快重离子在聚合物潜径迹中引起的损伤效应研究

在室温和真空环境下利用不同的快重离子(1.158GeV Fe56、1.755GeV Xe136及2.636GeV U238)对多层堆叠的聚对苯二甲酸乙二醇酯(PET)、聚碳酸脂(PC)和聚酰亚胺(PI)进行了辐照,结合X射线衍射(XRD)、傅立叶红外光谱(FTIR)及紫外可见光谱测量技术,在较宽的电子能损(1.9-19.0 keV·nm-1)和注量范围(1×1010-6×1012 cm-2)研究了离子在不同聚合物潜径迹中引起的损伤过程,观测到了主要官能团的降解、炔基生成、非晶化及紫外吸收边缘的红移等现象随辐照注量及电子能损的变化趋势.通过对损伤过程的定量分析,应用径迹饱和模型假设,分别给出了Fe、Xe和U离子在不同电子能损下辐照PC时的平均非晶化径迹半径和炔基形成半径,并用热峰模型对实验结果进行了检验.     

辐射损伤潜径迹的纳米尺度观测研究

综述了近年来用扫描隧道显微镜 (STM )和扫描力显微镜 (SFM)在原子水平上观测辐射损伤潜径迹的研究及进展。详述了辐射损伤潜径迹的形貌、损伤范围、损伤数密度、损伤几率等 ,对损伤潜径迹直径与能损的关系、损伤过程及各种可能的损伤机制进行了分析和讨论。     

液态水中重离子径迹结构及能量沉积分布的研究

介绍了重离子径迹结构及能量沉积分布理论研究的进展情况，给出了重离子Ｍｏｎｔｅ Ｃａｒｌｏ计算模型以及电子径迹中的能量沉积几率分布和重离子径向剂量分布等计算结果。     

扫描力显微镜图象中离子潜径迹的表现形式

用扫描力显微镜（ＳＦＭ）观测高能重离子轰击云母样品造成朱零星戏迹在不同的ＳＦＭ图象中的表现形式，并探讨了针尖在表面扫描时摩擦力对ＳＦＭ图象中离子潜径迹反差的影响。     

快重离子电子能损引起的缺陷产生及其后续效应

快重离子与凝聚态物质相互作用是核物理研究的重要领域之一,近年不断有新的现象发现。文章综述了快重离子电子能损效应研究的历史和概况,重点介绍了快重离子辐照引起的缺陷产生和退火、潜径迹的形成、塑性形变、相变等现象以及相关理论模型,对该领域未来发展趋势给出展望。     

质子、α粒子在水蒸气中径迹结构的研究

本工作采用模拟粒子在水蒸气中输运的蒙特卡罗程序,模拟计算了0.3～5MeV质子、α粒子在水蒸气中的径迹结构,记录了相互作用位置的坐标、每次事件中的能量沉积以及相互作用的类型。程序中考虑了弹性散射、电离、激发、电荷转移等物理过程。研究得到了一些有益的结果,为进一步研究粒子致DNA辐射损伤的物理模型奠定了一定的基础。     

液态水中重离子径述结构及能量沉积分布的研究

介绍了重离子径述结构及能量沉积分布理论研究的进展情况，给出了重离子ＭｏｎｔｅＣａｒｌｏ计算模型以及电子径迹中的能量沉积几率分布和重离子径向剂量分布等计算结果。     

碳微集团束的产生及其在CR-39中径迹的AFM观测

在HI－13串行加速器上实现了对碳微集团的加速，得到了MeV级的碳微集团束，对产生的碳的微集团束进行了测量并用它对CR＝－39塑料核径迹探测器进行了辐照，利用先进的原子力显微镜对C1和C2在CR－39中的径迹进行了观测。     

C60薄膜在快重离子辐照下的结构稳定性研究

用傅立叶变换红外光谱、X射线衍射谱、X射线光电子谱和拉曼散射技术分析了能量为GeV量级的S、Fe、Xe、和U离子,以及120keV的H离子在室温下辐照多层堆积C60薄膜的结构稳定性,即快重离子在C60薄膜中由高密度电子激发引起的效应,主要包括C60分子的聚合、分子结构的损伤、新的高温-高压相的形成和晶态向非晶态的转变.     

Velocity effect of swift heavy ions in graphite studied by Raman spectroscopy

Highly oriented pyrolytic graphite (HOPG) samples were irradiated with swift heavy ions (Ar, Kr, Bi, U) of fluences between 10¹¹ and 10¹³ ions/cm² in energy range MeV-GeV. The irradiated samples were analyzed by Raman spectroscopy with laser wavelength of 532.2 nm. It is shown that the ratio between the integrated intensities of the disorder-induced D and the original G Raman bands which denotes the degree of the damage induced by ion irradiation increases as a function of ion fluence as well as the electronic energy loss. This agrees with the previous reports. However, quantitative analysis of the peak intensity at a fixed fluence discloses that ion velocity is also a significant parameter in determination of damage. The conclusion is that the extent of discontinuity of ion track may change with ion velocity besides the electronic energy loss. Considering the radial distribution of the energy deposited on the matter being velocity dependent, the energy density which combines the influence of the electronic energy loss and ion velocity may be more suitable for explaining the effect induced by swift heavy ions.     

