An E//B neutral particle analyzer(NPA)has been designed and is under development at Sichuan University and Southwestern Institute of Physics.The main purpose of the E//B NPA is to measure the distribution function of ...An E//B neutral particle analyzer(NPA)has been designed and is under development at Sichuan University and Southwestern Institute of Physics.The main purpose of the E//B NPA is to measure the distribution function of fast ions in the HL-2A/3 tokamak.The E//B NPA contains three main units,i.e.the stripping unit,the analyzing unit and the detection unit.A gas stripping chamber was adopted as the stripping unit.The results of the simulations and beam tests for the stripping chamber are presented.Parallel electric and magnetic fields provided by a NdFeB permanent magnet and two parallel electric plates were designed and constructed for the analyzing unit.The calibration of the magnetic and electric fields was performed using a 50 kV electron cyclotron resonance ion source(ECRIS)platform.The detection unit consists of 32lutetium-yttrium oxyorthosilicate(LYSO)detector modules arranged in two rows.The response functions ofα,hydrogen ions(H^(+),H_(2)^(+)and H_(3)^(+))andγfor a detector module were measured with^(241)Am,^(137)Cs and^(152)Eu sources together with the 50 kV ECRIS platform.The overall results indicate that the designed E//B NPA device is capable of measuring the intensity of neutral hydrogen and deuteron atoms with energy higher than 20 keV.展开更多
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
A Neutron Time-of-Flight(NTOF) spectrometer, based at the Heavy Ion Research Facility in Lanzhou(HIRFL) was developed for studies of neutron production of proton induced spallation reactions related to the ADS project...A Neutron Time-of-Flight(NTOF) spectrometer, based at the Heavy Ion Research Facility in Lanzhou(HIRFL) was developed for studies of neutron production of proton induced spallation reactions related to the ADS project. After the presentation of comparisons between calculated spallation neutron production doubledifferential cross sections and the available experimental data, a detailed description of the NTOF spectrometer is given. Test beam results show that the spectrometer works well and data analysis procedures are established.The comparisons of the test beam neutron spectra with those of GEANT4 simulations are presented.展开更多
The interaction between the supersonic molecular beam(SMB)and the low-temperature plasma is a critical issue for the diagnosis and fueling in the Tokamak device.In this work,the interaction process between the argon S...The interaction between the supersonic molecular beam(SMB)and the low-temperature plasma is a critical issue for the diagnosis and fueling in the Tokamak device.In this work,the interaction process between the argon SMB and the argon plasma is studied by a high-speed camera based on the Linear Experimental Advanced Device(LEAD)in Southwestern Institute of Physics,China.It is found that the high-density SMB can extinct the plasma temporarily and change the distribution of the plasma density significantly,while the low-density SMB can hardly affect the distribution of plasma density.This can be used as an effective diagnostic technique to study the evolution of plasma density in the interaction between the SMB and plasma.Moreover,the related simulation based on this experiment is carried out to better understand the evolution of electron density and ion density in the interaction.The simulation results can be used to analyze and explain the experimental results well.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 multiplicity of fragments in Fermi energy heavy-ion collisions was experimen- tally extracted. Compared with the results of calculation using the antisymmetrized molecular dynamics （AMD） model which accounts for...The multiplicity of fragments in Fermi energy heavy-ion collisions was experimen- tally extracted. Compared with the results of calculation using the antisymmetrized molecular dynamics （AMD） model which accounts for the primary fragments only, the results calculated using the AMD together with a statistical decay code GEMINI to account for the deexcitation of excited primary fragments are in better agreement with those extracted from the experiment. This observation indicates that the experimental multiplicity distribution may be significantly different from those of primary fragments.展开更多
A test result of a module for the collision centrality detector array （CCDA）, a simple detector array for the event classification of the centrality, is presented. The CsI（Tl） module has PMTs on both ends to read ...A test result of a module for the collision centrality detector array （CCDA）, a simple detector array for the event classification of the centrality, is presented. The CsI（Tl） module has PMTs on both ends to read out signals. The beam test results indicate that it provides a good light charged particles （LCP） identification and a reasonable energy resolution. The energy spectra of LCPs are compared with the GEANT simulation.展开更多
Traditionally,isoscaling has been interpreted and applied within the framework of the grand canonical ensemble,based on the assumption that fragment production occurs following the attainment of a statistical equilibr...Traditionally,isoscaling has been interpreted and applied within the framework of the grand canonical ensemble,based on the assumption that fragment production occurs following the attainment of a statistical equilibrium state.However,the influence of the symmetry energy can lead to differences in the neutron and density distribution in neutron-rich nuclei.This in turn may impact the iso scaling parameters(usually denoted byαandβ).We examine the isoscaling properties for neutron-rich fragments produced in highly asymmetric systems on inverse kinematics,namely^(40,48)Ca and ^(58,64)Ni+^(9)Be at 140 MeV per nucleon.We evaluate α and β values and sort them as a function of the neutron excess I≡N-Z.The significant differences in a extracted from fragments within different ranges of I emphasize the importance of understanding the dependence of isoscaling parameters on fragments generated in various collision regions.Furthermore,the|β(N)|/α(Z)value for a specific fragment in small size and highly iso spin asymmetry systems can serve as a probe to detect the variations in neutron density and proton density in different regions of the nucleus and indicate the limitations of theoretical models in investigating these issues.展开更多
基金supported by the National Magnetic Confinement Fusion Energy R&D Program of China(No.2018YFE0310200)National Natural Science Foundation of China(Nos.11705242,11805138 and 12175156)the Fundamental Research Funds for the Central Universities in China(Nos.YJ201820 and YJ201954)。
文摘An E//B neutral particle analyzer(NPA)has been designed and is under development at Sichuan University and Southwestern Institute of Physics.The main purpose of the E//B NPA is to measure the distribution function of fast ions in the HL-2A/3 tokamak.The E//B NPA contains three main units,i.e.the stripping unit,the analyzing unit and the detection unit.A gas stripping chamber was adopted as the stripping unit.The results of the simulations and beam tests for the stripping chamber are presented.Parallel electric and magnetic fields provided by a NdFeB permanent magnet and two parallel electric plates were designed and constructed for the analyzing unit.The calibration of the magnetic and electric fields was performed using a 50 kV electron cyclotron resonance ion source(ECRIS)platform.The detection unit consists of 32lutetium-yttrium oxyorthosilicate(LYSO)detector modules arranged in two rows.The response functions ofα,hydrogen ions(H^(+),H_(2)^(+)and H_(3)^(+))andγfor a detector module were measured with^(241)Am,^(137)Cs and^(152)Eu sources together with the 50 kV ECRIS platform.The overall results indicate that the designed E//B NPA device is capable of measuring the intensity of neutral hydrogen and deuteron atoms with energy higher than 20 keV.
