共查询到20条相似文献,搜索用时 15 毫秒
1.
R. Kalpakchieva V. A. Maslov R. A. Astabatian A. A. Kulko S. M. Lukyanov E. R. Markarian Yu. Ts. Oganessian Yu. E. Penionzhkevich N. K. Skobelev Yu. G. Sobolev 《Physics of Atomic Nuclei》2007,70(4):619-625
Experimental data on the momentum distributions of 4He nuclei originating from 6He and 6Li breakup on various targets are presented over a wide beam energy range. The experiment with 6He was performed at the DRIBs accelerator complex for radioactive beams at the Joint Institute for Nuclear Research (JINR, Dubna). The intensity of the 6He beam used was 5 × 106 particles per second and its energy was 10 MeV per nucleon. The momentum distributions of breakup products were measured by means of the MSP-144 magnetic spectrometer. The distribution width was shown to be virtually independent of the target mass. A small value of this width, σ ~ 28 MeV/c, confirms the presence of a halo in 6He. The measurements performed with 6Li beams of energy 18 and 46 MeV per nucleon at the U-400M accelerator yielded a width value of σ ~ 50 MeV/c for the momentum distributions of 4He nuclei, which is intermediate between that for 6He and those for stable nuclei. A compilation of the widths of the momentum distributions of fragments originating from the breakup of various nuclei is presented versus the binding energy of one or two neutrons in these nuclei, the target mass and the projectile energy. 相似文献
2.
N. G. Peresad’ko V. N. Fetisov Yu. A. Aleksandrov S. G. Gerasimov V. A. Dronov V. G. Larionova E. I. Tamm S. P. Kharlamov 《JETP Letters》2008,88(2):75-79
The differential cross section in the transverse momentum Q and a total cross section of (31 ± 4) mb for the coherent dissociation of a 3-A-Ge V/c 7Li nucleus through the 3H + 4He channel have been measured on emulsion nuclei. The observed Q dependence of the cross section is explained by the predominant supposition of the nuclear diffraction patterns on light (C, N, O) and heavy (Br, Ag) emulsion nuclei. The contributions to the cross section from nuclear diffraction (Q ≤ 400 Me V/c) and Coulomb (Q ≤ 50 Me V/c) dissociations are calculated to be 40.7 and 4 mb, respectively. 相似文献
3.
K. Olimov V. V. Glagolev S. L. Lutpullaev A. Kurbanov A. K. Olimov V. I. Petrov A. A. Yuldashev 《Physics of Atomic Nuclei》2011,74(2):268-271
Results of a comparative analysis of processes leading to the production of mirror nuclei 7Li and 7Be in 16Op collisions at a momentum of 3.25 GeV/c per nucleon are presented. A comparison of associated multiplicities of accompanying particles is performed. The first results
on the mean multiplicity of neutrons appearing as fragments are described. 相似文献
4.
Wei Jiang YanLin Ye ZhiHuan Li ChengJian Lin QiTe Li YuCheng Ge JianLing Lou DongXing Jiang Jing Li ZhengYang Tian Jun Feng Biao Yang ZaiHong Yang Jie Chen HongLiang Zang Qiang Liu PengJie Li ZhiQiang Chen Yun Zhang Yang Liu XiaoHui Sun Jing Ma HuiMing Jia XinXing Xu Lei Yang NanRu Ma LiJie Sun 《中国科学:物理学 力学 天文学(英文版)》2017,60(6):062011
A transfer-reaction experiment of 9Be(9Be, 10Be)8Be was performed at a beam energy of 45 MeV. Excited states in 10Be up to 18.80 MeV are produced using missing mass and invariant mass methods. Most of the observed high-lying resonant states, reconstructed from the α + 6He and t + 7Li decay channels, agree with the previously reported results. In addition, two new resonances at 15.6 and 18.8 MeV are identified from the present measurement. The 18.55 MeV state is found to decay into both the t + 7Lig.s. and t + 7Li* (0.478 MeV) channels, with a relative branching ratio of 0.93 ± 0.33. Further theoretical investigations are encouraged to interpret this new information on cluster structure in neutron-rich light nuclei. 相似文献
5.
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
6.
Correlations of secondary protons in 4Hep interactions are investigated in an exclusive experiment with the aid of a 2-m liquid-hydrogen bubble chamber exposed to an alpha-particle beam of momentum 5 GeV/c the kinetic energy of primary protons in the rest frame of the nucleus is Tp=620 MeV). By using data obtained in 4π geometry for six basic channels of 4Hep interaction that lead to the production of two protons, the total correlation function for the pp system is determined, along with two-proton correlation functions for individual channels. Experimental results are compared with the predictions of the modified Lednicky-Lyuboshitz model. The value of R=1.6±0.3 fm is obtained for the root-meansquare spacetime radius of pp emission in 4Hep interactions. The dependence of the correlation function on the total momentum of two emitted protons and on the momentum-transfer direction is investigated. 相似文献
7.
