Along with the development of the radioactive nuclear beam facility, the study of the structure of unstable nuclei has progressed rapidly over the last few decades. Due to the weakly binding property, the structure in...Along with the development of the radioactive nuclear beam facility, the study of the structure of unstable nuclei has progressed rapidly over the last few decades. Due to the weakly binding property, the structure information of the unstable nuclei comes primarily from the scattering or reaction experiments. Therefore it would be very important to understand clearly the reaction mechanism involved in the experiment. We outlined here the major reaction mechanisms which are adequate to the study of unstable nuclei, with the focus on the new phenomena and methods in comparison with those with traditional stable nucleus beam. Especially emphasized are the breakup and knockout reactions, developed as accurate tools for spectroscopy investigation into the nuclear structure with low intensity secondary beam. Couplings of the breakup channel to the elastic scattering and the fusion and transfer reactions are also reviewed.展开更多
The breakup reaction of ~9Li on a Pb target has been measured at 32.7 MeV/nucleon for the first time. Two peaks of ~6He+t coincident fragments at 9.8 and 12.5 MeV were observed and agreed with the results of the gener...The breakup reaction of ~9Li on a Pb target has been measured at 32.7 MeV/nucleon for the first time. Two peaks of ~6He+t coincident fragments at 9.8 and 12.5 MeV were observed and agreed with the results of the generator coordinate method calculation. The experiment was carried out thanks to a specially arranged detection system around zero degrees at the Heavy Ion Research Facility in Lanzhou, Radioactive Ion Beam Line in Lanzhou(HIRFL–RIBLL).展开更多
The breakup reactions of weakly-bound nuclei at energies around the Coulomb barrier and the cor- responding coupling effect on the other reaction channels are hot topics nowadays. To overcome the difficulty in identif...The breakup reactions of weakly-bound nuclei at energies around the Coulomb barrier and the cor- responding coupling effect on the other reaction channels are hot topics nowadays. To overcome the difficulty in identifying both heavier and lighter fragments simultaneously, a new kind of ionization-chamber based detector tele- scope has been designed and manufactured. It consists of a PCB ionization chamber and three different thickness silicon detectors installed inside the chamber, which form a multilayer △E-ER telescope. The working conditions were surveyed by using an a source. An in-beam test experiment shows that the detector has good particle identifi- cation for heavy particles like 17F and 160 as well as light particles like protons and alpha particles. The measured quasi-elastic scattering angular distribution and the related discussions for 17F＋208pb are presented.展开更多
The 17Ne nucleus is a possible candidate with a two-proton borromean halo structure. Since the theoretical model is diffcult to handle the three-body system, it is diffcult to determine the two-proton halo structure i...The 17Ne nucleus is a possible candidate with a two-proton borromean halo structure. Since the theoretical model is diffcult to handle the three-body system, it is diffcult to determine the two-proton halo structure in 17Ne. In the present research, we try to study the breakup reaction of 17Ne. For the Borromean nuclei, one-proton knockout results in an unstable nucleus which is decaying further by proton emission. This process will result in an angular correlation between the direction of the aligned recoiling unstable nucleus and its decay products. The angular correlations can give us information about the configuration of the valence proton in the 17Ne. Furthermore, theoretical calculations indicate that the momentum distributions of 16F c.m are sensitive to the structure of the halo in 17Ne. Thus the measurement of momentum distributions of 16F c.m may also give us conclusive information on the structure of 17Ne. The present experiment has been done at IMP in Lanzhou using the radioactive beam 17Ne at 30.8 MeV/u on a 43mg/cm2 12C target. The data analysis is under procedure and the primary results are provided.展开更多