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 National Natural Science Foundation of China(No.11075189)100 Persons Project(Nos.0910020BR0 and Y010110BR0)ADS Project 302 of the Chinese Academy of Sciences(No.XDA03030200)
文摘A Neutron Time-of-Flight(NTOF) spectrometer, based at the Heavy Ion Research Facility in Lanzhou(HIRFL) was developed for studies of neutron production of proton induced spallation reactions related to the ADS project. After the presentation of comparisons between calculated spallation neutron production doubledifferential cross sections and the available experimental data, a detailed description of the NTOF spectrometer is given. Test beam results show that the spectrometer works well and data analysis procedures are established.The comparisons of the test beam neutron spectra with those of GEANT4 simulations are presented.
基金National Natural Science Foundation of China(Grant Nos.11575121,11275133,and 11575055)the National Magnetic Confinement Fusion Program of China(Grant No.2014GB125004).
文摘The interaction between the supersonic molecular beam(SMB)and the low-temperature plasma is a critical issue for the diagnosis and fueling in the Tokamak device.In this work,the interaction process between the argon SMB and the argon plasma is studied by a high-speed camera based on the Linear Experimental Advanced Device(LEAD)in Southwestern Institute of Physics,China.It is found that the high-density SMB can extinct the plasma temporarily and change the distribution of the plasma density significantly,while the low-density SMB can hardly affect the distribution of plasma density.This can be used as an effective diagnostic technique to study the evolution of plasma density in the interaction between the SMB and plasma.Moreover,the related simulation based on this experiment is carried out to better understand the evolution of electron density and ion density in the interaction.The simulation results can be used to analyze and explain the experimental results well.
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supported by National Natural Science Foundation of China(No.11075189)the"Hundred Gifted Scientist Plam"of the Chinese Academy of Sciences(Nos.0910020BRO,Y010110BRO)
文摘The multiplicity of fragments in Fermi energy heavy-ion collisions was experimen- tally extracted. Compared with the results of calculation using the antisymmetrized molecular dynamics （AMD） model which accounts for the primary fragments only, the results calculated using the AMD together with a statistical decay code GEMINI to account for the deexcitation of excited primary fragments are in better agreement with those extracted from the experiment. This observation indicates that the experimental multiplicity distribution may be significantly different from those of primary fragments.
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.
文摘A test result of a module for the collision centrality detector array （CCDA）, a simple detector array for the event classification of the centrality, is presented. The CsI（Tl） module has PMTs on both ends to read out signals. The beam test results indicate that it provides a good light charged particles （LCP） identification and a reasonable energy resolution. The energy spectra of LCPs are compared with the GEANT simulation.
基金Supported by the National Natural Science Foundation of China(12375123,11975091)the Program for Innovative Research Team(in Science and Technology)in University of Henan Province(21IRTSTHN011),China。
文摘Traditionally,isoscaling has been interpreted and applied within the framework of the grand canonical ensemble,based on the assumption that fragment production occurs following the attainment of a statistical equilibrium state.However,the influence of the symmetry energy can lead to differences in the neutron and density distribution in neutron-rich nuclei.This in turn may impact the iso scaling parameters(usually denoted byαandβ).We examine the isoscaling properties for neutron-rich fragments produced in highly asymmetric systems on inverse kinematics,namely^(40,48)Ca and ^(58,64)Ni+^(9)Be at 140 MeV per nucleon.We evaluate α and β values and sort them as a function of the neutron excess I≡N-Z.The significant differences in a extracted from fragments within different ranges of I emphasize the importance of understanding the dependence of isoscaling parameters on fragments generated in various collision regions.Furthermore,the|β(N)|/α(Z)value for a specific fragment in small size and highly iso spin asymmetry systems can serve as a probe to detect the variations in neutron density and proton density in different regions of the nucleus and indicate the limitations of theoretical models in investigating these issues.