《Nuclear Physics A》1999,650(1):47-61
The halo nuclei 11Be and 11Li have been studied in core-breakup reactions where the halo neutrons are expected to be released without a major distortion due to the reaction. The widths of the halo-neutron momentum distributions have been extracted in coincidence with He fragments, Γ = 32 ± 4 MeV/c, and Li fragments, Γ = 42 ± 4 MeV/c for 11Be and with He fragments, Γ = 42 ± 6 MeV/c for 11Li. The 11Be breakup gives a very low neutron multiplicity of 0.38±0.09 which is a manifestation of the shadowing of the neutron in the core-breakup reaction. This value can be understood from a simple theoretical calculation, which also accounts for the observed transverse momentum widths at small angles. 相似文献
8.
S. B. Dubovichenko 《Physics of Atomic Nuclei》2011,74(3):358-370
Within the potential cluster model where orbital states are classified according to Young diagrams and isospin, astrophysical
S factors are considered for radiative proton capture by 3H and 7Li nuclei at energies of up to 1 and 10 keV, respectively. It is shown that the approach used, which takes into account only
the E1 transition for the p
3H capture process, makes it possible to describe well the most recent experimental data at c.m. energies in the range from
50 keV to 5MeV. In the case of proton capture by 7Li nuclei, an M1 processwas taken into account in addition to the E1 transition, and a general behavior and the magnitude of the experimental S factor could be correctly reproduced owing to this at astrophysical energies, including the region around the resonance at
0.441 MeV (in the laboratory frame). 相似文献
9.
D. A. Artemenkov V. Bradnova G. I. Britvich A. A. Zaitsev P. I. Zarubin I. G. Zarubina V. A. Kalinin R. R. Kattabekov N. K. Kornegrutsa M. Yu. Kostin A. V. Maksimov K. Z. Mamatkulov E. Mitseva A. Neagu V. A. Pikalov M. K. Polkovnikov P. A. Rukoyatkin V. V. Rusakova V. R. Sarkisyan R. Stanoeva E. Firu M. Haiduc S. P. Kharlamov 《Physics of Atomic Nuclei》2017,80(6):1126-1132
The results obtained by estimating the contribution of 8Be and 9B nuclei to the coherent dissociation of 10C, 10B, and 12C relativistic nuclei in nuclear track emulsions (“white” stars) are presented. The selection of white stars accompanied by 9B leads to a distinct peak appearing in the distribution of the excitation energy of 2α2p ensembles and having a maximum at 4.1 ± 0.3 MeV. A 8Be nucleus manifests itself in the coherent-dissociation reaction 10B → 2He + H with a probability of (25 ± 5)%, (14 ± 3)% of it being due to 9B decays. The ratio of the branching fractions of the 9B + n and 9Be + p mirror channels is estimated at 6 ± 1. An analysis of the relativistic dissociation of 12C nuclei in a nuclear track emulsion revealed nine 3α events corresponding to the Hoyle state. 相似文献
10.
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
11.
Yu. B. Gurov E. M. Kalinin V. S. Karpukhin S. V. Lapushkin I. V. Laukhin V. A. Pechkurov V. G. Sandukovsky B. A. Chernyshev T. D. Shchurenkova 《Bulletin of the Russian Academy of Sciences: Physics》2010,74(4):433-436
The results from an experimental search for the production of heavy lithium isotopes 11,12Li in stopped π−-meson absorption reactions on a 14C radioactive target are presented. A pronounced peak is observed in the missing mass spectrum of the 14C(π−, pp)X reaction, which is associated with the formation of a nucleon-unstable 12Li state with the following resonance parameters: E
R
= 4.0 ± 0.2 MeV and Γ = 1.1 ± 0.2 MeV. Resonance parameters of three low-lying 11Li excited states were determined in the 14C(π−, pd)X, reaction. 相似文献
12.
N. Burtebayev S. V. Artemov B. A. Duisebayev Zh. K. Kerimkulov S. B. Kuranov S. B. Sakuta 《Physics of Atomic Nuclei》2010,73(5):746-756
At an energy of 25 MeV and in the angular range 7°−175° in the laboratory frame, angular distributions were measured for elastic
deuteron scattering on 6Li nuclei and for the respective inelastic-scattering processes accompanied by the transitions to the ground state (1+) of
the 6Li nucleus and to its excited state at E
x
= 2.186 MeV (J
π = 3+). The resulting data were analyzed on the basis of the optical model of the nucleus and the coupled-reaction-channel method
with allowance for the mechanism of alpha-particle-cluster exchange. It is shown that only upon including, in the analysis,
channel coupling and the exchange mechanism can the experimental cross sections for elastic and inelastic scattering be reproduced
over the entire range of angles. 相似文献
13.
