In this paper, we studied the process of dissociation unimolecular of the evaporation of H+2n+1 hydrogen clusters according to size, using the Rice-Ramsperger-Kassel-Marcus (RRKM) theory. The rate constants k(E) were ...In this paper, we studied the process of dissociation unimolecular of the evaporation of H+2n+1 hydrogen clusters according to size, using the Rice-Ramsperger-Kassel-Marcus (RRKM) theory. The rate constants k(E) were determined with the use of statistical theory of unimolecular reactions using various approximations. In our work, we used the products frequencies instead of transitions frequencies in the calculation of unimolecular dissociation rates obtained by three models RRKM. The agreement between the experimental cross section ratio and calculated rate ratio with direct count approximation seems to be reasonable.展开更多
The potential of the high resolution nuclear track detector (NTD) CR-39 is examined carefully for the measurement of relativistic nuclear projectile fragmentation cross sections and studies of related processes using ...The potential of the high resolution nuclear track detector (NTD) CR-39 is examined carefully for the measurement of relativistic nuclear projectile fragmentation cross sections and studies of related processes using the experience of many years of such measurements. The charge resolution and the charge resolving power of CR-39 detectors for the measurements of 158 A GeV 207Pb projectiles and their fragments are presented. Exposures of target-detector stacks, the chemical etching procedure and the nuclear track measurements are described in detail discussing precautions and possible errors. The procedures discussed are also valid for other NTDs. A comparison with electronic active detectors is also made considering important detection and measurement aspects. An experimental design proposing the co-use of NTDs with in-use active detectors is described.展开更多
本文对最高能量为500 A MeV的^(40)Ar与铜靶作用弹核碎裂电荷变化总截面及碎片产生分截面进行了实验研究,并与相近能区^(40)Ar诱发铜靶核碎裂的实验结果及理论模型计算结果进行了比较.结果表明:电荷变化总截面与相近能区实验结果一致,也...本文对最高能量为500 A MeV的^(40)Ar与铜靶作用弹核碎裂电荷变化总截面及碎片产生分截面进行了实验研究,并与相近能区^(40)Ar诱发铜靶核碎裂的实验结果及理论模型计算结果进行了比较.结果表明:电荷变化总截面与相近能区实验结果一致,也与Bradt-Peters及Nilsen半经验公式预言一致;NUCFRG2和PHITS模型预言低于实验结果.弹核碎片产生分截面在所研究的能区范围与束流能量没有明显依赖关系,EPAX3及FRACS半经验参数化公式可以较好地再现实验结果.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
The cross sections for 59,60Ca, recently measured in the 345 A MeV 70Zn+9 Be reaction,were estimated using the FRACS parametrization and an empirical formula,which are in good agreement.The FRACS parametrization and t...The cross sections for 59,60Ca, recently measured in the 345 A MeV 70Zn+9 Be reaction,were estimated using the FRACS parametrization and an empirical formula,which are in good agreement.The FRACS parametrization and the empirical formula are combined to predict the cross sections for extreme calcium isotopes 66,70Ca in the70,80Zn+9 Be reactions at the incident energies of 60,80,and 345 A MeV.The dependence of emperical formula parameters on the reaction system,as well as the incident energy,are discussed.The results indicate that 66,70Ca can be discovered in reactions of 60,80A MeV 80Zn+9 Be.The predicted binding energy for extreme neutron-rich isotopes by the spherical relativistic continuum Hartree-Bogoliubov theory was adopted in the calculation.Hence,the planned Beijing Isotope-Separation-On Line Neutron-Rich Beam Facility(BISOL),which is a third generation radioactive ion beam facility,could provide the opportunity to discover 66,70 Ca and neighboring neutron-drip line nuclei.展开更多
本文对最高束流能量为290 A MeV的^(12)C核诱发铝靶核反应射弹碎裂电荷变化反应总截面及碎片粒子产生分截面进行研究.结果显示射弹碎裂电荷变化总截面及碎片粒子产生分截面在误差范围内与束流能量无关,核碎裂电荷变化总截面计算结果与Br...本文对最高束流能量为290 A MeV的^(12)C核诱发铝靶核反应射弹碎裂电荷变化反应总截面及碎片粒子产生分截面进行研究.结果显示射弹碎裂电荷变化总截面及碎片粒子产生分截面在误差范围内与束流能量无关,核碎裂电荷变化总截面计算结果与Bradt-Peter公式及PHITS,NUCFRG2理论模型预测值一致,碎片粒子产生分截面值与NUCFRG2理论模型预测值一致.展开更多
Cross section production is one of the observable quantities in the hadronic systems. Inclusive cross section production J/ψ may be calculated through the use of the fragmentation c → J/ψ. In this paper we calculat...Cross section production is one of the observable quantities in the hadronic systems. Inclusive cross section production J/ψ may be calculated through the use of the fragmentation c → J/ψ. In this paper we calculate the inclusive cross section production J/ψ about the pole of Z^0 in the e^+e^- annihilation, through the lowest order regim of perturbative of QCD ananlyticaly. The obtained results arrive an excellent agreement with the exprimental data to produce the inclusive cross section production c → J/ψ.展开更多
文摘In this paper, we studied the process of dissociation unimolecular of the evaporation of H+2n+1 hydrogen clusters according to size, using the Rice-Ramsperger-Kassel-Marcus (RRKM) theory. The rate constants k(E) were determined with the use of statistical theory of unimolecular reactions using various approximations. In our work, we used the products frequencies instead of transitions frequencies in the calculation of unimolecular dissociation rates obtained by three models RRKM. The agreement between the experimental cross section ratio and calculated rate ratio with direct count approximation seems to be reasonable.
