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根据中能重离子束与靶物质相互作用的特点,提出了进行中能重离子束深度剂量分布计算的方法。与高能离子束中弹核碎裂为主要因素和低能离子束中能量歧离是惟一因素相比,中能离子束深度剂量分布的计算包括了随贯穿深度增加而增加的能量展宽和一个简单的弹核碎裂假设。计算了中能碳离子柬和氧离子束的相对深度剂量分布,并将它们同实验测量结果进行了比较,计算得到的Bragg曲线在Bragg峰的上游和下游与实验测量相符合。由于计算和实验条件的限制,Bragg峰区计算与实验结果出现了偏差,但在实验误差范围内计算值与实验测量值基本符合。细致分析了造成这一偏差的原因,并给出了由于这些原因带来偏差的幅度。
According to the characteristics of the interaction between heavy ion beam and target material, a method to calculate the depth dose distribution of heavy ion beam was proposed. Compared with the only factor that causes energy disintegration in low-energy ion beams, which is the major factor of the nucleus fragmentation in the high-energy ion beam, the calculation of the depth dose distribution of the intermediate energy ion beam includes the energy broadening that increases with the penetration depth and a simple Shell nuclear fragmentation hypothesis. The relative depth dose distributions were calculated and compared with the experimental measurements. The calculated Bragg curves are consistent with the experimental measurements upstream and downstream of the Bragg peaks. Due to the limitation of calculation and experimental conditions, the calculation of Bragg peak area deviates from the experimental result, but the calculated value agrees well with the experimental measurement value within the experimental error range. A detailed analysis of the causes of this deviation, and gives the extent of deviation due to these reasons.