The most neutron-deficient isotopes215,216 U were produced in the complete-fusion reaction ^(180)W(^(40)Ar, 4-5n)^(215,216) U. Evaporation residues recoiled from the target were separated in-flight from the primary beam by the gas-filled recoil separator SHANS and subsequently identified on the basis of correlated α-decay chains. Two α-decaying states were identified in ^(216)U, one for the ground state and the other for the isomeric state with 8+(πh_(9/2)πf_(7/2)) configuration. The α-decay properties for ^(215,216)U and the systematics of 8+isomeric state in N = 124, 126 isotones were investigated.
We investigate low-lying bound states of the neutron-rich nucleus ^15B by assuming it is a three-body system made of an inert core 13 B and two valence neutrons. The three-body wave functions are obtained using the Faddeev formalism. Special attention is paid to the excited state at 3.48（6） MeV observed in the 13 C（14 C,12 N）15 B reaction, whose properties are less clear theoretically. In our three-body model, besides the ground state 3/21, a second 3/22^-state is discovered at around 3.61 MeV, which might be identified with the excited state observed at3.48（6） MeV. We study this 3/22^-state in detail. It turns out to be a two-neutron halo state with a large matter radius rm≈4.770 fm. ＆nbsp
Continuum Discretized Coupled-Channel（CDCC） model calculations of total, complete and incomplete fusion cross sections for reactions of the weakly bound 6Li with 144,154Sm targets at energies around the Coulomb barrier are presented. In the cluster structure frame of 6Li→α＋d, short-range absorption potentials are considered for the interactions between the ground state of the projectile 6Li and α-d fragments with the target. In order to separately calculate complete and incomplete fusion and to reduce double-counting, the corresponding absorption potentials are chosen to be of different range. Couplings to low-lying excited states 2＋, 3-of 144Sm and 2＋, 4＋ of 154Sm are included. So, the effect on total fusion from the excited states of the target is investigated. Similarly, the effect on fusion due to couplings to resonance breakup states of 6Li, namely, l = 2,Jπ= 3＋, 2＋, 1＋ is also calculated.The latter effect is determined by using two approaches,（a） by considering only resonance state couplings and（b）by omitting these states from the full discretized energy space. Among other things, it is found that both resonance and non-resonance continuum breakup couplings produce fusion suppression at all the energies considered.
Nuclear double β^--decays with two neutrinos were observed for many years and a systematic law describing the relation between their half-lives and decay energies was also proposed recently [Phys Rev C, 2014, 89： 064603]. However, double β^＋ -decay （β^＋β^＋） with emission of both two positrons and two neutrinos has not been observed up to date. In this article, we pcrform a systematic analysis on the candidates of double β^＋-decay, based on the 2012 nuclear mass table. Eight nuclei are found to be the good candidates for double β^＋-decay and their half-lives are predicted according to the generalization of the systematic law to double β^＋-decay. As far as we know, there is no theoretical result on double β^＋-decay of nucleus ^154Dy and our result is the first prediction on this nucleus. This is also the first complete research on eight double β^＋-decay candidates based on the available data of nuclear masses. It is expected that the calculated half-lives of double β^＋-decay in this article will be useful for future experimental search of double β^＋-decay.
A theoretical evaluation of the collective excitation spectra of nucleus at large deformations is possible within the framework of the dinuclear system(DNS) model, which treats the wave function of the fissioning nucleus as a superposition of a mononucleus configuration and two-cluster configurations in a dynamical way, permitting exchange of nucleons between clusters. In this work the method of calculation of the potential energy and the collective spectrum of fissioning nucleus at scission point is presented. Combining the DNS model calculations and the statistical model of fission we calculate the angular distribution of fission fragments for the neutron–induced fission of239 Pu.
In this paper,a general method of data transmission system design on PXI platform is proposed.It can be used in readout system design for physical experiments.It aims at providing reusable and general interfaces for customized design of PXI while maintaining the transmission performance.It has three main features:(1)universal logic hardware interface,(2)ethernet based socket software interface,and(3)specific and simple data transmission protocol.Data transmission on PXI bus can be realized with the said two universal interfaces coordinated by this specific protocol.Test shows that this method is feasible and stable.This method can be easily reused in readout system designs for different experiments.
Nuclear double β--decay with two neutrinos is an important decay mode for some unstable nuclei. Based on the available experimental data of nuclear double β--decay, we propose that there is a law between the logarithm of double β--decay half-lives and the reciprocal of the decay energy. The physics behind the law is discussed and it is found that this is associated with the universal properties of the weak interaction. This doubleβ--decay law is similar to the famous Geiger-Nuttall law of α-decay. The law is applied to predictions of the nuclear double β--decay half-lives for six even-even nuclei from Z = 84 to Z = 98 and we found that232 Th is very interesting for future experiments. The branching ratios between double β--decay and α-decay are also estimated for the six even-even nuclei and this is useful for future experimental search of new emitters of doubleβ--decay.
The relativistic mean field（RMF） FSUGold model extended to include hyperons is employed to study the properties of neutron stars with strong magnetic fields.The chaotic magnetic field approximation is utilized.The effect of anomalous magnetic moments（AMMs） is also investigated.It is shown that the equation of state（EOS）of neutron star matter is stiffened by the presence of the magnetic field,which increases the maximum mass of a neutron star by around 6%.The AMMs only have a small influence on the EOS of neutron star matter,and increase the maximum mass of a neutron star by 0.02M（sun）.Neutral particles are spin polarized due to the presence of the AMMs.
Recently,we analyze the α-decay data of even-Z nuclei and propose the new Geiger-Nuttall law where the effects of the quantum numbers of α-core relative motion are naturally embedded in the law [Physical Review C 85,044608(2012)].In this paper,we firstly test whether the new law without any change of parameters can be applied to the α-decays of odd-Z nuclei which are more complicated than those of even-even nuclei.Then the nuclear shell effect around N=126 is analyzed for very proton-rich nuclei with Z=85-92 based on the data of α-decay energies and half-lives.A long-lived island beyond the stable line is proposed where the half-lives of nuclei on this island are abnormally long.The mechanism of the appearance of the island and its significance to other mass ranges are discussed.
