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
At 45 MeV/u an experiment on fragmentation of projectile(<sup>20</sup>Ne)on <sup>165</sup>Ho was performed.An average reduced width σ<sub>0</sub> of 84.3±6.6 MeV/c was obtaine...At 45 MeV/u an experiment on fragmentation of projectile(<sup>20</sup>Ne)on <sup>165</sup>Ho was performed.An average reduced width σ<sub>0</sub> of 84.3±6.6 MeV/c was obtained by separating the break=up of all com-plex fragments of <sup>20</sup>Ne from the evaporation part of compound nucleus in momentum spectra.展开更多
The collective flow for <sup>64</sup>Zn+<sup>27</sup>Al system is measured at intermediate energyby using a 4π multidetector array in conjunction with an array of Si telescopes.Theevents have ...The collective flow for <sup>64</sup>Zn+<sup>27</sup>Al system is measured at intermediate energyby using a 4π multidetector array in conjunction with an array of Si telescopes.Theevents have been sorted versus the impact parameter by means of global variables.Three methods of reaction plane determination are compared:sphericity tensor method,transverse momentum analysis,and azimuthal correlation method.For this system,thetransverse momentum analysis method is the best one.展开更多
In this article,we investigate the dependence of nuclear temperature on emitting source neutron-proton(N/Z)asymmetry with light charged particles(LCPs)and intermediate mass fragments(IMFs)generated from intermediate-v...In this article,we investigate the dependence of nuclear temperature on emitting source neutron-proton(N/Z)asymmetry with light charged particles(LCPs)and intermediate mass fragments(IMFs)generated from intermediate-velocity sources in thirteen reaction systems with different N/Z asymmetries,^(64)Zn on^(112)Sn,and^(70)Zn,^(64)Ni on^(112,124)Sn,^(58,64)Ni,^(197)Au,and^(232)Th at 40 MeV/nucleon.The apparent temperature values of LCPs and IMFs from different systems are deduced from the measured yields using two helium-related and eight carbon-related double isotope ratio thermometers,respectively.Then,the sequential decay effect on the experimental apparent temperature deduction with the double isotope ratio thermometers is quantitatively corrected explicitly with the aid of the quantum statistical model.The present treatment is an improvement compared to our previous studies in which an indirect method was adopted to qualitatively consider the sequential decay effect.A negligible N/Z asymmetry dependence of the real temperature after the correction is quantitatively addressed in heavy-ion reactions at the present intermediate energy,where a change of o.1 units in source N/Z asymmetry corresponds to an absolute change in temperature of an order of 0.03 to 0.29 MeV on average for LCPs and IMFs.This conclusion is in close agreement with that inferred qualitatively via the indirect method in our previous studies.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
An attempt is made to study the symmetry energy at the time of primary fragment formation from the experimentally observed cold fragments for a neutron-rich system of ^64Ni ＋ ^9Be at 140 MeV/nucleon,utilizing the rec...An attempt is made to study the symmetry energy at the time of primary fragment formation from the experimentally observed cold fragments for a neutron-rich system of ^64Ni ＋ ^9Be at 140 MeV/nucleon,utilizing the recent finding that the excitation energy becomes lower for more neutron-rich isotopes with a given Z value.The extracted α（sym）/T values from the cold fragments,based on the Modified Fisher Model（MFM）,are compared to those from the primary fragments of the antisymmetrized molecular dynamics（AMD） simulation and become consistent with the simulation when the I = N —Z value becomes larger,indicating that the excitation energy of these neutron-rich isotopes is indeed lower.展开更多
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.
基金①The project supported by the U.S.Department of Energy.the Robert A.Welch Foundation theNational Natural Science Foundation of China
文摘At 45 MeV/u an experiment on fragmentation of projectile(<sup>20</sup>Ne)on <sup>165</sup>Ho was performed.An average reduced width σ<sub>0</sub> of 84.3±6.6 MeV/c was obtained by separating the break=up of all com-plex fragments of <sup>20</sup>Ne from the evaporation part of compound nucleus in momentum spectra.
文摘The collective flow for <sup>64</sup>Zn+<sup>27</sup>Al system is measured at intermediate energyby using a 4π multidetector array in conjunction with an array of Si telescopes.Theevents have been sorted versus the impact parameter by means of global variables.Three methods of reaction plane determination are compared:sphericity tensor method,transverse momentum analysis,and azimuthal correlation method.For this system,thetransverse momentum analysis method is the best one.
基金Supported by the National Natural Science Foundation of China(12275186,11705242,12175156,11805138,11905120)the Fundamental Research Funds For the Central Universities in China(YJ201954,YJ201820)。
文摘In this article,we investigate the dependence of nuclear temperature on emitting source neutron-proton(N/Z)asymmetry with light charged particles(LCPs)and intermediate mass fragments(IMFs)generated from intermediate-velocity sources in thirteen reaction systems with different N/Z asymmetries,^(64)Zn on^(112)Sn,and^(70)Zn,^(64)Ni on^(112,124)Sn,^(58,64)Ni,^(197)Au,and^(232)Th at 40 MeV/nucleon.The apparent temperature values of LCPs and IMFs from different systems are deduced from the measured yields using two helium-related and eight carbon-related double isotope ratio thermometers,respectively.Then,the sequential decay effect on the experimental apparent temperature deduction with the double isotope ratio thermometers is quantitatively corrected explicitly with the aid of the quantum statistical model.The present treatment is an improvement compared to our previous studies in which an indirect method was adopted to qualitatively consider the sequential decay effect.A negligible N/Z asymmetry dependence of the real temperature after the correction is quantitatively addressed in heavy-ion reactions at the present intermediate energy,where a change of o.1 units in source N/Z asymmetry corresponds to an absolute change in temperature of an order of 0.03 to 0.29 MeV on average for LCPs and IMFs.This conclusion is in close agreement with that inferred qualitatively via the indirect method in our previous studies.
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.
基金Supported by National Natural Science Foundation of China(U1432247,11605097)National Basic Research Program of China(973Program,2014CB845405)Doctoral Scientific Research Foundation of Inner Mongolia University for the Nationalities(BS365)
文摘An attempt is made to study the symmetry energy at the time of primary fragment formation from the experimentally observed cold fragments for a neutron-rich system of ^64Ni ＋ ^9Be at 140 MeV/nucleon,utilizing the recent finding that the excitation energy becomes lower for more neutron-rich isotopes with a given Z value.The extracted α（sym）/T values from the cold fragments,based on the Modified Fisher Model（MFM）,are compared to those from the primary fragments of the antisymmetrized molecular dynamics（AMD） simulation and become consistent with the simulation when the I = N —Z value becomes larger,indicating that the excitation energy of these neutron-rich isotopes is indeed lower.
