^(16)O+^(238)U垒下熔合裂变碎片角分布  

Fission-Fragment Angular Distributions for the ^(16)+^(238)U Near-and Sub-Barrier Fusion-Fission Reaction

作　　者：张焕乔[1] 刘祖华[1] 许谨诚[1] 阮明[1] 钱兴[1] 徐侃[1] 吕骏[1] 

机构地区：[1]中国原子能科学研究院,北京102413

出　　处：《高能物理与核物理》1992年第9期826-831,共6页High Energy Physics and Nuclear Physics

基　　金：国家自然科学基金

摘　　要：利用云母核径迹探测器测量了轰击能量从73.7—93.4MeV的^(16)O+^(238)U反应的裂变截面和碎片角分布。用考虑了核静态形变的Wong模型很好地重现了裂变激发函数,由此抽取了复合核的自旋分布。同时,利用裂变鞍点过渡态理论以抽取的自旋分布计算了裂变碎片角分布,表明碎片各向异性实验值大于理论值。此外实验揭示出,在低能区碎片各向异性随入射能量变化的走向不同于以前的测量结果。Fission cross sections and angular distributions have been measured for the ^(16)O+^(238)U reaction at bombarding energies from 73.7 to 93.7 MeV. The fission excitation function is well reproduced on the basis of Wong model. The fission-fragment angular distributions are calculated in terms of the transition-state theory, with the transmission coefficents extracted from the excitation function calculation. It is found that a discrepancy between the observations and the predictions in angular anisotropy of fission fragments exists at near-and sub-barrier energies. Moreover the tendency of the anistropies as a function of the center-of-mass energy aren't the same as previous measurement results.

关 键 词：裂变 截面 碎片 角分布 

分 类 号：O571.434[理学—粒子物理与原子核物理]