In this paper, we investigate the breakup of spiral wave under no-flux, periodic and Dirichlet boundary conditions respectively. When the parameter ε is close to a critical value for Doppler-induced wave breakup, the...In this paper, we investigate the breakup of spiral wave under no-flux, periodic and Dirichlet boundary conditions respectively. When the parameter ε is close to a critical value for Doppler-induced wave breakup, the instability of the system caused by the boundary effect occurs in the last two cases, resulting in the breakup of spiral wave near the boundary. With our defined average order measure of spiral wave （AOMSW）, we quantify the degree of order of the system when the boundary-induced breakup of spiral wave happens. By analysing the AOMSW and outer diameter R of the spiral tip orbit, it is easy to find that this boundary effect is correlated with large values of R, especially under the Dirichlet boundary condition. This correlation is nonlinear, so the AOMSW sometimes oscillates with the variation of ε.展开更多
The experimental elastic cross section data of the projectile11 Be on target12 C at 49.3 Me V/nucleon energy is analysed. The calculations for the elastic scattering are performed by the phenomenological optical model...The experimental elastic cross section data of the projectile11 Be on target12 C at 49.3 Me V/nucleon energy is analysed. The calculations for the elastic scattering are performed by the phenomenological optical model. The different optical potentials to include breakup effects into the calculations, which are neutron+12C, neutron+10Be and10Be+12C, are described with the aid of the global potentials for neutron interactions and fitted to experimental data for the core and target interaction. Also, the first analysis of the optical model for10 Be on target12 C at 39.1 Me V is done for building the interaction potential of the core and the target for11 Be. For investigating the effects of the spectroscopic factors, obtained factors from the direct capture process using the nuclear level density are compared with the previous cross section and spectroscopic factor results. Obtained results for the elastic cross section reproduce the experimental data very well and show the requirement of including spectroscopic properties such as, spectroscopic factors and density of the excited states, to explain this elastic cross section data.展开更多
The studies of nuclear cluster structure play an important role in understanding of nuclear structure properties.There are lots of works have been done[1?6] to study the nuclear cluster structure properties.. It is a ...The studies of nuclear cluster structure play an important role in understanding of nuclear structure properties.There are lots of works have been done[1?6] to study the nuclear cluster structure properties.. It is a very importantmethod to investigate the nuclear cluster structure through analyzing the breakup reaction of the interesting nucleus.The experimental study of the cluster structure of 9Li through analyzing its breakup fragments was performed atRadioactive Ions Beam Line in Lanzhou (RIBLL). The light charged particles were measured by a ΔE-E telescopearray. Also the energy distribution of the fragments have been measured in this experiment.展开更多
基金supported by the National Basic Research Program of China(Grant No. 2007CB815002)the National Natural Science Foundation ofChina (Grant Nos. 11035001, 10775003,10827505 and 10821140159)the Fundamental Research Funds for the Central Universities of China
文摘Along with the development of the radioactive nuclear beam facility, the study of the structure of unstable nuclei has progressed rapidly over the last few decades. Due to the weakly binding property, the structure information of the unstable nuclei comes primarily from the scattering or reaction experiments. Therefore it would be very important to understand clearly the reaction mechanism involved in the experiment. We outlined here the major reaction mechanisms which are adequate to the study of unstable nuclei, with the focus on the new phenomena and methods in comparison with those with traditional stable nucleus beam. Especially emphasized are the breakup and knockout reactions, developed as accurate tools for spectroscopy investigation into the nuclear structure with low intensity secondary beam. Couplings of the breakup channel to the elastic scattering and the fusion and transfer reactions are also reviewed.
基金supported by the National Natural Science Foundation of China(Nos.U1432247 and 11575256)the National Basic Research Program of China(973 Program)(Nos.2014CB845405 and2013CB83440x)
文摘The breakup reaction of ~9Li on a Pb target has been measured at 32.7 MeV/nucleon for the first time. Two peaks of ~6He+t coincident fragments at 9.8 and 12.5 MeV were observed and agreed with the results of the generator coordinate method calculation. The experiment was carried out thanks to a specially arranged detection system around zero degrees at the Heavy Ion Research Facility in Lanzhou, Radioactive Ion Beam Line in Lanzhou(HIRFL–RIBLL).
