摘要
使用离线γ测量技术在实验室系２８．３ＭｅＶ至４５．７ＭｅＶ的能区首次测量了１２Ｃ＋９３Ｎｂ反应产生的８个核素及同质异能态的激发函数．使用包括非弹性激发和α转移道的简单耦合道模型，结合统计蒸发程序对实验结果进行拟合．计算结果能较好地重现强截面的中子蒸发道（ｘｎ）的激发函数．而对于弱的质子（ｘＰｙｎ）特别是α粒子（ｘαｙｎ）蒸发道的截面，实验测量明显高于模型计算结果．α转移道与入射道耦合作为熔合反应的门庭态使垒下能区重离子熔合截面有很大的加强，实验测量与理论计算的比较表明对于１２Ｃ＋９３Ｎｂ反应系统在垒下能区可能存在着很强的α转移截面．
Cross sections for 8 products from the fusion reaction 12C+93Nb in the projectile energy range from 28.3 to 45.7 MeV have been obtained by off-line γ technique.The experimental results have been analysed in terms of the simplified coupledchannel model, including the coupling of the inelastic excitation and transfer channels, and statistical model for the compound nuclei. As a result, the excitation functions for the neutron emission channels are well reproduced by the CASCADE code. In the case of proton, alpha emission channels show higher cross sections than the CASCADE predictions. The transfer of alpha particles as doorways to fusion seems to be the main process which is responsible for the fusion enhancement. The experiment shows that the reaction system has large transfer cross section at subbarrier energy.
出处
《高能物理与核物理》
CSCD
北大核心
1995年第7期603-611,共9页
High Energy Physics and Nuclear Physics
基金
核工业总公司科学基金
关键词
近垒
垒下
重离子熔合
蒸发剩余核截面
heavy-ion fusion at near-and sub-barrier energies, cross sections of evaporation residues, statistical evaporation model, coupled-channel model.
