1993 Vol. 17, No. S1

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Projectile Fragmentation Reactions Induced by 46.7 MeV/u 12C
Liu Guanhua, Zhan Weniong, Zhu Yongtai, Guo Zhongyan, Hu Xiaoqing, Xi Hongfei, Zhou Jianqun, Yin Shuzhi, Fen Enpu, Zhao Youxiong, Wei Zhiyong, Fan Enjie
1993, 17(S1): 1-8.
The projectile-like fragments (PLF) emitted at forward angles in 46.7 MeV/u 12C induced reactions on different target nuclei have been measured. It was found the most probable energies of PLF products can be interpreted in the framework of an Abrasion model. The longitudinal momentum distribution widths fulfill the Goldhaber formula, and the reduced longitudinal momentum distribution width, extracted from the experiment σ0 is 80±10 MeV/c, which is close to the value obtained in relativistic energy region. After averaging over many fragments, the σ0 is nearly the same for different systems studied.
Fluorescence Properties of Ce3+-Doped BaF2
Xu Zizong, Gong Zhufang, Chang Jin, Shi Chaoshu, Shen Dingzhong, Yuan Xianglong, Yin Zhiwen
1993, 17(S1): 9-16.
The spectra and the decay times of a series of Ce3+-doped BaF2 crystals have been measured. The results demonstrate that a BaF2 with a proper amount of Ce3+ doped have outstanding advantages:the emission spectra shift from LTV band towards blue band, a near blue fluorescence with quite fast decay time (80 ns) replaces the slow component (~600 ns) and very fast one (~0.8 ns) of undoped BaF2. The intensity of the new component is comparable with the sum of the odd ones.
Light Charged Particle Measurement of 46.7 MeV/u 12C + 58Ni Reactions
Xi Hongfei, Zhan Wenlong, Zhu Yongtai, Guo Zhongyan, Hu Xiaoqing, Liu Guanhua, Zhou Jianqun, Yin Shuzhi, Zhao Youxiong, Wei Zhiyong, Fan Enjie
1993, 17(S1): 17-24.
The experiment results from the light particle correlation measurement obtained in 12C(46.7 MeV/u) + 58Ni reaction by using a 9-element CsI(Tl) hodoscope are reported. The definition of the correlation function and its extraction method from the experimental data are discussed in detail. In this paper, the decay of the unstable particles is studied. The correlation functions of various particle combination on 58Ni target are given.
Precise Measurement of Gamma Ray Energies with HPGe Spectrometer by Slithering Comparison Method
Zhang Tianbao, Wang Shuying, Wang Haidong, Shen Zhiqi, Meng Bonian
1993, 17(S1): 25-31.
The energies of γ-rays from some nuclides around 500 keV have been measured by a slithering comparison with the precisely known γ-energies of 192Ir. The energies determined by this method are:477603.18±0.44 eV for 7Be, 511852.70±0.58 eV for 106Ru, 514004.87±0.52 eV for 85Sr, 520399.01±0.63 eV for 83Rb, 529594.48±0.69 eV for 83Rb and 552551.14±0.68 eV for 83Rb. Recalculate the result of a previous experiment by using the new energy measurement, the value of electron mass is obtained as 510998.6±1.1 eV which is in good agreement with the recently adjusted value of electron mass.
Research for Crystallization of Metallic Glass Pd79.5Ni4Si16.5
Han Rongdian, Weng Huimin, Zhou Xianyi, Xu Jihua, Zhu Jingsheng, Li Xiaoguang, Sha Jian, Wang Jingcheng
1993, 17(S1): 33-37.
The monoenergetic slow positron beam was first used to study the crystallization process of metallic glasses. The measurement of Doppler broadening spectra as a function of positron beam energy was performed on the samples of the metallic glass Pd79.5Ni4Si16.5 with various states (i.e., the as-quenched state, structural relaxation states and crystalline states). It is shown that there are a great number of the vacancy-type defects in the as-quenched state sample. Its crystallization process starts at the sample surfaces. The present research indicates that the slow positron annihilation spectroscopy (SPAS) is one of most effective methods for studying the crystallization process of metallic glasses.
Transport of Charged Particle Beams in Nonlinear Periodic Fields
Yu Qingchang
1993, 17(S1): 39-43.
In this paper, the transport of charged particle beams in nonlinear periodic fields is studied. By means of mapping technique the emittance plots of beams matched to the nonlinear periodic fields can be obtained. The variance of emittance plots and the beam envelopes are periodic, and their periods are equal to the period of the field.
Variational Study of 3-Dimensional SU(2) Lattice Gauge Theory with Independent Plaquette Trial Action
Liu Jinming, Gong Di
1993, 17(S1): 45-52.
The phase structure of 3-dimensional SU/(2) lattice gauge theory is studied by using variational method with an independent plaquette trial action. The mean-plaquette internal energy Ep~β curve is smooth, which shows only one confining phase, and is better than that given by independent link trial action.
Average Yields of Long-Lived Charged Particles in High Energy e+e- Anmiiilation
Chen Esheng
1993, 17(S1): 53-63.
Based on the quark production rule and quark combination rule, the average yields of long-lived charged particles and average charged multiplicities in high energy e+e- annihilation have been studied. The calculated yields of hadrons, average charged multiplicities and their energy dependences are all consistent with the available data.
Bosonic Superconformal Toda Theory and Dressing Symmetry
Zhao Liu, Yang Wenli
1993, 17(S1): 65-72.
The dressing transformations of the basic fields and the classical chiral operators in the bosonic superconformal Toda theory are analyzed, starting from the r-matrix formulation of this model. After quantization, we obtain the corresponding quantum dressing group.
Competition Between Fragmentation and Transfer in 46.7 MeV/u 12C Induced Reactions
Liu Guanhua, Zhan Wenlong, Zhu Yongtai, Guo Zhongyan, Hu Xiaoqing, Xi Hongfei, Zhou Jianqun, Yin Shuzhi, Feng Enpu, Zhao Youxiong, Wei Zhiyong, Fan Enjie
1993, 17(S1): 73-80.
The coexistence and competition between fragmentation and transfer in the 46.7 MeV/u 12C induced reactions have been discussed. The reduced longitudinal momentum distribution width for the transfer reaction, extracted from our experiment, is 44±10 MeV/c, which is smaller than that for the fragmentation (80±10 MeV/c). The probabilities for both the projectile fragmentation and the transfer processes are observed to be dependent on the structure of the transferred cluster.
Analysis of Relativistic Optical Potential for Medium-Energy Protons
Feng Dachun, Liu Wenqin, Ma Zhongyu
1993, 17(S1): 81-88.
The influence of the parameters of the relativistic optical potential on the nucleon scattering properties, such as cross sections, angular distributions and spin observables etc., is studied based on a set of global Dirac phenomenological optical potential. It is shown that, in contrast with the case at low energies, the total scattering cross sections vary slowly with the energy and depend weakly on the potentials at Ep <300 MeV. The differential cross sections and spin observables depend not only on the volume integrals of the optical potentials, but also on their strengths and shapes. The applicability of the relativistic microscopic optical potential based on the Walecka model in the medium energy region is also discussed in this paper.
Influence of Finite Collision Time on Energy Density in Relativistic Heavy Ion Collisions
Soren P. Sorensen, Zhao Weiqin
1993, 17(S1): 89-93.
The space-time development of the energy density reached in relativistic heavy ion collisions is analyzed based on the Monte Carlo code ODEN. The results show that the actually reached energy density is considerably lower than Bjorken's estimation due to the finite collision time.