L. A. Vaishnene V. G. Vovchenko Yu. A. Gavrikov V. I. Murzin V. V. Polyakov M. G. Tverskoi O. Ya. Fedorov Yu. A. Chestnov A. V. Shvedchikov A. I. Shchetkovskii 《Physics of Atomic Nuclei》2011,74(1):115-121
The total cross sections for 197Au and 203Tl fission induced by protons of energy varied from about 200 to 1000 MeV with a step of about 100 MeV are measured. New approximations
to the energy dependences of the cross sections for the proton-induced fission of 197Au, 203Tl, natPb, and 209Bi nuclei are presented and discussed. For all of these nuclei, exponential functions are used as approximations. 相似文献
14.
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
15.
16.
M. G. Gornov M. N. Ber Yu. B. Gurov S. V. Lapushkin P. V. Morokhov V. A. Pechkurov N. O. Poroshin V. G. Sandukovsky M. V. Tel’kushev B. A. Chernyshev 《JETP Letters》2003,77(7):344-348
The formation of the 5H superheavy hydrogen isotope was experimentally sought in the reactions induced by stopped π? mesons absorbed by 9Be nuclei. Peaks in missing-mass spectra were observed in two reaction channels, 9Be(π?, pt)X and 9Be(π?, dd)X, and were attributed to the 5H resonance states. The lowest state has parameters Er=5.5±0.2 MeV and Г=5.4±0.5 MeV [Er is the resonance energy measured from the (triton + two neutrons) threshold]. Therefore, 5H is bound more weakly than 4H. Excited states of 5H were also observed. All three resonance levels (E1r=10.6±0.3 MeV, Г1r=6.8±0.5 MeV; E2r=18.5±0.4 MeV, Г2r=4.8±1.3 MeV; E3r=26.7±0.4 MeV, Г3r=3.6±1.3 MeV) can decay into five free nucleons. 相似文献
17.
Yu. B. Gurov E. M. Kalinin V. S. Karpukhin L. Yu. Korotkova S. V. Lapushkin I. V. Laukhin P. V. Morokhov V. G. Sandukovsky B. A. Chernyshev 《Bulletin of the Russian Academy of Sciences: Physics》2011,75(4):459-462
A search for the 10Li formation was performed in missing mass spectra measured in stopped pion absorption reactions 14C(π
−, pt)X and 14C(π
−, dd)X. Three excited states of 10Li were found. The broad state with a resonance energy of E
R
= 6.13 ± 0.11 MeV has the highest excitation energy in comparison with levels observed earlier. 相似文献
18.
We present deuteron and triton spectra measured at 12 laboratory angles from the reaction of 50 MeV 7Li on 56Fe together with evaporative components as modeled by CASCADE and fitted to the backward angle data. The deuteron and triton “break-up” spectra obtained by subtracting the evaporative components from the measured spectra are also presented. The break-up of the 7Li projectile near the surface occurs with high probability and the major fraction of the break-up cross-section is taken by (7Li,α) transfer process. A crude estimate of the fraction of the total cross-section is found to be of the same order of magnitude as the overall spectroscopic factor determined by the diffraction model. The value of the estimated fraction of total cross section at 50 MeV incident energy is compared to that at 68 MeV incident energy for the same reaction. However, these values of estimated fraction of total cross section are found very much consistent with the measured yields at both incident energies. The importance of the level density parameter in locating the maximum of excitation energy is indicated in the diffraction model. 相似文献
19.
Proton-neutron correlations in 4Hep interactions are studied in an exclusive experiment by using a 2-m bubble chamber exposed to a 5-GeV/c beam of α particles (the kinetic energy of the protons in the nucleus rest frame is T p = 620 MeV). Data on the production of pn pairs in 4π geometry for three channels, where it is possible to reconstruct the neutron momentum unambiguously, are used to determine the pn correlation function in 4Hep interactions. The experimental results are compared with the predictions of a modified Lednicky-Lyuboshitz model. The value obtained for the root-mean-square radius of the pn-emission region is R pn = 2.1 ± 0.3 fm. The dependence of the correlation function on the modulus of the total momentum of the emitted nucleon pair and on the direction of the momentum transfer is studied. An indication that the emission of a pn pair proceeds predominantly through the production of a virtual deuteron is obtained. 相似文献
20.
We calculate the electric dipolarizability of 7Li nucleus within the cluster model and estimate a value of about 0.0188 fm3. We also discuss the possibility of observing this in the scattering of 7Li from a 208Pb target at energies about 30 MeV.
相似文献