低能T_i^+注入棉花种子的深度-浓度分布的模拟计算

Simulation and Calculation of the Penetration Depth and Concentration Distribution for Titanium ions with Low Energy Implanted into Dry Cotton seed

国内许多单位开展了低能离子注入植物种子的实验研究,但在生物诱变机理方面却尚未有定论,其中低能离子注入植物种子的深度-浓度分布成为研究的一个焦点问题。许多人直接用LSS理论得到的TRIM程序,从理论上计算了低能重离子注入植物种子的深度-浓度的分布,却发现计算结果与实验测量结果相差甚远,于是得出LSS理论及TRIM程序不能直接用于计算离子注入非均匀、非致密、有孔道的植物种子这种特殊的靶材料的结论。针对这一研究课题,在目前尚未有更加成熟完善的理论模型和计算方法的前提下,为了便于计算,本文根据植物种子的结构特点,对靶材料棉花种子进行了处理,并对LSS理论进行了修正,用蒙特卡罗方法计算了初始能量为20keV的Ti+注入棉花种子的深度-浓度分布,得到了与实验结果符合较好的分布曲线,初步的确定了低能离子注入植物种子深度-浓度分布的一种理论计算方法。

Much experimental research into ions with low energy implanted into plant seeds has been conducted, yet the optimal mechanism to induce aberrance has not been found. One focus is depth-concentration distribution for ions with low energy implanted into the seeds. Many investigators have used LSS theory and the TRIM program directly to calculate the distribution of ions implanted into seeds but find that calculation results are not good for experimental results, so they conclude that LSS theory and TRIM program cannot be used directly for calculation of specific targets such as heterogeneous, incompact, loose and porous seeds. Aiming at this research task, we deal with these targets and correct LSS theory according to the distinguishing texture of plant seeds, using the Monte-Carlo method to calculate the penetration depth and concentration distribution for titanium ions with 20 keV energy implanted into dry cotton seed. We find a better curve, with calculation results from theory matched with those calculated by experimentation and preliminarily obtain a computational method about depthconcentration distribution for ions with low energy implanted into seeds.