单晶YSZ的Xe+离子辐照效应研究

 200keV Xe⁺离子辐照使单晶YSZ由无色透明变成紫色透明，结果表明，能量为200keV，注量为1×10¹⁷cm^-22的Xe⁺离子辐照YSZ单晶产生的损伤高达350dpa，在损伤区产生高密度的缺陷，但仍然没有发生非晶化转变。吸收光谱测试结果表明，产生吸收带的注量阈值大约为10¹⁶cm^-2。注量为1×10¹⁶cm^-2和1×10¹⁷cm^-2的样品，吸收带峰值分别位于522nm和497nm。光吸收带可能与Zr阳离子最近邻的氧空位捕获电子形成的F型色心和Y阳离子近邻的氧离子捕获空穴形成的V型色心有关。     

单晶YSZ的Xe+离子辐照效应研究

200keV Xe+离子辐照使单晶YSZ由无色透明变成紫色透明,结果表明,能量为200keV,注量为1×1017cm-22的Xe+离子辐照YSZ单晶产生的损伤高达350dpa,在损伤区产生高密度的缺陷,但仍然没有发生非晶化转变。吸收光谱测试结果表明,产生吸收带的注量阈值大约为1016cm-2。注量为1×1016cm-2和1×1017cm-2的样品,吸收带峰值分别位于522nm和497nm。光吸收带可能与Zr阳离子最近邻的氧空位捕获电子形成的F型色心和Y阳离子近邻的氧离子捕获空穴形成的V型色心有关。     

Ar离子辐照单晶Si引起的顺磁缺陷研究

采用电子顺磁共振研究了112MeVAr离子50K以下的低温辐照的单晶Si中缺陷产生和退火效应.结果表明:Ar离子辐照Si引起了中性四空位(Si-P3心).非晶化区域等缺陷的形成,Si-P3心分布在电子能损起主导作用的辐照区域,并在200℃的退火温度消失,伴随着四空位的退火,复杂的空位团,如Si-P1心.Si-A11心等出现,并保持到较高的温度.孤立的非晶区域的完全再结晶发生在350℃左右的退火温度,理论估算表明低剂量Ar离子辐照Si产生的非晶区域的半径分布在16-20A之间,定性地讨论了结果.     

采用EPR谱和TEM对YSZ单晶辐照损伤的研究

 利用电子顺磁共振(EPR)谱和透射电子显微镜(TEM)研究了YSZ单晶的辐照效应。200 keV的Xe和400 keV的Cs离子注入［111］取向的YSZ单晶中,注量均为5×10¹⁶ cm^-2。EPR结果表明辐照产生了共振吸收位置g‖=1.989 和 g⊥=1.869、对称轴为［111］的六配位Zr³⁺顺磁缺陷。Cs辐照产生了比Xe 离子辐照多约150倍的六配位Zr³⁺顺磁缺陷。两种样品的剖面电子显微分析表明没有发现非晶化转变,但是Cs离子辐照的样品在损伤集中区域产生了密度较高的缺陷。因此,EPR谱和电子显微观察均说明在相同离位损伤(约160 dpa)的情况下,Cs离子辐照比Xe 离子辐照产生了更多的缺陷。造成这一现象的原因是Cs离子是化学活性的而Xe 离子却是惰性的。     

离子辐照对单晶Si中预注入B原子扩散的影响

室温下使用MeV能量级Si,F和O离子对5keV B离子预注入后的n-型单晶Si(100)进行了辐照,应用二次离子质谱仪测试分析了掺杂物B原子的分布剖面及其变化.结果表明,高剂量Si,F和O离子的附加辐照可以抑制热激活退火中B原子发生的瞬间增强扩散.在相同的辐照条件下,Si近表面区域中SiO₂层的存在更有助于限制B原子的瞬间增强扩散.结合卢瑟福沟道背散射分析和DICADA程序计算对实验结果进行了讨论.     

高能氩离子在聚苯乙烯中的电子能损效应研究

用1.4GeV氢离子对多层堆叠的厚约53m的聚苯乙烯薄膜在室温和真空条件下进行了辐照;对辐照后的样品进行了从红外到紫外的光吸收测量.测量结果显示,材料经高能红离子辐照后发生化学降解,降解过程强烈依赖于电子能损;在能量沉积密度很高的径迹芯中,分子主链和苯环均遭到破坏;在电子能损高于0.77keV/nm时有炔基产生.     

