An improved method is proposed for the extraction of the symmetry energy coefficient relative to the temperature, asym/T, for the heavy-ion reactions near the Fermi energy region, based on the modified Fisher Model(MF...An improved method is proposed for the extraction of the symmetry energy coefficient relative to the temperature, asym/T, for the heavy-ion reactions near the Fermi energy region, based on the modified Fisher Model(MFM). This method is applied to the primary fragments of the Anti-symmetrized Molecular Dynamics(AMD)simulations for the reactions of40 Ca + 40 Ca at 35 Me V/nucleon. The density and the temperature at the fragment formation stage are extracted using a self-consistent method.展开更多
We present the proton-total reaction cross sectionsσR by comparing the experimental data with the Glauber model calculation using four sets of nucleon-nucleon cross sections used in literature(free nucleon-nucleon cr...We present the proton-total reaction cross sectionsσR by comparing the experimental data with the Glauber model calculation using four sets of nucleon-nucleon cross sections used in literature(free nucleon-nucleon cross sections(NNCS),phenomenological NNCS,Bruckner-type NNCS and Pauli NNCS)and different nuclear densities for symmetric and asymmetric nuclei.For light symmetric target nuclei,the experimentalσR data are well reproduced by the former three NNCS with the ground state density distributions of relativistic mean-field theory.On the other hand,for asymmetry heavier target nuclei,the calculations of theσR data depend significantly on the nuclear density distribution at large radius in the low energy region.The experimentalσR of these nuclei are well reproduced by the empirical 3 pF density distribution and the in-medium NNCS.The neutron surface distributions are also discussed based on the 3 pF nuclear charge distributions.展开更多
The gamma response function is required for energy calibration of EJ301 （5 cm in diameter and 20 cm in height） organic liquid scintillator detector by means of gamma sources. The GEANT4 and FLUKA Monte Carlo simulat...The gamma response function is required for energy calibration of EJ301 （5 cm in diameter and 20 cm in height） organic liquid scintillator detector by means of gamma sources. The GEANT4 and FLUKA Monte Carlo simulation packages were used to simulate the response function of the detector for standard 22Na, 60Co, 137Cs gamma sources. The simulated results showed a good agreement with experimental data by incorporating the energy resolution function to simulation codes. The energy resolution and the position of the maximum Compton electron energy were obtained by comparing measured light output distribution with simulated one. The energy resolution of the detector varied from 21.2% to 12.4% for electrons in the energy region from 0.341 MeV to 1.12 MeV. The accurate position of the maximum Compton electron energy was determined at the position 81% of maximum height of Compton edges distribution. In addition, the relation of the electron energy calibration and the effective neutron detection thresholds were described in detail. The present results indicated that both packages were suited for studying the gamma response function of EJ301 detector.展开更多
基金Supported by the National Natural Science Foundation of China(Nos.11075189 and 11205209)100 Persons Project(Nos.0910020BR0and Y010110BR0)+2 种基金ADS project 302(No.Y103010ADS)of the Chinese Academy of Sciencesthe U.S.Department of Energy(No.DE-FG03-93ER40773)the Robert A.Welch Foundation(No.A0330)
文摘An improved method is proposed for the extraction of the symmetry energy coefficient relative to the temperature, asym/T, for the heavy-ion reactions near the Fermi energy region, based on the modified Fisher Model(MFM). This method is applied to the primary fragments of the Anti-symmetrized Molecular Dynamics(AMD)simulations for the reactions of40 Ca + 40 Ca at 35 Me V/nucleon. The density and the temperature at the fragment formation stage are extracted using a self-consistent method.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11105187 and 11075189, the ＇100 Talents Project＇ of Chinese Academy of Sciences under Grant Nos 0910020BR0 and Y010110BR0, ADS project 302 of Chinese Academy of Sciences under Grant No Y103010ADS, and the Program of the Visiting Professorship of Senior International Scientists of Chinese Academy of Sciences.
基金Supported by the National Natural Science Foundation of China(No 11075189)100 Persons Project(0910020BR0,Y010110BR0)ADS Project(Y103010ADS)of the Chinese Academy of Sciences.
文摘We present the proton-total reaction cross sectionsσR by comparing the experimental data with the Glauber model calculation using four sets of nucleon-nucleon cross sections used in literature(free nucleon-nucleon cross sections(NNCS),phenomenological NNCS,Bruckner-type NNCS and Pauli NNCS)and different nuclear densities for symmetric and asymmetric nuclei.For light symmetric target nuclei,the experimentalσR data are well reproduced by the former three NNCS with the ground state density distributions of relativistic mean-field theory.On the other hand,for asymmetry heavier target nuclei,the calculations of theσR data depend significantly on the nuclear density distribution at large radius in the low energy region.The experimentalσR of these nuclei are well reproduced by the empirical 3 pF density distribution and the in-medium NNCS.The neutron surface distributions are also discussed based on the 3 pF nuclear charge distributions.
文摘研究了对BC501A液体闪烁体对γ射线的光输出响应特性。实验上利用γ放射源(60Co,137Cs)测量了不同光电倍增管高压下,尺寸为Φ5.08 cm×5.08 cm的BC501A液体闪烁体探测器的脉冲幅度谱。利用Geant4软件进行模拟,计算结果与实验数据很好地符合,得到了能量分辨函数及能量刻度曲线。利用Geant4研究了BC501A的脉冲幅度谱的康普顿边缘Ec、康普顿峰Emax及康普顿半高点E1/2与能量分辨率的关系。同时模拟结果显示,随γ射线能量(0.2～3 Me V)的增加,康普顿边缘位置Nc/Nmax从0.8至0.7线性减少。
基金National Natural Science Foundation of China(11075189)Hundred Talent Program of Chinese Academy of Sciences(0910020BR0,Y010110BR0)Strategic Priority Research Program of Chinese Academy of Sciences(XDA03030200)~~
基金Supported by National Natural Science Foundation of China(11075189)100 Persons Project(0910020BR0,Y010110BR0)ADS Project 302(XDA03030200) of the Chinese Academy of Sciences
文摘The gamma response function is required for energy calibration of EJ301 （5 cm in diameter and 20 cm in height） organic liquid scintillator detector by means of gamma sources. The GEANT4 and FLUKA Monte Carlo simulation packages were used to simulate the response function of the detector for standard 22Na, 60Co, 137Cs gamma sources. The simulated results showed a good agreement with experimental data by incorporating the energy resolution function to simulation codes. The energy resolution and the position of the maximum Compton electron energy were obtained by comparing measured light output distribution with simulated one. The energy resolution of the detector varied from 21.2% to 12.4% for electrons in the energy region from 0.341 MeV to 1.12 MeV. The accurate position of the maximum Compton electron energy was determined at the position 81% of maximum height of Compton edges distribution. In addition, the relation of the electron energy calibration and the effective neutron detection thresholds were described in detail. The present results indicated that both packages were suited for studying the gamma response function of EJ301 detector.