文摘The potential of the high resolution nuclear track detector (NTD) CR-39 is examined carefully for the measurement of relativistic nuclear projectile fragmentation cross sections and studies of related processes using the experience of many years of such measurements. The charge resolution and the charge resolving power of CR-39 detectors for the measurements of 158 A GeV 207Pb projectiles and their fragments are presented. Exposures of target-detector stacks, the chemical etching procedure and the nuclear track measurements are described in detail discussing precautions and possible errors. The procedures discussed are also valid for other NTDs. A comparison with electronic active detectors is also made considering important detection and measurement aspects. An experimental design proposing the co-use of NTDs with in-use active detectors is described.
文摘本文对最高能量为500 A MeV的^(40)Ar与铜靶作用弹核碎裂电荷变化总截面及碎片产生分截面进行了实验研究,并与相近能区^(40)Ar诱发铜靶核碎裂的实验结果及理论模型计算结果进行了比较.结果表明:电荷变化总截面与相近能区实验结果一致,也与Bradt-Peters及Nilsen半经验公式预言一致;NUCFRG2和PHITS模型预言低于实验结果.弹核碎片产生分截面在所研究的能区范围与束流能量没有明显依赖关系,EPAX3及FRACS半经验参数化公式可以较好地再现实验结果.
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.
基金Supported by the National Natural Science Foundation of China(U1732135)Natural Science Foundation of Henan Province(162300410179)
文摘The cross sections for 59,60Ca, recently measured in the 345 A MeV 70Zn+9 Be reaction,were estimated using the FRACS parametrization and an empirical formula,which are in good agreement.The FRACS parametrization and the empirical formula are combined to predict the cross sections for extreme calcium isotopes 66,70Ca in the70,80Zn+9 Be reactions at the incident energies of 60,80,and 345 A MeV.The dependence of emperical formula parameters on the reaction system,as well as the incident energy,are discussed.The results indicate that 66,70Ca can be discovered in reactions of 60,80A MeV 80Zn+9 Be.The predicted binding energy for extreme neutron-rich isotopes by the spherical relativistic continuum Hartree-Bogoliubov theory was adopted in the calculation.Hence,the planned Beijing Isotope-Separation-On Line Neutron-Rich Beam Facility(BISOL),which is a third generation radioactive ion beam facility,could provide the opportunity to discover 66,70 Ca and neighboring neutron-drip line nuclei.
文摘本文对最高束流能量为290 A MeV的^(12)C核诱发铝靶核反应射弹碎裂电荷变化反应总截面及碎片粒子产生分截面进行研究.结果显示射弹碎裂电荷变化总截面及碎片粒子产生分截面在误差范围内与束流能量无关,核碎裂电荷变化总截面计算结果与Bradt-Peter公式及PHITS,NUCFRG2理论模型预测值一致,碎片粒子产生分截面值与NUCFRG2理论模型预测值一致.
文摘Cross section production is one of the observable quantities in the hadronic systems. Inclusive cross section production J/ψ may be calculated through the use of the fragmentation c → J/ψ. In this paper we calculate the inclusive cross section production J/ψ about the pole of Z^0 in the e^+e^- annihilation, through the lowest order regim of perturbative of QCD ananlyticaly. The obtained results arrive an excellent agreement with the exprimental data to produce the inclusive cross section production c → J/ψ.
