近垒及垒下能区^(28)Si+^(174)Yb体系的裂变碎片质量分布  

Research of Fission Fragment Mass Distribution for ^(28)Si+^(174)Yb at Energies near the Coulomb Barrier

作　　者：王东玺 林承键[1] 贾会明[1] 杨峰[1] 徐新星[1] 杨磊[1] 马南茹[1] 孙立杰[1] 包鹏飞[1] 张焕乔[1] 刘祖华[1] 

机构地区：[1]中国原子能科学研究院,北京102413

出　　处：《原子核物理评论》2017年第3期534-538,共5页Nuclear Physics Review

基　　金：国家重点基础研究发展计划(973计划)项目(2013CB834404);国家自然科学基金资助项目(11375268;11475263;U1432246;U1432127;11505293;11635015)~~

摘　　要：使用两块大面积平行板雪崩计数器,测量了近垒及垒下^(28)Si+^(174)Yb熔合裂变碎片质量-角度关联分布及质量分布。质量-角度二维图显示在该反应能量区间内并没有发现明显的准裂变成分。运用单高斯曲线拟合了裂变碎片的质量分布并抽取了质量宽度。结果表明:在库仑势垒以上,质量宽度随着反应能量的升高而增大;在库仑势垒以下能区,发现质量宽度随着反应能量的降低而呈现轻微增大的趋势。运用鞍点统计模型对本次实验数据拟合发现,需用比文献给出的更大的刚度系数才能重现实验结果,其物理原因还需要进一步研究。In order to study the fission mechanism, the mass distributions and mass-angle distributions of the fission fragments for^（28）Si＋^（174） Yb were measured near the Coulomb barrier. The mass-angle correlations do not indicate any possible quasi-fission events in this bombarding energy range. The mass distributions were fitted by the single Gaussian distribution and then the mass widths were extracted. At above-barrier energies, the mass widths were found to increase with the energy. However, the mass widths show slight increase with decreasing energy below the barrier. Additionally, the mass widths can not be reproduced in the framework of the saddle statistic model with the given parameter, so further study is still needed.

关 键 词：熔合裂变 准裂变 裂变碎片质量分布 鞍点统计模型 

分 类 号：O571.53[理学—粒子物理与原子核物理]