He,Ne,Ar,Kr和Xe原子电子的动量密度分布研究

对He,Ne,Ar,Kr和Xe原子体系中电子在动量空间的性质进行了系统的理论计算研究.采用自洽场HFR方法计算了坐标空间He,Ne,Kr和Xe原子体系单电子径向波函数,动量空间的单电子波函数由坐标空间原子体系单电子径向波函数通过运用傅立叶变换计算得到.在冲量近似条件下,进一步计算研究了这些原子的单电子动量密度分布和原子体系总的Compton轮廓.计算结果与已有的实验实验值和其他文献的理论计算结果比较表明,本文计算的结果是准确的.     

高里德堡态氢原子与氦原子散射的高分辨研究

利用了氢原子飞渡时间谱实验方法对处于高n主量子数里德堡态的氢原子与氦原子的分子束散射过程进行了高分辨研究.测量了H(n)+He→H(n′)+He散射过程的散射微分截面.实验结果表明,产物主要分布在前向散射方向,在侧向也有一定的分布.在前向和侧向存在大量的振荡结构.同时详细的研究也表明,在上述的散射过程中往前散射的方向上,氢原子里德堡态主量子数n的变化并不是很大.实验结果得到了为理论上精确研究高n主量子数里德堡态的氢原子与氦原子的散射动力学的一套精细的实验数据.     

Si离子注入和H等离子体处理对单晶Si中空腔生长的影响研究

室温下首先采用160keVHe离子注入单晶Si样品到剂量5×10¹⁶ions/cm²,部分样品再接受80keVSi离子辐照到较高的剂量5×10¹⁵ions/cm²或接受高密度H等离子体处理.应用透射电镜观测分析了800℃高温退火引起的空腔的形成形貌.结果表明,附加Si离子辐照或H等离子体处理会影响Si中空腔的生长.就Si离子附加辐照而言,由于辐照引入富余的间隙子型缺陷,因此,它会抑制空腔的生长,而高密度H等离子体处理则有助于空腔的生长.定性地讨论了实验结果.     

Xe离子束辐照硼硅酸盐玻璃和石英玻璃效应对比研究

玻璃固化体作为放射性废物地质处置的第一道安全屏障,它的耐辐照性能研究至关重要.玻璃固化体主要网络结构硅氧四面体与石英玻璃的硅氧四面体是一致的,所以这里用石英玻璃代替玻璃固化体作为研究对象.本文采用Xe离子在相同条件下辐照石英玻璃和硼硅酸盐玻璃.利用纳米压痕技术和椭圆偏振仪表征了辐照前后样品的硬度、模量以及折射率的变化情况.结果表明:硼硅酸盐玻璃和石英玻璃的硬度均随着辐照剂量的增大而减小,硼硅酸盐玻璃的模量随着辐照剂量的增大而减小;石英玻璃的模量随着辐照剂量的增大而增大.模量的变化可能和密度的变化有关,这点与折射率的结果相符.     

γ射线辐照对a-SiC:H薄膜结构与特性的影响

 采用射频（13.56 MHz）反应溅射方法制备a-SiC:H 薄膜，并将其在空气中进行高能γ射线(平均为1.25 MeV)辐照，5个样品的吸收剂量分别为0，2×10⁴，4×10⁴，6×10⁴，8×10⁴ Gy。采用拉曼及红外光谱对薄膜的结构进行表征,得到了其结构与特性的变化规律。研究与分析表明：随样品吸收剂量的增加，陷入空穴中的电子会被激发，a-SiC:H薄膜中的SiC成份增加，电阻率变小，数量级为105Ω·cm；薄膜存在结晶化的趋势,其主要原因在于由Si－O－Si键断裂而产生的Si取代膜中C－C键中的C而形成晶态SiC，在此过程中出现了Si－O－Si键及a-SiC:H的减少，晶态SiC的增加。经γ射线辐照后薄膜的氢含量降低，折射率从5.19增大到5.53，辐照后薄膜的透过率均低于原膜的透过率。在500~2 300 cm^-1(对应波长为20.00~5.29 μm)波段内，a-SiC:H薄膜存在一定的增透作用。     

Effects of Kr and Xe ion irradiation on the structure of Y2O3 nanoprecipitates in YBCO thin film conductors

