the emission of charged particles and nucleon transfer in the investigated energy region are obtained. Data analysis was carried out using two codes: ALICE-MP and NRV. The cross sections for the (6He, xn) reactions occurring through the compound nucleus are mostly in agreement with the results of model calculations based on the statistical approach. It is shown that, up to the energies of 114 MeV, the cross-section drop in the complete fusion reactions is negligible. The experimental excitation functions of reactions leading to the formation of isotopes of mercury and gold (transfer reaction) indicate that the main contribution to their formation is made by direct processes and that evaporation reactions (6He, pxn) and (6He, αxn) play a minor role, as is evidenced by a comparison of the measured cross sections with the calculation results. 相似文献
6.
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
7.
M. A. Naumenko V. V. Samarin Yu. E. Penionzhkevich N. K. Skobelev 《Bulletin of the Russian Academy of Sciences: Physics》2016,80(3):264-272
Experimental cross sections for the formation of 196,198Au isotopes in the 3He + 197Au reaction and 44,46Sc isotopes in the 3He + 45Sc reaction are analyzed. To calculate transfer probabilities and cross sections, the time-dependent Schrödinger equation is numerically solved for the external neutrons of the 3He, 45Sc, and 197Au nuclei. It is shown that the contribution from the fusion channel with subsequent evaporation is important for the 3He + 45Sc reaction and negligibly small for the 3He + 197Au reaction. Fusion–evaporation is taken into account using the NRV and PACE codes. Calculation results demonstrate overall satisfactory agreement with experimental data. 相似文献
8.
An experiment on the irradiation of the natural mixture of 203,205Tl isotopes by the bremsstrahlung beam of pulsed racetrack microtron RTM-70 (Skobeltsyn Institute of Nuclear Physics, Moscow State University) at an electron energy of 67.7 MeV was performed. The yields and integral cross sections of multiparticle photonuclear reactions with 203,205Tl isotopes were measured. 相似文献
9.
A. R. Balabekyan G. S. Karapetyan N. A. Demekhina J. Adam K. Katovsky 《Physics of Atomic Nuclei》2010,73(11):1814-1819
Fission product cross sections of intermediate-energy fission of 238U were used in order to construct the charge and mass yield distributions. Enriched target of 238U was irradiated by proton beam with energy 660 MeV for several hours at the LNP Phasotron, Joint Institute for Nuclear Research
(JINR), Dubna, Russia. The charge distribution of the fission fragments was analyzed for calculation of isobaric cross sections.
The mass yield curves were expanded into symmetric and asymmetric components according multimodal fission approach. The fissility
values of actinides were calculated at given proton energy. The obtained results have been compared to the same data for targets
237Np and 241Am. 相似文献
10.
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
11.
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
12.
Yu. E. Penionzhkevich Yu. G. Sobolev V. V. Samarin M. A. Naumenko 《Physics of Atomic Nuclei》2017,80(5):928-941
The energy dependence of the total cross sections for the 6He + Si and 9Li + Si reactions was measured at beam energies between 5 and 20 MeV per nucleon. The results agree with experimental data published for the 6He + Si reaction. New data are obtained for the 9Li + Si reaction in the vicinity of a local enhancement of the total cross section. A theoretical analysis of the possible reasons behind the appearance of this peculiarity in the case of collisions of 6He and 9Li nuclei with silicon target nuclei is performed. In particular, the enhancement may owe its origin to the effect of loosely bound projectile nucleons. 相似文献
13.
The differential cross sections for p 10B scattering are calculated at the energies of 197, 600, and 1000 MeV within Glauber theory. The contributions of single and double collisions are taken into account in the multiple-scattering operator. The contributions of proton collisions with nucleons belonging to various (1s, 1p) shells are estimated in the single-scattering cross sections. A comparison with experimental data and with the result of calculations in the distorted-wave Born approximation (DWBA) at 197 MeV showed that the differential cross sections for p 10B scattering are adequately described in the region forward scattering angles. 相似文献
14.
V. V. Samarin Yu. E. Penionzhkevich M. A. Naumenko N. K. Skobelev 《Bulletin of the Russian Academy of Sciences: Physics》2018,82(6):637-642
Calculations of production cross sections for isotopes 194Au in the 3He + 194Pt reaction and 45Ti in the 3He + 45Sc reaction are performed, based on the solution to a time-dependent Schrödinger equation in combination with calculations in the statistical model using the computational code of the NRV data base. The experimental differences in the near-barrier energy dependences of the isotope production cross sections in these reactions are explained by the difference between the proton and neutron shells of the target nuclei, and by the different evolutions of the probability density for protons of the projectile nucleus and neutrons of the target nuclei in collisions. 相似文献
15.
