DEFORMATION PATHS OF A NUCLEUS IN FISSION

核裂变的变形路径

• 批准号: 06452034
• 负责人: NAKAHARA Hiromichi
• 金额: $ 4.74万
• 依托单位: TOKYO METROPOLITAN UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1994
• 资助国家: 日本
• 起止时间: 1994 至 1996
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-06452034/
• 关键词: TWO DEFORMATION PATHS; PROTON-INDUCED FISSION; SYMMETRIC FISSION; ASYMMETRIC FISSION; ^<232>Th; ^<238>U; 2つのモード; ^<292>Th; 核分裂; 原子核の変形過程; 対称核分裂; 非対称核分裂; ^<232>陽子核分裂; 原子核分裂; 核の変形経路; 核分裂の多重経路

Two kinds of kinetic energy components were discovered present for the fission producing fission fragments of A=126-134 in proton induced fission of ^<232>th.In the present work, the incident energy dependence of the intensity of each of those two components was studied for proton-induced fission of ^<232>Th and ^<238>U by varying the proton energy from 12 to 16 MeV.The kinetic energies were carefully measured by the double TOF method. The time calibration of the time-of-flight system was performed using the 240 MeV ^<127>I beam from a tandem accelerator.The results clearly indicated that the intensity of the low kinetic energy component has the incident energy dependence similar to the mass yields of symmetric-mass-division products have while the intensity of high kinetic energy component behaves similarly to the yields of asymmetric-mass-division products.They lead to the conclusion that two deformation paths indeed exist in the low energy fission of light actinide : "one path experiences a higher fission barrier and ends up in symmetric mass division with the more elongated scission configuration, and the other goes over a lower fission barrier and leads to asymmetric mass division with more compact scission configuration.Those two deformation paths co-exist in the fission which produce fragments mass of 126 to 134.

在第 ^<232> 次质子诱发裂变中，发现了产生 A=126-134 裂变碎片的两种动能成分。在本工作中，这两种成分的强度与入射能量的相关性通过将质子能量从 12 MeV 改变到 16 MeV，研究了 ^<232>Th 和 ^<238>U 的质子诱导裂变。动能为采用双TOF法仔细测量。使用串联加速器发出的240 MeV^<127>I光束对飞行时间系统进行了时间校准。结果清楚地表明，低动能成分的强度与质量具有类似的入射能量依赖性对称分质产物的产率具有相同的性质，而高动能成分的强度与不对称分质产物的产率表现相似。他们得出结论，在低能裂变中确实存在两条变形路径。轻锕系元素：“一条路径经历较高的裂变势垒，最终以更细长的裂变构型形成对称质量分割，另一条路径越过较低的裂变势垒，导致具有更紧凑的裂变构型的不对称质量分割。这两条变形路径裂变中共存，产生质量为126至134的碎片。

项目成果

Y.Nagame, I.Nishinaka, K.Tsukada, Y.Oura, S.Ichikawa, H.Ikezoe, Y.L.Zhao, K.Sueki, H.Nakahara, M.Tanikawa, T.Ohtsuki, H.Kudo, Y.Hamajima, K.Takamiya, Y.H.Chung: "Two deformation paths in proton-induced fission of ^<232>Th." Physics Latters B. 387. 26-30 (

Y.Nagame、I.Nishinaka、K.Tsukada、Y.Oura、S.Ichikawa、H.Ikezoe、Y.L.Zhao、K.Sueki、H.Nakahara、M.Tanikawa、T.Ohtsuki、H.Kudo、Y.Hamajima

Y.Nagame et al.: "Two deformation paths in proton-indued fission of ^<232>Th" physics Letters B. 387. 26-30 (1996)

Y.Nagame 等人：“^<232>Th 质子引发裂变中的两条变形路径”物理学快报 B. 387. 26-30 (1996)

T.Ohtsuki: "Bimodal nature of actinide fission" J.Alloys and Compounds. (213)/(214). 423-425 (1994)

T.Ohtsuki：“锕系裂变的双峰性质”J.合金和化合物。

Y.Nagame et al.: "Two deformation paths in proton-lnduced fission of ^<232>Th" Physics Lettevs B. 387. 26-30 (1996)

Y.Nagame 等人：“^<232>Th 质子诱发裂变中的两个变形路径”Physics Lettevs B. 387. 26-30 (1996)