ABSTRACT

The response of Y₂O₃ nanoprecipitates in a 1-µm YBa₂Cu₃O_7-x layer from a superconducting wire Ag/YBCO/buffer metal oxides/Hastelloy to 107?MeV Kr and 167?MeV Xe ion irradiation was investigated using a combination of transmission electron microscopy, diffraction and X-ray energy-dispersive spectrometry. The direct observation of the radiation-induced tracks in Y₂O₃ nanocrystals is reported for the first time to the authors’ best knowledge. Structureless damaged regions of 5–9?nm (average 8?nm) in diameter were observed in Y₂O₃ nanocrystals when the electronic stopping power S_e was about or higher than 4.7 keV/nm. This value of S_e is the upper estimate of the minimum electronic stopping power to create damage in yttria nanocrystals. The electron diffraction patterns, high-resolution transmission electron microscopy, high-resolution scanning transmission electron microscopy, Fourier transform patterns from areas extending a few nanometres around the tracks show that yttria and YBCO keep their respective cubic and orthorhombic pristine structures.     

单晶YSZ的Xe+辐照损伤的电子显微分析

 不同注量200keV Xe⁺ 注入YSZ单晶样品的电子显微分析结果表明，随着辐照注量的增加，缺陷簇的密度增大，在1×10¹⁵~1×10¹⁶cm^-2Xe⁺注量，缺陷簇密度迅速增大，形成间隙型位错环；当Xe⁺注量增大到1×10¹⁷cm^-2，缺陷簇密度的增加变得缓慢，并且有直径为2～4nm的Xe气泡析出。选区电子衍射花样表明YSZ样品没有产生非晶化转变。在Xe⁺辐照的离位率高达约350dpa的情况下，YSZ晶体没有非晶化，其原因主要是由于注入的Xe⁺以气泡形式析出。     

The effects of fast neutron irradiation on oxygen in Czochralski silicon

The effects of fast neutron irradiation on oxygen atoms in Czochralski silicon (CZ-Si) are investigated systemically by using Fourier transform infrared (FTIR) spectrometer and positron annihilation technique (PAT). Through isochronal annealing, it is found that the trend of variation in interstitial oxygen concentration ([O_i]) in fast neutrons irradiated CZ-Si fluctuates largely with temperature increasing, especially between 500 and 700℃. After the CZ-Si is annealed at 600℃, the V₄ appearing as three-dimensional vacancy clusters causes the formation of the molecule-like oxygen clusters, and more importantly these dimers with small binding energies (0.1--1.0eV) can diffuse into the Si lattices more easily than single oxygen atoms, thereby leading to the strong oxygen agglomerations. When the CZ-Si is annealed at temperature increasing up to 700℃, three-dimensional vacancy clusters disappear and the oxygen agglomerations decompose into single oxygen atoms (O) at interstitial sites. Results from FTIR spectrometer and PAT provide an insight into the nature of the [O_i] at temperatures between 500 and 700℃. It turns out that the large fluctuation of [O_i] after short-time annealing from 500 to 700℃ results from the transformation of fast neutron irradiation defects.     

H+辐照前后W涂层表面的XPS分析

对离子束混合技术在不锈钢基体上沉积的W膜进行了H+辐照前后的XPS分析,研究了H+辐照对W的结合能的影响.分析结果表明,沉积的W膜中除了单质钨外,还有部分钨的氧化物,H+辐照结果表明,H+的辐照使钨的结合能向低能方向偏移;钨的氧化物有所减少,说明污染的氧化物在一定程度上被择优溅射掉.     

Pressure effects of He and Xe on the resonance line of strontium

The effects of He pressure (up to a relative density or r.d. of 60) and those of Xe pressure (up to r.d. 13) on the shape of the Sr 4607 or Sr(1) line are reported. The half-width and shift in low foreign gas density region (less than 10 atm) are found to be reasonably linear with He. The linear region for Sr(1)/Xe is highly limited. In He, the line contours are quite symmetrical but in Xe the line contours show very strong red asymmetry. Assuming a Lenard-Jones (6–12) form for the interactomic potentials, the depths of the difference potential well were found via the classical impact theory. These values are 0.86 cm^?1 for Sr(1)/He at an interatomic distance of 7.35 Å and 2.51 cm^?1 for Sr(1)/Xe at 12.83 Å.     