荷电离子轰击靶材料损伤潜径迹的原子水平观测研究

叙述了用扫描隧道显微镜和原子力显微镜观测研究荷电离子轰击靶材料的损伤潜径迹的状况和进展，观测研究了Ａｕ离子和Ｈ＾＋轰击高定向石墨的ＳＴＭ。给出了损伤形貌、损伤范围、表面损伤数密度和离子注入剂量的关系，并对损伤过程进行了分析和讨论。     

Infrared study of astrophysical ice analogues irradiated by swift nickel ions

Water, carbon oxide, carbon dioxide, and ammonia ices are known to be pervasive constituents of the solar system and the interstellar medium. These ices and ice-covered surfaces are exposed to bombardment by energetic projectiles like photons, electrons, and ions. Laboratory experiments have been carried out to study the effects of such irradiation. However, there is a clear lack of information about the interaction of heavy ion components of solar/stellar wind and galactic cosmic rays (e.g. Fe) with ices in the keV to GeV energy range. The objective of this work is to study the effects produced in astrophysical ices by highly charged nickel ions at relatively high energy (∼50-500 MeV) in the electronic energy loss regime, and to compare them with those produced by protons, photons, and electrons. Our results for CO₂ and CO indicate that sputtering induced by heavy ions can be an important mechanism to desorb molecules in astrophysical environments.     

Atomic mixing in thin film systems by swift heavy ions

Because of their sensitivity to the electronic energy loss of swift heavy ions, we have investigated the high energy ion beam mixing of oxide layer systems. In this paper we present a summary of the results and first steps towards interpretation and modelling of the observed phenomena. As was also observed in the case of track formation, mixing was found to occur only if the electronic energy loss exceeds a threshold value. The threshold is determined by the less sensitive material, which is a clear hint that both sides of the interface must have been molten, to enable for effective interdiffusion. This interpretation is supported by the estimated interdiffusion constants which indeed lie in the range known for liquid state diffusion.     

Surface erosion induced by heavy ion backscattering analysis

Material removal induced by HIBS (Heavy Ion Backscattering Spectrometry) analysis has been investigated. For this purpose the thickness of thin metal films deposited on graphite was measured as a function of fluence of the Si and Ti projectile ion beam. Steady state erosion rates are in fair agreement with surface sputtering rates calculated by SRIM. For some layers however, the first few monolayers are removed at a much faster rate. A comparison with standard He RBS is made and consequences for the applicability of HIBS are discussed.     

Surface topography induced by swift heavy ion impacts

Classical molecular dynamics simulations have been carried out to investigate the development of surface topographies following irradiation by swift heavy ions. Two models were used: a thermal spike model in which atoms within a cylinder surrounding the path of the ion are given kinetic energy due to the electronic energy loss of the particle; and an electron stripping with recombination model. Both models give qualitatively similar results and show the formation of hillocks on the surface above the ion track and a less dense track core near to the surface.     

兰州重离子加速器辐照终端与快重离子辐照效应研究

介绍了兰州重离子加速器辐照终端的基本概况，并就可能开展的研究项目提出了建议。     

Interface mixing induced by swift heavy ions at metal-oxide/silicon interfaces

It was observed previously that ceramic/ceramic bilayers were very sensitive with respect to the electronic stopping power S_e, i.e. strong interface mixing, scaling with , occurred if a threshold S_ec was exceeded. The threshold seemed to be determined by the higher track formation threshold of two constituents forming the bilayer. Although no track formation has been observed in crystalline Si even for Uranium projectiles, interface mixing was observed previously for some Si-multilayers.

In this paper we report on the interface mixing of NiO, Fe₂O₃, TiO₂ on Si due to irradiation with 90–350 MeV Ar-, Kr-, Xe- and Au-ions at 80 K at fluences up to 9E15 ions/cm². Interface mixing, analyzed by means of Rutherford Backscattering Spectrometry (RBS), is found for these bilayers, too. But the threshold for intermixing is significantly higher compared to the ceramic/ceramic bilayers. This observation could be an evidence for the threshold being determined by the Si-layer. In contrast to NiO/Si and Fe₂O₃/Si, where an usual random walk mixing Δσ² = kΦ was observed, the interface broadening Δσ² for TiO₂/Si is found to scale nonlinearly with the ion fluence, which indicates that mixing is driven by a chemical solid-state reaction. At higher fluences plateaus form at the low energy Ni-edge of the RBS spectra. The plateaus indicate phase formation. X-Ray diffraction spectra does not show any evidence for new crystalline phases.     

Structural modifications induced by swift heavy ions in thin films of yttria fully stabilized zirconia

Among ceramic materials for nuclear waste containment, single crystal yttria fully stabilized zirconia (FSZ) gained particular consideration because of its excellent radiation resistance both in the elastic and inelastic collision regime. We deposited amorphous and polycrystalline, cubic FSZ thin films on (1 0 0) Si by ultraviolet pulsed laser ablation and irradiated them with swift heavy uranium ions of 2.6-GeV energy at fluences between 2 and 12 × 10¹¹ ions cm⁻². The films were characterized before and after irradiation using X-ray reflectivity, grazing incidence X-ray diffraction, micro-Raman spectroscopy and transmission electron microscopy. Under ion irradiation, as-deposited crystalline films undergo amorphisation, followed by partial recrystallisation, whereas as-deposited amorphous films retain their disordered character. The dominant defects produced in the films are oxygen vacancies which may explain the amorphisation to recrystallisation path of our crystalline films.