【作者】 鲁彦霞；

【导师】 陈熙萌；

【作者基本信息】 兰州大学 ， 粒子物理与原子核物理， 2007， 博士

【摘要】 本工作是在兰州大学2×1.7MV串列加速器上完成的。对加速器产生的0.2-6.3MeV C^q+（q=1-4）和0.25-6.35MeV O^q+（q=1-4）与气体He、Ne、Ar原子碰撞的各种截面进行了研究。分析了中能区的俘获和电离机制，并进一步提出了极化模型。实验采用反冲离子飞行时间测量技术、散射离子位置灵敏探测技术和符合测量方法，得到了随散射离子与反冲离子电荷态分布的二维符合谱。通过Ne的多重电离绝对截面与多体蒙特卡罗模拟计算结果比较，分析了多重电离的机制，并研究了非全裸离子有效电荷对能量的依赖关系。通过O²⁺的双单电子损失截面比与多体蒙特卡罗计算结果比较，研究了碰撞过程中不同靶原子的平均有效电荷与速度的依赖关系。另外，通过一价反冲离子下的O²⁺的双单电子损失截面比的实验曲线验证了屏蔽和反屏蔽理论的正确性。研究了入射离子单电子损失下的He的电离情况，并利用屏蔽和反屏蔽理论加以分析。研究了不同入射离子、不同靶原子碰撞过程中入射离子双、单电子损失截面比随速度的变化规律，从电子布居和有效电荷方面进行了简单分析。在独立电子模型基础上，利用半经验方法，建立了较大能区适用的新的俘获和电离模型——极化模型。该模型可以同时进行俘获、电离和电子损失反应道耦合的最终出射道的绝对截面计算。通过计算与文献数据及本实验数据比较发现符合较好。更多还原

【Abstract】 This work was done at the 2><1.7MV tandem accelerator in Lanzhou University. Various ionization cross sections were investigated for 0.2-6.3MeV C^q+（q=l-4） and 0.25-6.35MeV O^q+（q=1-4） colliding with He, Ne, Ar atoms respectively. The mechanism of capture and ionization in this energy region was discussed, and a new model—Polarization Model was presented. The Time-of-Flight measurement for recoil ions, position-sensitive detecting technique for scattering ions, and coincidence technique were employed to obtain correlation spectra.The pure ionization cross sections of Ne were investigated and compared with the n-body classical-trajectory-Monte-Carlo（nCTMC） calculations.The loss cross sections of O²⁺ were investigated and the effective charges of He and Ar atoms were obtained via comparison of experimental results and nCTMC calculations.The ionization cross sections of He were investigated and interpreted in the screening-and-antiscreening theory regime.The dependence on velocity and target atomic number of C^q+ and O^q+ was investigated and analyzed briefly in terms of effective charge and residual electron.Based on the Independent-Electron-Model, Polarization Model was established using semi-empirical method. It can calculate absolute cross sections for cooperated many channels and acquires good agreement with experimental results.更多还原