金属材料中高能重离子辐照效应的理论描述

简要介绍了高能重离子在金属材料中引起辐照效应的主要理论,特别是与电子能损引起的缺陷产生与演化、离子潜径迹形成、辐照相变以及各向异性塑性形变等效应相应的理论描述.     

金属材料中高能重离子辐照效应的理论描述

简要介绍了高能重离子在金属材料中引起辐照效应的主要理论 ,特别是与电子能损引起的缺陷产生与演化、离子潜径迹形成、辐照相变以及各向异性塑性形变等效应相应的理论描述.Experimental results showed that, for high energy heavy ion irradiations, electronic energy loss could play a dominant role in damage process in solid materials. In order to explain the experimental phenomena and results, a series of theoretical models based on Coulomb explosion or thermal spike mechanisms have been proposed. In the present paper, more attention was paid to theoretical expressions of high energy heavy ion irradiation induced effects in metallic materials ...     

重离子诱导的质粒DNA双链断裂分布研究

利用能量为7．2MeV／u氖离子束辐照体外质粒DNA:pUC18，采用恒场凝胶电泳结合多功能荧光成像系统研究了pUC18双链断裂片段的分布。证实了双链断裂片段分布的非随机性，结果还发现DNA断裂后片段的交联现象，而且交联片段的分布也是非随机的。DNA is considered to be the most important and sensitive target in biological systems. In addition to the base damage, DNA strand breaks are the major lesion in the genome due to exposure to ionizing radiation. Mutation can be introduced to DNA as a result of enzymatic processing of DNA lesions or post irradiation replication. However, the mechanisms of radiation induced mutations are not well clarified at the molecular level. To study the effect on the simple plasmid DNA of heavy ion is even predominant or more feasible. Plasmid pUC18 DNA was prepared and irradiated by neon beam (7.199 MeV/u). The fragment distributions were determined by quantifying the ethidium bromide fluorescence. It can be seen that the shape of the intensity distributions is vastly different for the used radiation Dose. The distribution produced shows an excess of fragments particularly in 3 000 and 10 000 Gy the size range between 20—40 kbp and 20—50 bp. This clustering of double stranded fragments might be influenced by the higher order chromatin structure of genomic DNA. If so, DNA loop structures could correspond to the size range for which we observed DSB clustering. Further studies aim at elucidating the heterogeneity of DSB induction within the genome and investigate the influence of chromatin structure on the non random fragment distribution.     

钨辐射损伤随辐照剂量变化的重离子辐照模拟研究

采用重离子辐照模拟方法和正电子湮没寿命测量技术研究了钨辐射损伤随辐照剂量的变化。20,60和90dpa（每个原子的位移次数）辐照损伤水平的实验结果表明,辐照在钨中产生单空位、双空位、位错和空位团等缺陷;随辐照剂量的增大,单空位、双空位和位错浓度增加,空位团的尺度和浓度都随之增大。Radiation damage in W has been studied as a function of irradiation dose by heavy ion simulation and positron annihilation lifetime measurement. The experimental results of 20, 60 and 90 dpa irradiations illustrate that the mono-and di-vacancies, dislocations and vacancy clusters are produced by the irradiation. The concentrations of the mono-and di-vacancies and dislocations and both the concentration and size of the vacancy clusters or voids all increase with the increasing of the irradiation dose.     

94MeV Xe离子辐照引起的薄膜硅光学带隙变化研究

室温下,用94MeV的Xe离子辐照纳米晶和非晶硅薄膜以及单晶硅样品,辐照量分别为1.0×1011,1.0×1012和1.0×1013ions/cm2。所有样品均在室温下用UV/VIS/NIR光谱仪进行检测分析。通过对比研究了纳米晶、非晶、单晶硅样品的光学带隙随Xe离子辐照量的变化。结果表明,不同结构的硅材料中Xe离子辐照引起的光学带隙变化规律差异显著:随着Xe离子辐照量的增加,单晶硅的光学带隙基本不变,非晶硅薄膜的光学带隙由初始的约1.78eV逐渐减小到约1.54eV,而纳米晶硅薄膜的光学带隙则由初始的约1.50eV快速增大至约1.81eV,然后再减小至约1.67eV。对硅材料结构影响辐照效应的机理进行了初步探讨。     

