降能片对^(12)C^(6+)束流影响的Geant4模拟

Effect of Range Shifter to ^(12)C^(6+) Beam Simulated via Geant4 Method

利用Geant4模拟每核子能量在80~360 MeV内碳离子束(12 C6+)穿过靶质量厚度为0.5~4.0g/cm2的有机玻璃、铝、铜和铅后的角度歧离值和能量歧离值,并对比单能碳离子束直接进入水中和经降能片后再进入水中的Bragg峰.模拟结果表明:碳离子束的能量越高、降能片的质量厚度和原子序数越小,碳离子束经过降能片后的角度歧离和能量歧离值越小,其Bragg峰所受影响也越小.即若仅考虑角度歧离和能量歧离,则低原子序数的材料更适合做降能片.

The angle straggling and energy straggling of 12 C6＋ beam were simulated with method of Geant4.And the energy of 12 C6＋beam ranged from 80 MeV to 360 MeV per nucleon,while the mass thickness of the target,PMMA,Al,Cu,Pb,ranged from 0.5 g/cm2 to 4.0 g/cm2 .Besides,the Bragg peak of 12 C6＋ beam which have passed through range shifter was compared to the Bragg peak of mono-energetic 12 C6＋ beam.The results of the simulation show that the energy of 12 C6＋ beam is higher,the thickness and atomic number of the target is lower,then the angle and energy straggling of 12 C6＋beam after range shifter is lower,the effect of its Bragg peak is minimal.So,in the case of only consider the angle and energy straggling,the target of lower atomic number is more suitable for range shifter.