Hot nuclei with differentN/Z ratio were produced by using^(40)Ar beam on^(112)Sn and^(124)Sn target,respectively.The energy spectra and the emission probabilities of hydrogen isotopes are analyzed in the 30 MeV/u^940)...Hot nuclei with differentN/Z ratio were produced by using^(40)Ar beam on^(112)Sn and^(124)Sn target,respectively.The energy spectra and the emission probabilities of hydrogen isotopes are analyzed in the 30 MeV/u^940)Ar+^(112,124)Sn reactions.Partial emission probability P_i of a certain species i is defined here展开更多
The angular distributions of intermediate mass fragments with charge numbers from 3 to 24 emitted in 30 MeV/u 40Ar+58,64Ni and 115In reactions over an angular range of 5o-140ohave been measured.In different angular re...The angular distributions of intermediate mass fragments with charge numbers from 3 to 24 emitted in 30 MeV/u 40Ar+58,64Ni and 115In reactions over an angular range of 5o-140ohave been measured.In different angular region an exponential distribution function dσ/dΩ=N exp(-θ/α)was used to fit the measured angular distributions.The decay factor a which can be connected with the interaction time T and the factor N which is related to the intensity of the emission sources have been extracted.The relationship ofα(Z)and N(Z)with Z for different reaction systems and different angular regions has been discussed.The different behavior of dσ/dΩ,α(Z),and N(Z)for the three studied reaction systems exists mainly in the middle and backward angular regions.The dependencies of angular distributions on isospin and the size of reaction systems have also been discussed.展开更多
Correlated fission fragments from the reaction of 25MeV/u ^(40)Ar+^(209)Bi and their further correlation with a par-tides have been studied for peripheral and central collisions simultaneously.The excitation energy at...Correlated fission fragments from the reaction of 25MeV/u ^(40)Ar+^(209)Bi and their further correlation with a par-tides have been studied for peripheral and central collisions simultaneously.The excitation energy at scission deduced from postscission multiplicity is about 1725 MeV.The fission timescale deduced from prescission multiplicity is about 4×10^(21)s.Systematic analysis of the mass and energy distributions of Hssion fragments as a function of the initial temperature of hot fissioning nuclei reveals the existence of different fission behavior of hot nuclei formed in central and peripheral collisions.Experimental data demonstrate the change of Hssion behavior at T~4MeV.展开更多
An inclusive measurement was performed for 30 MeV/u ^(40)Ar+^(58,64)Ni and ^(115)In.By employing the degree of freedom of N/Z,the production mechanism of the high energy component of the intermediate mass fragments(IM...An inclusive measurement was performed for 30 MeV/u ^(40)Ar+^(58,64)Ni and ^(115)In.By employing the degree of freedom of N/Z,the production mechanism of the high energy component of the intermediate mass fragments(IMFs:3≤Z≤13)has been discussed.Special attention has been paid to the target dependence of N/Z ratio of the energetic fragments.These IMFs may be produced by a projectile fragmentation process with energy dissipation.展开更多
Reaction time of the deeply inelastic reaction in 8.5MeV/u ^(84)Kr+^(27)A1 was estimated to be 8×10^(-21)s by extracting pre-scissionαand proton multiplicities and by statistical model(PACE4)calculations.By usin...Reaction time of the deeply inelastic reaction in 8.5MeV/u ^(84)Kr+^(27)A1 was estimated to be 8×10^(-21)s by extracting pre-scissionαand proton multiplicities and by statistical model(PACE4)calculations.By using this reaction time value,the diffusion model calculations for the charge number distribution of fragments nicely explained the experimental results for the reactions at three incident energies 5.8,8.5 and 10.6MeV/u.It is indicated that a considerable fission-like component has contributed to the symmetric splitting fragments in the reactions,especially at 8.5 and 10.6 MeV/u.展开更多
The particle-particle(P-P)correlation functions are investigated in 46.7MeV/u^(12)C induced reactions,the correlation functions are greatly enhanced at q~20 MeV/c when the sum of the energies of two correlated protons...The particle-particle(P-P)correlation functions are investigated in 46.7MeV/u^(12)C induced reactions,the correlation functions are greatly enhanced at q~20 MeV/c when the sum of the energies of two correlated protons are high and almost independent on the targets.On the contrast,a strongly target dependent effect is observed for the P-P correlation functions when the sum energies are low.展开更多
The 2n-removal cross sections of 20～40 MeV/u^6He on^(28)Si was measured at RIBLL.The secondary beam of^6He was produced by 60 MeV/u^(13)C primary beam bombarding^9Be target,separated and identified by using B_p,the w...The 2n-removal cross sections of 20～40 MeV/u^6He on^(28)Si was measured at RIBLL.The secondary beam of^6He was produced by 60 MeV/u^(13)C primary beam bombarding^9Be target,separated and identified by using B_p,the wedge degrader,TOF and△E~[1].展开更多
