84.0MeV^(16)O轰击^(238)U核的裂变碎片角关联的测量

Fission Fragment Angular Correlation in the Reaction Induced by 84.0MeV ^(16)O Bombarded ^(238)U

使用两块大面积位置灵敏双栅雪崩计数器,测量了84.0MeV^(16)O轰击^(238)U的裂变碎片角关联及角分布。用裂变碎片折叠角技术区分了熔合裂交反应中的复合核裂变和转移裂变的两种成份。在总裂变截面中,转移裂变的贡献约为10％。由于转移裂变碎片角分布的各向异性较小,扣除转移裂变贡献后,纯复合核裂变碎片各向异性提高5％左右。裂变碎片异性异常不可能仅仅来源于转移裂变的贡献。

Fission fragment angular distribution and angular correlation in the reaction induced by 84.0 MeV ^(16)O bombarded ^(238)U have been measured by using two position-sensitive PPAC with large area. Transfer fission has been removed from total fission using fission fragment angular correlation technique. The contribution to the total fission cross section arising from transfer is about 10%. The anisotropy of fission fragment for transfer-fission is rather small, thus the removal of the transfer fission has little effect on the total fragment angular distribution. Indeed the anisotropy becomes larger by about 5% and anomalously anisotropies still persist.