高能Ar离子辐照PET引起的光吸收变化研究

采用紫外 -可见光吸收技术分析和研究了 35MeV/uAr离子辐照聚酯膜引起的光吸收改性 .结果表明 ,Ar离子轰击聚酯膜时引起了碳键的共轭体系形成 ,从而导致了紫外 -可见光区域中光吸收明显增加 ,光吸收增加的幅度依赖于离子的照射剂量、离子在样品中的平均电子能量损失以及光的波长 ,剂量越高 ,电子能损越大 ,光吸收增幅越大 ;而光的波长越长 ,光吸收的增加则越不明显 .利用测量到的光吸收曲线 ,同时还定量地研究了各种辐照条件下聚酯膜的光能隙和碳原子团的尺寸 .

25MeV/u~(40)Ar+~(115)In反应中前中角区碎片发射研究

从 2 5MeV/u4 0 Ar+115In反应前中角区出射碎片的能谱、角分布和Z电荷分布出发 ,讨论了碎片发射机制随出射角和核电荷数Z的渐进变化 ;用改进的量子分子动力学 (MQMD)模型研究了碎片角分布及Z电荷分布 ,理论计算和实验值整体上符合较好 ,但在前角区MQMD模型低估了碎片的产额 ,在中角区对于Z接近弹核的碎片 ,理论计算比实验值偏高 ;碎片产物的角分布及Z电荷分布还与统计模型GEMINI进行了比较 ,发现在前角区平衡蒸发的成分所占比例很小 ,中角区所占的比例有所增加 ,但仍然是较小的比例 .随着碎片核电荷数Z的减小 ,平衡核的蒸发成分逐渐减少 ,非平衡的中速成分逐渐占主导地位

红外光吸收研究35MeV/u Ar离子辐照半晶质聚酯膜引起的效应

３５ＭｅＶ／ｕ　Ａｒ离子在室温下辐照了多层堆叠的半晶质聚酯膜，采用傅立叶转换的红外光吸收技术分析和研究了由辐照引起的化学键断裂及其对离子剂量、离子在样品中的平均电子能量损失和吸收剂量的依赖性．结果表明，辐照导致聚酯膜中发生了明显的化学键断裂，断键过程主要发生在反式构型的乙二醇残留物和苯环的对位上，苯环的基本结构在辐照中变化较小．断键不仅强烈地依赖于离子的照射剂量，而且还跟样品中电子能量沉积密切相关，明显的断键发生在４．０ＭＧｙ以上的吸收剂量．

30 MeV/u~(40)Ar+~(nat)Ag反应中类弹碎片发射的时-空演化

报道了 ３０ＭｅＶ／ ｕ(４０)Ａｒ＋(ｎａｔ)Ａｇ反应中中等质量碎片（ＩＭＦ）发射时间（τ）随发射源空间大小的演化规律，并对类弹碎片的发射时空进行了讨论．结果表明，ＩＭＦ的发射时标与中等质量碎片关联函数以及发射源的核物质密度（ρ）有关，而与发射源的质量数的关系不大．对于能量较高的类弹碎片来说，在较小的核物质密度下提取的发射时间也较小，因此，在正常核物质密度参数下提取出的发射时间值可作为碎片实际发射时间的上限值．中速碎片的发射时间随密度大小的变化非常缓慢，提取出的发射时间值即可作为实际的发射时间。

25MeV/u ~(40)Ar+~(115)In,~(58)Ni,~(27)Al反应中前中角区碎片角分布和元素Z分布

测量了 ２５ＭｅＶ／ｕ４０　Ａｒ＋１１５　Ｉｎ，５８　Ｎｉ，２７　Ａ１反应前中角区出射碎片的角分布和 元素 Ｚ分布．用改进的量子分子动力学（ＭＱＭＤ）模型研究了碎片的角分布和 Ｚ 分布．理论计算值和实验值整体上符合得很好，但在前角区，ＭＱＭＤ模型低估 了碎片的产额，在中角区对于Ｚ接近弹核的碎片，理论计算值比实验值偏高．碎 片产物的角分布和Ｚ分布还与统计蒸发模型ＧＥＭＩＮＩ进行了比较，结果表明，在 前角区平衡蒸发成份所占的比例很小，中角区所占的比例有所增加，但仍然是较 小的比例．同时发现平衡蒸发成份随着出射碎片核电荷数Ｚ的减小而逐渐减 少．

Size modification of Au nanoparticles induced by slow highly charged ions Ar-40(q+) irradiation

Size modification of Au nanoparticles (NPs), deposited on the Au-thick film surface and irradiated by slow highly charged ions (SHCI) 40Arq+ (3 6 q 6 12) with fixed low dose of 4.3 1011 ions/cm2 and various energy ranging from 74.64 to 290.64 keV at room temperature (293.15 K), was investigated by atomic force microscopy (AFM) and transmission electron microscopy (TEM). The effect of projectile kinetic energy on the modified size of NPs was explored by an appropriate choice of the fixed process parameters such as ion flux, irradiation temperature, incident angle, irradiation time, etc. The morphological changes of NPs were interpreted by models involving collisional mixing, Ostwald ripening (OR) and inverse Ostwald ripening (IOR) of spherical NPs on a substrate. A critical kinetic energy as well as a critical potential energy of the projectile in the Au NPs size modification process were observed.

One-electron capture with simultaneous ionization in Cq+, Oq+ (q=1-4)-Ar collisions

The ratios R-k1 of k-fold to single ionization of the target atom with simultaneous one-electron capture by the projectile have been measured for 15-480 keV/u (nu(p) = 0.8-4.4 a.u.) collisions of Cq+, Oq+ (q=1-4) with Ar, using time-of-flight techniques which allowed the simultaneous identification of the final charge state of both the low-velocity recoil ion and the high-velocity projectile for each collision event. The present ratios are similar to those for He+ and He2+ ion impact. The energy dependence of R-k1 shows a maximum at a certain energy, E-max. which approximately conforms to the q(1/2)-dependence scaling. For a fixed projectile state, the ratios R-k1 also vary strongly with outgoing reaction channels. The general behavior of the measured data can be qualitatively analyzed by a simple impact-parameter, independent-electron model. (C) 2009 Elsevier B.V. All rights reserved.

Near infrared lights emission of Ar-40(16+) impacting on metal surfaces

The highly charged ion Ar-40(16+) with the velocity (kinetic energy E (K)=150 keV, velocity V=8.5x10(5) m/s) smaller than Bohr velocity (V (Bohr)=2.9x10(6) m/s) was found to hove impacts on the surfaces of metals Ni, Mo, Au and Al, and the Ar atomic infrared light lines and X-rays spectra were simultaneously measured. The experimental results show that the highly charged ion that captures electrons is neutralized, and the multiply-excited hollow atom forms. The hollow atom cascade decay radiates lights from infrared to X-ray spectrum. The intensity of infrared lights shows that the metallic work functions play an important role in the neutralization process of highly charged ions during their interaction with metallic surfaces, which verifies the classical over-the-barrier model.