Fission probes of sub-barrier fusion cross section enhancements and spin distribution broadening.
Fission probes of sub-barrier fusion cross section enhancements and spin distribution broadening.
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DOI：
10.1103/physrevc.34.1353
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发表时间：
1986-10
期刊：
影响因子：
--
通讯作者：
Murakami;Sahm;Vandenbosch;Leach;Ray;Murphy
中科院分区：
文献类型：
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作者：
Murakami;Sahm;Vandenbosch;Leach;Ray;Murphy
根据亚势垒轰击能量下/sup 12/C+ /sup 236/U和/sup 16/O+ /sup 232/Th反应的裂变碎片角分布，确定了复合核/sup 248/Cf的均方自旋值。的各向异性，因此，均方自旋值是远远大于预测的模型，再现的横截面增强中观察到的子势垒融合激发函数。一个类似的实验与球形目标/sup 208/Pb也导致更大的各向异性和均方自旋值比预测的各种融合模型，包括一个特别完整的耦合通道计算。补充的碎片碎片符合实验已经进行了较重的目标，以确认所观察到的裂变是与完整的动量转移。在两个角度测量了/sup 12/C+ /sup 236/U反应的质量分布，发现与角度无关。这最后一个结果表明，准裂变过程没有发挥重要作用。
The mean-square spin value of the compound nucleus /sup 248/Cf has been determined from fission fragment angular distributions for the /sup 12/C+ /sup 236/U and /sup 16/O+ /sup 232/Th reactions at sub-barrier bombarding energies. The anisotropy and hence the mean-square spin values are much larger than predicted by models which reproduce the cross section enhancement observed in the sub-barrier fusion excitation functions. A similar experiment with the spherical target /sup 208/Pb also leads to larger anisotropies and mean-square spin values than predicted by various fusion models, including an especially complete coupled channels calculation. Supplementary fragment-fragment coincidence experiments have been performed with the heavier targets to confirm that the observed fission is associated with full momentum transfer. The mass distribution for the /sup 12/C+ /sup 236/U reaction has been measured at two angles and found to be independent of angle. This last result suggests that quasifission processes are not playing a significant role.