Measurement of the neutron yield is performed at a primary energy of 400 MeV/u carbons for the Pb target.Water-bath activation-foil method is used in a moderation measurement with Au foils to detect the moderated neut...Measurement of the neutron yield is performed at a primary energy of 400 MeV/u carbons for the Pb target.Water-bath activation-foil method is used in a moderation measurement with Au foils to detect the moderated neutrons. The neutron yield is determined to be 18.4±2.1 per carbon by integrating the neutron flux over the entire water volume. The corresponding simulation values are performed by Geant4 code with three models to compare with the experimental results. The comparison shows that the calculated result with the INCL model is in good agreement with the experimental data.展开更多
Knockout reactions at intermediate and high energies have been proved to be a powerful tool for probing thesingle-particle structure of rare isotopes[1]. The spectroscopic factors and orbital angular momenta of the re...Knockout reactions at intermediate and high energies have been proved to be a powerful tool for probing thesingle-particle structure of rare isotopes[1]. The spectroscopic factors and orbital angular momenta of the removednucleons can be deduced by comparison of the experimental cross sections and longitudinal-momentum distributionsto those calculated in the Glauber reaction theory. Recently, study shows that for strongly bound valence nucleonknockout, the experimental cross sections are much smaller than reaction theory predictions[2].展开更多
One-nucleon removal reactions at intermediate-and high-energies have been developed as an effective direct reaction for probing the structure of nuclei far from stability.The removal of two well-bound like nucleons fr...One-nucleon removal reactions at intermediate-and high-energies have been developed as an effective direct reaction for probing the structure of nuclei far from stability.The removal of two well-bound like nucleons from asymmetric nuclei has also been shown to proceed as a direct reaction,while in the case of two weakly-bound nucleon removal from a mass A projectile,the reaction mechanism is complicated.The mass A-2 residue can result from two different mechanisms[1,2]:single-step direct removal of a pair of nucleons and one-nucleon knockout to unbound states of the intermediate mass A-1 residue followed by nucleon evaporation.展开更多
Accelerator-Driven Systems(ADS)are one of the proposed options for the transmutation of long lived nuclides and minor actinid es based on spallation reaction.The creation and the accumulation of stable and radioactive...Accelerator-Driven Systems(ADS)are one of the proposed options for the transmutation of long lived nuclides and minor actinid es based on spallation reaction.The creation and the accumulation of stable and radioactive nuclides in the target material during the irradiation is a very important issue for safety concerns target handling and disposal after irradiation.展开更多
One-nucleon knockout reactions have been used to get spectroscopic factor information of unstable nuclei for decadesl[1-4],and a systematic analysis of experiment for intermediate energies of around 80 MeV/u knockout ...One-nucleon knockout reactions have been used to get spectroscopic factor information of unstable nuclei for decadesl[1-4],and a systematic analysis of experiment for intermediate energies of around 80 MeV/u knockout reactions based on the eikonal model indicates a strong isospin asymmetry dependence of the reduction of the extracted spectroscopic strength relative to the shell-model predictionsl[2,3].展开更多
Effects of cluster correlations on fragments emission in ^(12)C+^(12)C at 50 MeV/u are studied with the antisymmetrized molecular dynamics(AMD)and an extended version of AMD,which has introduced cluster correlation ba...Effects of cluster correlations on fragments emission in ^(12)C+^(12)C at 50 MeV/u are studied with the antisymmetrized molecular dynamics(AMD)and an extended version of AMD,which has introduced cluster correlation based on the original AMD version(AMD-cluster).For the simulations,AMD model contains no effects of cluster correlations.The experimental data are well reproduced by the AMD-cluster calculations for light charged particles with Z≤2(LCPs).The angle distributions of isotopes with Z>2(IMFs)are reproduced reasonably well by the AMD-cluster calculations.But the yields of ^(8)B,^(10)Be,^(10)C and ^(12)C do not improve.展开更多
The production of clusters in transport models is very important.Unfortunately,most transport models cannot describe clusters properly due to the assumption of single-nucleon motion in the mean field.In Refs.[1–3],th...The production of clusters in transport models is very important.Unfortunately,most transport models cannot describe clusters properly due to the assumption of single-nucleon motion in the mean field.In Refs.[1–3],the cluster correlations have been introduced in AMD approach by improving the two-nucleon collision process.In this work,the intermediate mass fragment production in 12C+12C reaction at 95 MeV/u is investigated using the AMD approach with the cluster correlation,coupled with Gemini++.展开更多