基金Supported by National Key Basic Research Development Program of China(2013CB834404)National Natural Science Foundation of China(11375268,11475263,U1432127,U1432246)
文摘The breakup reactions of weakly-bound nuclei at energies around the Coulomb barrier and the cor- responding coupling effect on the other reaction channels are hot topics nowadays. To overcome the difficulty in identifying both heavier and lighter fragments simultaneously, a new kind of ionization-chamber based detector tele- scope has been designed and manufactured. It consists of a PCB ionization chamber and three different thickness silicon detectors installed inside the chamber, which form a multilayer △E-ER telescope. The working conditions were surveyed by using an a source. An in-beam test experiment shows that the detector has good particle identifi- cation for heavy particles like 17F and 160 as well as light particles like protons and alpha particles. The measured quasi-elastic scattering angular distribution and the related discussions for 17F＋208pb are presented.
基金Supported by National Natural Science Foundation of China (10775005, 10735010, J0730316)Chinese Major State Basic Research Development Program (2007CB815002)
文摘The 17Ne nucleus is a possible candidate with a two-proton borromean halo structure. Since the theoretical model is diffcult to handle the three-body system, it is diffcult to determine the two-proton halo structure in 17Ne. In the present research, we try to study the breakup reaction of 17Ne. For the Borromean nuclei, one-proton knockout results in an unstable nucleus which is decaying further by proton emission. This process will result in an angular correlation between the direction of the aligned recoiling unstable nucleus and its decay products. The angular correlations can give us information about the configuration of the valence proton in the 17Ne. Furthermore, theoretical calculations indicate that the momentum distributions of 16F c.m are sensitive to the structure of the halo in 17Ne. Thus the measurement of momentum distributions of 16F c.m may also give us conclusive information on the structure of 17Ne. The present experiment has been done at IMP in Lanzhou using the radioactive beam 17Ne at 30.8 MeV/u on a 43mg/cm2 12C target. The data analysis is under procedure and the primary results are provided.
基金Project supported by the Major Program of the National Natural Science Foundation for （Grant No 10335010） and the National Natural Science Foundation-the Science Foundation of China Academy of Engineering Physics （NSAF） （Grant No 10576005）. We are grateful to Professor Li Jing-Hui and Dr Yuan Guo-Yong for valuable discussion.
文摘In this paper, we investigate the breakup of spiral wave under no-flux, periodic and Dirichlet boundary conditions respectively. When the parameter ε is close to a critical value for Doppler-induced wave breakup, the instability of the system caused by the boundary effect occurs in the last two cases, resulting in the breakup of spiral wave near the boundary. With our defined average order measure of spiral wave （AOMSW）, we quantify the degree of order of the system when the boundary-induced breakup of spiral wave happens. By analysing the AOMSW and outer diameter R of the spiral tip orbit, it is easy to find that this boundary effect is correlated with large values of R, especially under the Dirichlet boundary condition. This correlation is nonlinear, so the AOMSW sometimes oscillates with the variation of ε.
基金Supported by the Turkish Science and Research Council(TBTAK)(No.112T566)
文摘The experimental elastic cross section data of the projectile11 Be on target12 C at 49.3 Me V/nucleon energy is analysed. The calculations for the elastic scattering are performed by the phenomenological optical model. The different optical potentials to include breakup effects into the calculations, which are neutron+12C, neutron+10Be and10Be+12C, are described with the aid of the global potentials for neutron interactions and fitted to experimental data for the core and target interaction. Also, the first analysis of the optical model for10 Be on target12 C at 39.1 Me V is done for building the interaction potential of the core and the target for11 Be. For investigating the effects of the spectroscopic factors, obtained factors from the direct capture process using the nuclear level density are compared with the previous cross section and spectroscopic factor results. Obtained results for the elastic cross section reproduce the experimental data very well and show the requirement of including spectroscopic properties such as, spectroscopic factors and density of the excited states, to explain this elastic cross section data.
文摘The studies of nuclear cluster structure play an important role in understanding of nuclear structure properties.There are lots of works have been done[1?6] to study the nuclear cluster structure properties.. It is a very importantmethod to investigate the nuclear cluster structure through analyzing the breakup reaction of the interesting nucleus.The experimental study of the cluster structure of 9Li through analyzing its breakup fragments was performed atRadioactive Ions Beam Line in Lanzhou (RIBLL). The light charged particles were measured by a ΔE-E telescopearray. Also the energy distribution of the fragments have been measured in this experiment.