Modification of Zinc-Implanted Silicon by Swift Xenon Ion Irradiation

50 keV ⁶⁴Zn⁺ ions to a dose of 5 × 10¹⁶ cm^–2 are implanted into substrates of single-crystal n-type silicon. Then the samples are irradiated at room temperature with 167 MeV ¹³²Xe²⁶⁺ ions with a fluence ranging from 1 ×10¹² up to 5 × 10¹⁴ cm^–2. Changes in the structure and properties on the sample surface and in its body are studied by scanning electron microscopy, energy dispersive microanalysis, atomic force microscopy, time-of-flight secondary ion mass spectrometry, and photoluminescence.     

硅微条探测器的辐射损伤试验

测量了硅微条探测器在辐照前后的坪曲线、脉冲高度与偏置电压的关系，及辐照后的总漏电流和黑洞的大小.     

Sub-wavelength Ripple Formation on Silicon Induced by Femtosecond Laser Radiation

Periodic microstructures on silicon bulk axe formed by the irradiation of the femtosecond laser with the laser wavelength of 800 nm and the pulse length of 130 fs. We investigate the surface periodic ripple structures produced by femtosecond laser treatment. The effects of feedrate of sample, v, on laser-induced surface topography are studied. We find that the femtosecond laser produce periodic ripples of the sub-micron level on silicon surface. At the same time, we realize the optimal conditions to produce these surface structures. When choosing NA = 0.3, and v = 2000μm/s or 3000μm/s, we find a series of periodic-structure ripples where the spacing is about 120 nm and the width is about 45nm. The experimental results indicate that femtosecond laser treatment can produce line arrays on the sub-micron level, which is a positive factor for fabricating grating and other optical applications in nanoscales.     

Atomic Mixing Induced by Ion Irradiation of V/Cu Multilayers

Bulk Cu/V multilayers simultaneously possess high strength and excellent radiation resistance thanks to their high density of interfaces.Irradiation-induced atomic mixing of Cu/V multilayers has been less investigated.Here,we investigate the ion irradiation of bulk Cu/V multilayers exposed to H_2~+ or He~+ ions at 350℃.The microstructure and elemental distribution are investigated by transmission electron microscopy and energy dispersive x-ray spectroscopy.Facetted bubbles and atomic mixing are observed after ion irradiation.The possible mechanisms of irradiation-induced atomic mixing are discussed.     

吸收杂质热辐射诱导光学薄膜破坏的热力机制

光学元件的破坏是限制高功率激光系统发展的主要问题,理解光学元件的破坏机制对于高功率激光系统的设计、运行参量选择以及器件技术发展有重要影响.以热辐射模型为基础研究了杂质吸收诱导光学薄膜破坏的热力过程.研究发现薄膜发生初始破坏所需时间很短,脉冲的大部分时间是引起薄膜发生更大的破坏.在考虑吸收杂质发生相变的情况下,计算了吸收杂质汽化对薄膜产生的蒸汽压力,论证了薄膜发生宏观破坏的可能性.此模型能很好地解释光学薄膜的平底坑破坏形貌.     

水溶液中DNA紫外辐射损伤的分子机制研究

以激光喇曼光谱分析技术,对不同紫外辐射时间条件下ＤＮＡ在水溶液中产生的损伤状况进行研究,结果表明,体外条件下单纯ＤＮＡ水溶液中由紫外辐射直接造成Ｃ→Ｔ的可能性（具体反映在Ｃ→Ｕ这一过程中）是不存在的。胞嘧啶有Ｃ４原子处氨基减少可能,但并无假设衍生形成的尿嘧啶的Ｃ４Ｏ增色表现,不支持胞嘧啶脱氨基直接转变为酮式（成为尿嘧啶）的模型。胞嘧喧Ｎ４Ｈ变形振动的减色似可能证明胞嘧啶的亚氨基化,６１６ｃｍ＾－１