基于级联出射角关联函数的核时钟方法

A nuclear time scale method based on relative angle cognation function

建立了用出射运动学测量级联事件时间差的＂核时钟＂方法．不同级联出射道的粒子之间的互相作用，使出射粒子在出射的过程中改变出射方向．以质量对称三分裂为例，给出角关联函数谱的形状随出射粒子的发射时间差变化而变化．直接证明了２５ＭｅＶ／ｕＡｒ＋Ａｕ三裂变的级联出射断点时间差τ为～１０００ｆｍ／ｃ的结果，而６０ＭｅＶ／ｕ时τ为～１００ｆｍ／ｃ，给出了热核激发能升高、τ减小、从级联裂变到多重碎裂的演化。

A method of nuclear emission time scale based on analysing kinematics of sequential decay fragments has been established. Directions of eastted trajectories are varied with Coulomb interaction between fragments. The shapes of the relative angle correlation functions symmetric ternary fission for example, are changed with take difference τof emission, where τis a free parameter ranging from 0 to 2000fm/c. It is shown that the time scale reduces, with the increase of excitation energy for Ar+Au reactions, from ～1000fm/c at 25MeV/u to 50-100fm/c at 60MeV/u,and the mode of decay evolves from sequential to prompt.