The separation and identification of isotopes emitted from the projectile fragmentation reaction of 80 MeV/u 20Ne on 9Be target were carried out by using the radioactive ion beam line in Lanzhou(RIBLL).Many proton ric...The separation and identification of isotopes emitted from the projectile fragmentation reaction of 80 MeV/u 20Ne on 9Be target were carried out by using the radioactive ion beam line in Lanzhou(RIBLL).Many proton rich isotopes are obtained.Their intensity and purity fit the theoretical calculations.Good separation and identification abilities of RIBLL A/ΔA>300 and Q/ΔQ>150,are obtained.展开更多
Breakup reactions of the double borromean nucleus ^(8)He were measured at 82.3 MeV/u on CH2 and C targets.The coincident detection of two decaying neutrons and the high performance for neutron cross talk rejection are...Breakup reactions of the double borromean nucleus ^(8)He were measured at 82.3 MeV/u on CH2 and C targets.The coincident detection of two decaying neutrons and the high performance for neutron cross talk rejection are realized in this experiment.The relative energy spectrum for ^(8)He was reconstructed with good statistics.The spectrum exhibits a structure of two resonant peaks,one at an excitation energy of about 3.0 and the other at about 4.14 MeV,respectively.Substantially larger cross section for the first resonance is observed in comparison to the results reported previously.展开更多
文摘Hot nuclei with differentN/Z ratio were produced by using^(40)Ar beam on^(112)Sn and^(124)Sn target,respectively.The energy spectra and the emission probabilities of hydrogen isotopes are analyzed in the 30 MeV/u^940)Ar+^(112,124)Sn reactions.Partial emission probability P_i of a certain species i is defined here
基金Supported by the National Natural Science Foundation of China under Grant No.19235012the Foundation of Chinese Academy of Sciences。
文摘The angular distributions of intermediate mass fragments with charge numbers from 3 to 24 emitted in 30 MeV/u 40Ar+58,64Ni and 115In reactions over an angular range of 5o-140ohave been measured.In different angular region an exponential distribution function dσ/dΩ=N exp(-θ/α)was used to fit the measured angular distributions.The decay factor a which can be connected with the interaction time T and the factor N which is related to the intensity of the emission sources have been extracted.The relationship ofα(Z)and N(Z)with Z for different reaction systems and different angular regions has been discussed.The different behavior of dσ/dΩ,α(Z),and N(Z)for the three studied reaction systems exists mainly in the middle and backward angular regions.The dependencies of angular distributions on isospin and the size of reaction systems have also been discussed.
基金Supported by the National Natural Science Foundation of China under Grant No.19235011.
文摘Correlated fission fragments from the reaction of 25MeV/u ^(40)Ar+^(209)Bi and their further correlation with a par-tides have been studied for peripheral and central collisions simultaneously.The excitation energy at scission deduced from postscission multiplicity is about 1725 MeV.The fission timescale deduced from prescission multiplicity is about 4×10^(21)s.Systematic analysis of the mass and energy distributions of Hssion fragments as a function of the initial temperature of hot fissioning nuclei reveals the existence of different fission behavior of hot nuclei formed in central and peripheral collisions.Experimental data demonstrate the change of Hssion behavior at T~4MeV.
基金Supported by the National Natural Science Foundation of China under Grant No.19205006.
文摘An inclusive measurement was performed for 30 MeV/u ^(40)Ar+^(58,64)Ni and ^(115)In.By employing the degree of freedom of N/Z,the production mechanism of the high energy component of the intermediate mass fragments(IMFs:3≤Z≤13)has been discussed.Special attention has been paid to the target dependence of N/Z ratio of the energetic fragments.These IMFs may be produced by a projectile fragmentation process with energy dissipation.
文摘Reaction time of the deeply inelastic reaction in 8.5MeV/u ^(84)Kr+^(27)A1 was estimated to be 8×10^(-21)s by extracting pre-scissionαand proton multiplicities and by statistical model(PACE4)calculations.By using this reaction time value,the diffusion model calculations for the charge number distribution of fragments nicely explained the experimental results for the reactions at three incident energies 5.8,8.5 and 10.6MeV/u.It is indicated that a considerable fission-like component has contributed to the symmetric splitting fragments in the reactions,especially at 8.5 and 10.6 MeV/u.
文摘The particle-particle(P-P)correlation functions are investigated in 46.7MeV/u^(12)C induced reactions,the correlation functions are greatly enhanced at q~20 MeV/c when the sum of the energies of two correlated protons are high and almost independent on the targets.On the contrast,a strongly target dependent effect is observed for the P-P correlation functions when the sum energies are low.
