1995 Vol. 19, No. 3

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First Study of EC/β+ Decay Schemes for Neutron-Deficient Isotopes 153Er and 157Yb
Xu Shuwei, Xie Yuanxiang, Pan Qiangyan, Zhang Juping, Zhang Xueqian, Wang Yihao, Ge Yuanxiu, Yin Xijin, Wang Chunfang, Zhang Tianmei, Liu Zhong, Guo Bing, Luo Yixiao, Xing Zheng, Chen Xingqu
1995, 19(3): 193-202.
153Er and 157Yb were produced via xu fusion-evaporation reaction by irradiation of 142Nd and 147Sm with 16O, respectively. A He-jet recoil tape transport system, X-γ and γ-γ coincidence measurements were employed to separate and identify the reaction products and to study the EC/β+ decay of 153Er and 157Yb. The EC/β+ decay schemes of 153Er and 157Yb have been proposed for the first time, from which a new three qussi-particle state and two new single proton states have been assigned to 153Ho, and a new isomer and a new rotational band have been assigned to 157Tm. According to systematic behaviour of the low-laying energy levels for odd holmium and odd thulium isotopes with N=82-102, it can be seen that the change from spherical to deformed shapes of nuclear ground states in the two isotope chains appears between N=86 and 88.
First Observation of β-delayed Proton Decay of the Proton Drip Line Nuclide 19Na
Xu Xiaoji, Ma Ruichang, Huang Wenxue, Hu Zhiqiang, Guo Junsheng, Guo Yingxiang, Xu Lianlian, Liu Hongye, Luo Yixiao, Wang Shuhong, Kong Dengming, Qiao Jimin
1995, 19(3): 203-208.
19Na, a nuclide on proton drip line, was studied by 20Ne(p,2n) 19Na reaction.Experiment was performed on the proton linear accelerator at institute of High Energy Physics, The Chinese Academy of Sciences. The new decay mode of β-delayed proton decay was observed for the first time. The half-life of 19Na was determined to be 47±20ms and its proton energy was measured to be 1.10±0.08MeV which is corresponding to super-allowed beta transition of 19Na to excited state of 7.62MeV,the isospin analog state with T=3/2 in 19Ne, and subsquent proton emission to the ground state of 18F.
Monte Carlo study for strategies of Tau mass measurement
Li Jin, Li Yushan, Qi Nading, Xue Shengtian, Wang Ping, Hu Tao, Ma Donghong, Zhang Jiawen, Zhu Qiming, Jiang Chunhua, Jiang Zhijing
1995, 19(3): 209-216.
Before the τ mass experiment, several measuremental strategies were studied in detail by Monte Carlo simulations. After they were widely compared, the likelihood method was suggested to determine the energy points and the possible measuremental accuracy has been given. The effects of many factors to the measurement were simulated, such as the event selection efficiency, energy spread etc, and necessary requirements were proposed to the experiment.
Azimuthal Correlation in Nuclear Multifragmentation at Intermediate-Energy
Liu Fuhu
1995, 19(3): 217-222.
Under the assumption that the fragments present isotropic emitting in the rest frame of the source, we have considered the electromagnetic interactions among fragments and investigated the azimuthal correlation between the fragments in intermediate-energy nuclear multifragmentation. The calculated results are in agreement with the experimental data in the energy range from 500 to 980A MeV.
Measurement of Angular Distribution and Cross Section For 58Ni(n,α) 55Fe Reaction at 5.1 MeV
Tang Guoyou, Bai Xinhua, Shi Zhaomin, Chen Jinxiang
1995, 19(3): 223-228.
The measurement of 58Ni(n,α) 55Fe angular distribution using a gridded-ionization chamber at incident energy 5.1MeV was. carried out. Using fission chamber of 238U to determine neutron fluency, 47.4±5.0 mb of cross section was obtained for 58Ni (n,α) 55Fe. Comparison between experiment and theoretical calculation supports that angular distribution of 58Ni(n, α) 55Fe at neutron energy of 5.1MeV can be described by the model of compound nucleus.
q-deformed Quantum Affine Algebra in Zn Lattice Model
Shi Kangjie, Yang Wenli, Hou Boyu, Fan Heng
1995, 19(3): 229-240.
