35MeV／u^(36)Ar+^(112,124)Sn反应中中等质量碎片关联函数的入射道依赖  

Entrance Channel Dependence of the Correlation Function of IMFs in ^(36)Ar+^(112,124)Sn at 35MeV/u

作　　者：胡荣江[1] 肖志刚[1] 吴和宇[1] 段利敏[1] 王宏伟[1] 袁小华[1] 靳根明[1] 诸永泰[1] 李祖玉[1] 王素芳[1] 徐瑚珊[1] 张保国[1] 魏志勇[1] 冯兆庆[1] 付芬[1] 

机构地区：[1]中国科学院近代物理研究所,兰州730000

出　　处：《高能物理与核物理》2007年第4期350-356,共7页High Energy Physics and Nuclear Physics

基　　金：国家自然科学基金(10205020;19575055;10175081);国家重点基础研究发展规划项目(G2000077401);中国科学院知识创新工程方向性项目(KJCX2-SW-N18)资助~~

摘　　要：测量了35MeV／u36Ar+112,124Sn反应中小角关联出射的中等质量碎片(IMF)约化速度关联函数．结果表明36Ar+124Sn反应系统中的约化速度关联函数在小约化速度处的反关联程度比36Ar+112Sn反应系统中的强,表现出明显的入射道依赖性．考察出射粒子对的单核子总动量时,发现这种差异主要来自于高动量粒子对的贡献．用三体弹道理论模型MENEKA分别计算了两个系统的IMF发射时标,在36Ar+112Sn反应系统中约为150fm／c,而在36Ar+124Sn反应系统中,约为120fm／c．同位旋相关的量子分子动力学计算表明,36Ar+124Sn系统中IMF的发射时间谱比36Ar+112Sn系统略有前移,相应地,其中心密度从最高点随时间的下降亦比36Ar+112Sn系统略快．The reduced velocity correlation functions of the Intermediate Mass Fragments （IMFs） were measured in the reactions of ^36Ar＋^112,^124Sn at 35MeV/u. The anti-correlation at small reduced velocities is more pronounced in ^36Ar＋^124Sn system than that in ^36Ar＋^112Sn system. The difference of the correlation functions between the two reactions is mainly contributed by the particle pairs with high momenta. A three-body Coulomb repulsive trajectory code （MENEKA） is employed to calculate the emission time scale of IMFs for the both systems. The time scale is 150fm/c in the ^36Ar＋^112Sn system and 120fm/c in the ^36Ar＋^124Sn system, respectively. A calculation based on an Isospin dependence Quantum Molecular Dynamics code （IQMD） reveals that the emission time spectrum of IMFs is shifted slightly leftwards in ^36Ar＋^124Sn compared with that in the ^36Ar＋^112Sn system, indicating a shorter emission time scale. Correspondingly, the central density of the hot nuclei decreases faster in ^36Ar＋^124Sn than in ^36Ar＋^112Sn.

关 键 词：中等质量碎片 关联函数 发射时标 同位旋 

分 类 号：O571[理学—粒子物理与原子核物理]