文摘The 2n-removal cross sections of 20～40 MeV/u^6He on^(28)Si was measured at RIBLL.The secondary beam of^6He was produced by 60 MeV/u^(13)C primary beam bombarding^9Be target,separated and identified by using B_p,the wedge degrader,TOF and△E~[1].
基金Supported by the National Natural Science Foundation of China under Grant Nos 11575267,11775284,11575289 and 11605258
文摘Measurement of the neutron yield is performed at a primary energy of 400 MeV/u carbons for the Pb target.Water-bath activation-foil method is used in a moderation measurement with Au foils to detect the moderated neutrons. The neutron yield is determined to be 18.4±2.1 per carbon by integrating the neutron flux over the entire water volume. The corresponding simulation values are performed by Geant4 code with three models to compare with the experimental results. The comparison shows that the calculated result with the INCL model is in good agreement with the experimental data.
文摘Knockout reactions at intermediate and high energies have been proved to be a powerful tool for probing thesingle-particle structure of rare isotopes[1]. The spectroscopic factors and orbital angular momenta of the removednucleons can be deduced by comparison of the experimental cross sections and longitudinal-momentum distributionsto those calculated in the Glauber reaction theory. Recently, study shows that for strongly bound valence nucleonknockout, the experimental cross sections are much smaller than reaction theory predictions[2].
文摘One-nucleon removal reactions at intermediate-and high-energies have been developed as an effective direct reaction for probing the structure of nuclei far from stability.The removal of two well-bound like nucleons from asymmetric nuclei has also been shown to proceed as a direct reaction,while in the case of two weakly-bound nucleon removal from a mass A projectile,the reaction mechanism is complicated.The mass A-2 residue can result from two different mechanisms[1,2]:single-step direct removal of a pair of nucleons and one-nucleon knockout to unbound states of the intermediate mass A-1 residue followed by nucleon evaporation.
文摘Accelerator-Driven Systems(ADS)are one of the proposed options for the transmutation of long lived nuclides and minor actinid es based on spallation reaction.The creation and the accumulation of stable and radioactive nuclides in the target material during the irradiation is a very important issue for safety concerns target handling and disposal after irradiation.
基金National Natural Science Foundation of China(11575257,U1732134,11305222)。
文摘One-nucleon knockout reactions have been used to get spectroscopic factor information of unstable nuclei for decadesl[1-4],and a systematic analysis of experiment for intermediate energies of around 80 MeV/u knockout reactions based on the eikonal model indicates a strong isospin asymmetry dependence of the reduction of the extracted spectroscopic strength relative to the shell-model predictionsl[2,3].
文摘Effects of cluster correlations on fragments emission in ^(12)C+^(12)C at 50 MeV/u are studied with the antisymmetrized molecular dynamics(AMD)and an extended version of AMD,which has introduced cluster correlation based on the original AMD version(AMD-cluster).For the simulations,AMD model contains no effects of cluster correlations.The experimental data are well reproduced by the AMD-cluster calculations for light charged particles with Z≤2(LCPs).The angle distributions of isotopes with Z>2(IMFs)are reproduced reasonably well by the AMD-cluster calculations.But the yields of ^(8)B,^(10)Be,^(10)C and ^(12)C do not improve.
文摘The production of clusters in transport models is very important.Unfortunately,most transport models cannot describe clusters properly due to the assumption of single-nucleon motion in the mean field.In Refs.[1–3],the cluster correlations have been introduced in AMD approach by improving the two-nucleon collision process.In this work,the intermediate mass fragment production in 12C+12C reaction at 95 MeV/u is investigated using the AMD approach with the cluster correlation,coupled with Gemini++.
基金Supported by the Chinese Academy of Sciencesthe National Committee of Science and Technology of China。
文摘The separation and identification of isotopes emitted from the projectile fragmentation reaction of 80 MeV/u 20Ne on 9Be target were carried out by using the radioactive ion beam line in Lanzhou(RIBLL).Many proton rich isotopes are obtained.Their intensity and purity fit the theoretical calculations.Good separation and identification abilities of RIBLL A/ΔA>300 and Q/ΔQ>150,are obtained.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11035001,10975006 and J1103206the National Basic Research Program of China under Grant No 2007CB815002.
文摘Breakup reactions of the double borromean nucleus ^(8)He were measured at 82.3 MeV/u on CH2 and C targets.The coincident detection of two decaying neutrons and the high performance for neutron cross talk rejection are realized in this experiment.The relative energy spectrum for ^(8)He was reconstructed with good statistics.The spectrum exhibits a structure of two resonant peaks,one at an excitation energy of about 3.0 and the other at about 4.14 MeV,respectively.Substantially larger cross section for the first resonance is observed in comparison to the results reported previously.