The Zn-Baxter model in the principal regime is studied, and it is verified that two different Boltzmann weights are conjugate to each other. Using the two different startriangular relations and antisymmetric fusion, a realization of q-deformed quantum affine algebra is obtained.
Casimir Effect at Finite Temperature
Zheng Taiyu
1995, 19(3): 241-244.
The contribution of the free electromagnetic field and internal fermion oneloop to Casimir force between two parallel conducting plates at finite temperature are calculated by using the Feynman path integral method.
Further Study on SU(2)×SU(2) Lattice Chiral Model
Huang Liangxin, Li Hong, Chen Tianlun
1995, 19(3): 245-250.
With the Variational-Cumulant Expansion method, the free energy of SU(2)×SU(2) lattice chiral model is calculated to the 5th order correction. The variational parameter is determined by main variational method and accumulation point method, respectively. It is showed that more correspondent internal energy curves and specific heat curves with the MC results can be obtained by the latter one.
Eigenstates of the Second Power of the Annihilation Operator of Two-Parameter Deformed Harmonic Oscillator
Zhou Huanqiang, He Jingsong, Zhang Xinming
1995, 19(3): 251-257.
The eigenstates of the second power of the annihilation operator of the twoparameter deformed harmonic oscillator are constructed, and their completeness is demonstrated in terms of the qs-integration.
Study of SU(2)q,s Coherent State by Using (q,s) Deformed Harmonic Oscillators of SU(2)q,s Quantum Algebra
Yu Zhaoxian, Liu Yehou, Li Qinglin, Liang Bifang
1995, 19(3): 258-263.
The SU(2)q,s coherent state different from Perelomov coherent state is constructed by using the (q,s) deformed harmonic oscillators of the SU(2)q,s quantum algebra. It is shown that the basis function of the SU(2)q,s quantum algebra is orthogonal. The completeness and normalization property of the SU(2)q,s coherent state is studied. It is pointed out that the coherent property of the SU(2)q,s coherent state is affected by q,s parameters, and this is more general than the case of the single parameter SU(2)q coherent state.
Description of p-40Ca Scattering at 800 MeV Using the α-Particle Model
Ruan Wenying, Xie Wenfang
1995, 19(3): 264-269.
In this paper the Glauber theory is used to calculate the differential cross section, analysing power and spin rotation parameter of p-40Ca scattering at 800MeV on the basis of the α-particle model. Reasonably good agreement the experimental data is obtained with. The effect of the p-α phase is also analysed.
Constrained Correlation Dynamics of SU(N) Gauge Theories in Canonical form (Ⅰ) Equations of Motion for Correlation Green's Functions
Wang Shunjin, Guo Hua
1995, 19(3): 270-277.
With the aid of generating-functional technique and in the frame-work of correlation dynamics, we have established the constrained correlation dynamics of SU (N) gauge theories in the temporal gauge and canonical quantization form, and obtained a closed set of equations of motion for correlation Green's functions.
Thomas-Fermi Statistical Model Theory for the Surface Energy of Hot Nuclei
Luo Shuanqun, Wang Zhengxing
1995, 19(3): 278-283.
The surface energy coefficient of nuclear matter σ(T,δ) as a function of temperature T and nuclear asymmetry δ is calculated for the semi-infinite model of nuclear matter, using the temperature-dependent Thomas-Fermi statistical model theory with the Seyler-Blanchard momentum-dependent nonlocal interaction. It was found that the surface energy coefficient can be written approximately as σ(T,δ)=σ0(T)[1+K(T)δ2], where the σ0(T) and K(T) can be fitted as quadratic functions of the temperature T.
Small Angle Scattering Station of BEPC Synchrotron Radiation Laboratory
Dong Baozhong, Sheng Wenjun, Li Guangcheng, Zhang Zhijie
1995, 19(3): 284-288.
The small angle x-ray scattering (SAXS) station is located at 34m from the source in the downstream of the x-ray diffraction station. The station is equipped with a SAXS camera, a detector, an alignment carriage and on-line data acquisition and control system. The SAXS camera consists of a slit-system with position precision 1μm, a remotely controlled sample holder with vertical and horizontal translations at the plane normal to photon beam and a vacuum pipe with 0.13Pa. The research for this station is directed on the static and dynamic structure, phase composition and phase transmission in various fields such as molecular biology, materialscience, polymer chemistry and metallurgy.