A. N. Ermakov B. S. Ishkhanov I. M. Kapitonov Kyaw Kyaw Htun I. V. Makarenko 《Moscow University Physics Bulletin》2007,62(5):316-319
An experiment on irradiation of the 197Au isotope by a beam of bremsstrahlung γ-rays of maximum energy E γ m = 70 MeV has been carried out at the RTM-70 race-track microtron of the INP MSU. Residual activity spectra of the irradiated sample were measured. Multiparticle photonuclear reactions on the 197Au nucleus are observed. Photonuclear reactions with emission of as many as six neutrons are observed for the first time. 相似文献
16.
The breakup reactions of 8B on a 12C target at 142, 285, 790, and 936MeV/nucleon have been studied. One-proton-removal cross sections, leading to the production of 7Be fragments in the ground and first excited states (at 0.429MeV), and the longitudinal momentum distributions of the 7Be fragments are obtained in the Eikonal approximation of the Glauber Model. The results of the calculations including the contribution of the 7Be to the ground and first excited states of 8B are compared with the available experimental data. One-proton-removal cross section for the 12C(8B, 7Be)X knockout reaction at 142, 285, 790, and 936 MeV/nucleon energy has been calculated. 8B and 7Be cross sections and momentum distribution are in a good agreement with available data. 相似文献
17.
K. B. Gikal E. M. Kozulin A. A. Bogachev N. T. Burtebaev A. V. Edomskiy I. M. Itkis M. G. Itkis G. N. Knyazhev K. V. Kovalchuk T. N. Kvochkina E. Piasecki V. A. Rubchenya S. K. Sahiev W. H. Trzaska E. Vardaci 《Physics of Atomic Nuclei》2016,79(9-10):1367-1374
The mass-energy distributions and cross sections of proton-induced fission of 232Th have been measured at the proton energies of 7, 10, 13, 20, 40, and 55 MeV. Experiments were carried out at the proton beam of the K-130 cyclotron of the JYFL Accelerator Laboratory of the University of Jyväskylä and U-150m cyclotron of the Institute of Nuclear Physics, Ministry of Energy of the Republic of Kazakhstan. The yields of fission fragments in the mass range A = 60–170 a.m.u. have been measured up to the level of 10?4%. The three humped shape of the mass distribution up has been observed at higher proton energies. The contribution of the symmetric component grows up with increasing proton incident energy; although even at 55 MeV of proton energy the shoulders in the mass energy distribution clearly indicate the asymmetric fission peaks. Evolution of shell structure was observed in the fission fragment mass distributions even at high excitation energy. 相似文献
18.
Yu. A. Glukhov A. A. Ogloblin K. P. Artemov V. P. Rudakov 《Physics of Atomic Nuclei》2010,73(1):14-23
A systematic investigation of the elastic scattering of the 9Be nucleus, which is among themost loosely bound stable nuclei was performed.Differential cross sections for elastic 9Be + 16O scattering were measured at a c.m. energy of 47.5 MeV (beam of 132-MeV 16O nuclei). Available data at different energy values and data for neighboring nuclei were included in our analysis. As a result,
the very fact of rainbow scattering was reliably established for the first time in systems involving 9Be. In addition, the analysis in question made it possible to identify Airy minima and to determine unambiguously the nucleus-nucleus
potential with a high probability. 相似文献
19.
A. Ya. Rusanov M. G. Itkis N. A. Kondratiev I. V. Pokrovsky V. S. Salamatin G. G. Chubarian 《Physics of Atomic Nuclei》2007,70(10):1669-1678
Correlations between folding angular distributions of fission fragments and the gamma-ray multiplicity are studied for 18O + 208Pb interactions at energies of the beam of 18O ions in the range E lab = 78–198.5 MeV. The probabilities are determined for complete-and incomplete-fusion processes inevitably followed by the fission of nuclei formed in these processes. It is found that the probability of incomplete fusion followed by fission increases with increasing energy of bombarding ions. It is shown that, for the incomplete-fusion process, folding angular distributions of fission fragments have a two-component structure. The width of folding angular distributions (FWHM) for complete fusion grows linearly with increasing energy of 18O ions. The multiplicity of gamma rays from fission fragments as a function of the linear-momentum transfer behaves differently for different energies of projectile ions. This circumstance is explained here by the distinction between the average angular momenta of participant nuclei in the fusion and fission channels, which is due to the difference in the probabilities of fission in the cases where different numbers of nucleons are captured by the target nucleus. 相似文献
20.
V. I. Kovalchuk 《Physics of Atomic Nuclei》2016,79(3):335-341
A microscopic formalism for describing observed cross sections for deuteron breakup by threenucleon nuclei was developed on the basis of the diffraction nuclear model. A general formula that describes the amplitude for the reaction 2H(3He, 3Hep)n and which involves only one adjustable parameter was obtained by using expansions of the integrands involved in terms of a Gaussian basis. This formula was used to analyze experimental data on the exclusive cross sections for deuteron breakup by 3He nuclei at the projectile energy of 89.4MeV. The importance of employing, in calculations, a deuteron wave function that has a correct asymptotic behavior at large nucleon–nucleon distances was demonstrated. 相似文献