用于垒下重离子熔合裂变研究的两维位置灵敏探测器

描述了用于近垒和垒下重离子熔合裂变实验的主要探测器——两维位置灵敏雪崩室(BPAC)的结构、工作原理及性能.给出了利用 BPAC 探测到的84MeV(E_(cm))~(16)O+~(232)Th 反应中不同碎片角区的碎片折叠角分布,并从中区分了转移裂变和复合核裂变的碎片角分布.从而证明转移裂变不是导致碎片角分布各向异性异常的原因.同时,实验结果支持了预平衡裂变模型对碎片角分布异常现象的解释.The structure,operation principle and performance of the bi-dimension position sensi- tive avalanche chamber (BPAC) used in the study of fusion fission induced by heavy ions at the near and sub-Coulomb barrier energy region are described. The fold angle distribution of fragments in different angle region for 84MeV (E_(cm))~(16)O+ ~(232)Th reaction system was obtained by using BPAC,from which the angle distribution of transfer-fission fragments has been distinguished from that of compound mucleus fission fra..

~（16）O＋~（nat）S全熔合激发函数

在入射能量为５５—７５ＭｅＶ的范围内，借助于位置灵敏的△Ｅ－Ｅ望远镜系统测量了（１６）Ｏ＋ｎａｔＳ反应的全熔合激发函数并做了讨论分析，提取了模型参数．激发函数存在着粗结构，其峰位分别为ＥｃＭ＝３８、４３、４８ＭｅＶ．The complete fusion excitation function for the 16O + natS reaction has been measured in the range of 50-75 MeV with a step of 1.0MeV by using 1a position sensitive △E-E telescope system. The model parameters have been extracted from data analysis.The striking gross structure of the excitation function has been observed. The energies of peaks are at EcM = 38,43 and 48 MeV respectively.中国科学院七五重大课题,中国科学基

~（16）O＋~（24）Mg反应全熔合激发函数的类共振结构

本工作用位置灵敏的△Ｅ－Ｅ望远镜系统，入射能量步长为１．０ＭｅＶ，测量了５５～９０ＭｅＶ~（１６）Ｏ＋~（２４）Ｍｇ反应全熔合激发函数．实验结果表明，这个反应的全熔合激发函数不是平滑的，存在着宽结构．峰位在Ｅ＿ＣＭ＝３４．２、３７．８、４０．６、４３．８和４６．６ＭｅＶ．当Ｅ＿ＣＭ＞４８ＭｅＶ时，激发函数的结构消失了。The complete fusion excitation function for the 16O+24Mg reaction has been measured in the energy range of 55～90MeVwith the step of 1.0MeV using a position sensitive△E-E telescopy system. It shows that the fusion excitation function is not smooth and exhibits gross structure. Peaks are at ECM=34. 2, 37. 8,40. 6,43. 8 and 46. 6MeV. The resonancestructure of the excitation function vanishes when ECM is>48.0MeV.中国科学院七五重大课题,中国科学院科学基

~(16)O+~(12)C反应全熔合激发函数的测量

我们用位置灵敏的ΔE-E望远镜系统测量了入射能量为50—90MeV范围内的~(16)O+~(12)C反应全熔合截面,发现全熔合激发函数是不平滑的,存在着一些结构,其峰位约在26.0,31.0和36.4MeV。对实验结果进行了分析和讨论,并与前人的工作进行了比较