The primary fragments in ^(40)Ca +^(40)Ca reactions at 35,50,80,100,140,and 300 MeV/u were simulated using the antisymmetrized molecular dynamics model,in the phase space at t=300 fm/c with a coalescence radius R_c=5 ...The primary fragments in ^(40)Ca +^(40)Ca reactions at 35,50,80,100,140,and 300 MeV/u were simulated using the antisymmetrized molecular dynamics model,in the phase space at t=300 fm/c with a coalescence radius R_c=5 fm.The standard Gogny interactions g0,g0 as,and gOass were adopted in simulating the collisions at an impact parameter of b=0 fm.It was found,using an isobaric yield ratio method,that temperature of the primary fragment depends on the incident energy and hardness of the interaction potential.The temperature obtained in this work agrees with the results by the self-consistent fitting method.展开更多
An improved thermometer(TIB) is proposed for intermediate-mass fragments via the difference between isobaric yield ratios.The residual free energy of three isobars is replaced by that of the binding energy.The measure...An improved thermometer(TIB) is proposed for intermediate-mass fragments via the difference between isobaric yield ratios.The residual free energy of three isobars is replaced by that of the binding energy.The measured fragments in the 140 A MeV ^(40,48) Ca +9Be(181Ta) and^(58,64) Ni +~9Be(^(181)Ta) reactions are analyzed to obtain T_(IB) ranging from 0.6 to 3.5 Me V.TIBis suggested to be a direct determination of temperature avoiding the fitting procedure.展开更多
The mass dependence of critical parameters for the liquid-gas phase transition and multiplicity of intermediate mass fragment in the heavy ion reaction is qualitatively explored under the framework of lattice gas mode...The mass dependence of critical parameters for the liquid-gas phase transition and multiplicity of intermediate mass fragment in the heavy ion reaction is qualitatively explored under the framework of lattice gas model.Some results are compared with experimental data.展开更多
Exclusive intermediate mass fragments（IMFs）are measured at forward angles forthe <sup>40</sup>Ar+<sup>nal</sup>Ag reaction at 30 MeV/u.The impact parameter is determined using the totaltransv...Exclusive intermediate mass fragments（IMFs）are measured at forward angles forthe <sup>40</sup>Ar+<sup>nal</sup>Ag reaction at 30 MeV/u.The impact parameter is determined using the totaltransverse momentum method and linear momentum transfer method.IMFs emitted at forwardangles mainly come from projectile fragmentation in peripheral collisions,while IMFs in centralcollision mainly come from decay of hot target-like sources.IMFs from both projectile-like andtarget-like sources are observed in mid-central collision.In addition,the third component,non-equilibrium mid-rapidity components are observed in central,mid-central and peripheralcollisions.展开更多
Inclusive Intermediate-Mass Fragments（IMFs）are measured at seven angles for the<sup>40</sup>Ar+Ag reaction at 25 MeV/u.The energy spectra of IMF from Li to F are obtained.A thermal mod-el with the same p...Inclusive Intermediate-Mass Fragments（IMFs）are measured at seven angles for the<sup>40</sup>Ar+Ag reaction at 25 MeV/u.The energy spectra of IMF from Li to F are obtained.A thermal mod-el with the same parameters well fits the energy spectra of all IMFs at backward angles.These IMFs areevaporated from hot nuclei formed in an incomplete fusion process.The angular distribution and Z distri-bution are calculated with the statistical code GEMINI.展开更多
The fragment angular distributions for the 600 MeV <sup>40</sup>Ar+<sup>197</sup>Au reaction aremeasured using off line γ-ray spectroscopy technique.The features of the fragment an-gular distr...The fragment angular distributions for the 600 MeV <sup>40</sup>Ar+<sup>197</sup>Au reaction aremeasured using off line γ-ray spectroscopy technique.The features of the fragment an-gular distributions and the reaction mechanisms for the produced fragments are dis-cussed.展开更多
A scaling phenomenon has been found for the cross section of a fragment, which is defined as a "square" cross section(SCS).This phenomenon can unify the cross sections of fragments in projectile fragmentatio...A scaling phenomenon has been found for the cross section of a fragment, which is defined as a "square" cross section(SCS).This phenomenon can unify the cross sections of fragments in projectile fragmentation(PF) reactions. An empirical formula is proposed to calculate SCSfor a fragment with parameters determined by an extensive investigation of measured reactions ranging from Fermi energies to relativistic energies. The scaling phenomenon of SCShas been verified using different techniques,showing that the scaling of SCSgenerally exists in PF reactions. The concept of SCS, which can be assumed as a standard value for a fragment, is shown to accurately predict the cross sections of isotopes in PF reactions with incident energies ranging from tens of A MeV to approximately 1000 A MeV.展开更多
基金supported by the Program for Science and Technology Innovation Talents in Universities of Henan Province(13HASTIT046)Henan Normal University for the Excellent Youth(154100510007)the support from the Creative Experimental Project of National Undergraduate Students(CEPNU201510476017)
文摘The primary fragments in ^(40)Ca +^(40)Ca reactions at 35,50,80,100,140,and 300 MeV/u were simulated using the antisymmetrized molecular dynamics model,in the phase space at t=300 fm/c with a coalescence radius R_c=5 fm.The standard Gogny interactions g0,g0 as,and gOass were adopted in simulating the collisions at an impact parameter of b=0 fm.It was found,using an isobaric yield ratio method,that temperature of the primary fragment depends on the incident energy and hardness of the interaction potential.The temperature obtained in this work agrees with the results by the self-consistent fitting method.
文摘An improved thermometer(TIB) is proposed for intermediate-mass fragments via the difference between isobaric yield ratios.The residual free energy of three isobars is replaced by that of the binding energy.The measured fragments in the 140 A MeV ^(40,48) Ca +9Be(181Ta) and^(58,64) Ni +~9Be(^(181)Ta) reactions are analyzed to obtain T_(IB) ranging from 0.6 to 3.5 Me V.TIBis suggested to be a direct determination of temperature avoiding the fitting procedure.
基金Supported by the National Natural Science Foundation for Distinguished Young Scholar under Grant No.19725521 National Natural Science Foundation under Grant No.19705021Science and Technology Development Foundation of shanghai under Grant No.97QA
文摘The mass dependence of critical parameters for the liquid-gas phase transition and multiplicity of intermediate mass fragment in the heavy ion reaction is qualitatively explored under the framework of lattice gas model.Some results are compared with experimental data.
基金The Project supported by National Natural Science Foundation of China
文摘Exclusive intermediate mass fragments（IMFs）are measured at forward angles forthe <sup>40</sup>Ar+<sup>nal</sup>Ag reaction at 30 MeV/u.The impact parameter is determined using the totaltransverse momentum method and linear momentum transfer method.IMFs emitted at forwardangles mainly come from projectile fragmentation in peripheral collisions,while IMFs in centralcollision mainly come from decay of hot target-like sources.IMFs from both projectile-like andtarget-like sources are observed in mid-central collision.In addition,the third component,non-equilibrium mid-rapidity components are observed in central,mid-central and peripheralcollisions.
基金①The project supported by the National Natural Science Foundation of China
文摘Inclusive Intermediate-Mass Fragments（IMFs）are measured at seven angles for the<sup>40</sup>Ar+Ag reaction at 25 MeV/u.The energy spectra of IMF from Li to F are obtained.A thermal mod-el with the same parameters well fits the energy spectra of all IMFs at backward angles.These IMFs areevaporated from hot nuclei formed in an incomplete fusion process.The angular distribution and Z distri-bution are calculated with the statistical code GEMINI.
基金The project supported by the National Natural Science Foundation of China
文摘The fragment angular distributions for the 600 MeV <sup>40</sup>Ar+<sup>197</sup>Au reaction aremeasured using off line γ-ray spectroscopy technique.The features of the fragment an-gular distributions and the reaction mechanisms for the produced fragments are dis-cussed.
基金supported by the National Natural Science Foundation of China(Grant No.U1732135)the Natural and Science Foundation in Henan Province(Grant No.162300410179)
文摘A scaling phenomenon has been found for the cross section of a fragment, which is defined as a "square" cross section(SCS).This phenomenon can unify the cross sections of fragments in projectile fragmentation(PF) reactions. An empirical formula is proposed to calculate SCSfor a fragment with parameters determined by an extensive investigation of measured reactions ranging from Fermi energies to relativistic energies. The scaling phenomenon of SCShas been verified using different techniques,showing that the scaling of SCSgenerally exists in PF reactions. The concept of SCS, which can be assumed as a standard value for a fragment, is shown to accurately predict the cross sections of isotopes in PF reactions with incident energies ranging from tens of A MeV to approximately 1000 A MeV.