氪灯发光总功率和氙灯发光总能量检测设备

根据氪灯、氙灯发光的工作原理,介绍了氪灯发光总功率和氙灯发光总能量检测系统。该系统可以对氪灯发光总功率和氙灯发光总能量进行批量检验,使用户能在相关激光产品的生产和装配过程中对其进行质量控制,从而提高了激光产品的合格率,缩短了生产时间。在连续氪灯和脉冲氙灯的入厂检验中,氪灯发光总功率和氙灯发光总能量是需要检测的主要技术指标。新型氪灯、氙灯性能综合检测系统是通过采用积分球、功率计以及能量计来检测氪灯的发光总功率和氙灯的发光总能量的。设备由:积分球、功率计、能量计、氪灯和氙灯支架及冷却系统、氪灯和氙灯电源等五部分组成。     

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。     

H2O和HLi分子的双光子激发

用全相对论量子力学计算H2O和HLi的双光子偶极激发。为对比起见,同时用非相对论的对称匹配团族-组态相互作用法(SAC-CI)计算其单光子激发。对于无对称中心的H2O和HLi,符合相应群的对称选择原则。双光子跃迁几率一般比单光子跃迁的小3～5个数量级。在计算双光子偶极激发时,应采用同时包含了空间的对称性和时间反转对称性的全相对论。     

Fine structure effects and phase transition of Xe nanocrystals in Si

We report on an X-ray diffraction study performed on Xe agglomerates obtained by ion implantation in a Si matrix. At low temperature, Xe nano-crystals were formed in Si with different average sizes according to the preparation procedure. High resolution diffraction spectra were detected as a function of the temperature, in the range 15–300 K, showing evidence of fine structure effects in the growth mode of the Xe nanocrystals. We report the first experimental observation of fcc crystalline agglomerates with a lattice parameter expanded by the epitaxial condensation on the Si cavities, whereas for small agglomerates randomly oriented evidence of a contracted lattice was found. For these nanocrystals, a solid-to-liquid transition temperature, size dependent, was detected; above the transition temperature, a fluid phase was observed. Neither overpressurized clusters were detected at any temperature, nor preferential binary size distribution as reported for a metal matrix.     

(e, 3e) Differential cross section of He (21 S) and He (23 S)

The angular distribution of the five-fold differential cross section for the electron impact double ionization of He (2¹ S) and He (2³ S) has been studied. The kinematical conditions for maxima/minima in the angular distribution for the two cases have been compared. The two-step process for the double ionization is found to contribute very little in the triplet case.     

沟道宽长比对深亚微米NMOSFET总剂量辐射与热载流子损伤的影响

本文对不同沟道宽长比的NMOSFET进行了辐射与热载流子应力的试验研究,电参数测量数据表明: 虽然两种损伤的原理具有相似之处,但总剂量辐射与热载流子的损伤表现形式及对沟道宽长比的依赖关系均不同.辐射损伤的最大特点是关态泄漏电流增加,并且损伤与沟道宽长比成反比;热载流子损伤会造成跨导等参数的显著变化,但关态泄漏电流无明显改变,并且损伤随沟道长度与宽度的减小而增大.从二者基本原理出发,结合宏观参数的表现形式,文中对辐射与热载流子损伤进行了详细分析,认为造成二者损伤差异及对沟道宽长比不同依赖关系的原因在于辐射与热载子注入引入的陷阱电荷部位不同.因此对两种损伤进行加固时应重点从器件设计尺寸、结构等方面综合考虑.     

He／K系统两步激励产生极紫外相干辐射机制中的斯托克斯及反斯托克斯竞争过程

讨论了Ｈｅ／Ｋ混合蒸汽中两步激励产生极紫外（ＸＵＶ）相干辐射机制中存在的斯托克斯及反斯托克斯跃迁过程．计算了有关跃迁的振子强度、极紫外辐射过程及其竞争过程的受激拉曼散射增益系数和阈值．结果表明，其中６４．３ｎｍ极紫外相干辐射的产生过程与其竞争过程相比，具有最大的增益及最小的阈值；但到能级Ｋ［３ｐ５４ｓ２２Ｐ１／２，３／２］的反斯托克斯跃迁及到能级Ｋ［３ｐ５３ｄ（３Ｐ）４ｓ２２Ｐ１／２，３／２］的斯托克斯跃迁将对其中５９．８ｎｍ极紫外相干辐射的产生构成严重竞争．     

Roles of local He concentration and Si sample orientation on cavity growth in amorphous silicon

(111)- and (100)-oriented Si samples were implanted with Si⁺ ions at 1 MeV to a dose of 1?×?10¹⁶?cm^?2 and with 5?×?10¹⁶ He⁺ cm^?2 at 10?keV or 50?keV and eventually annealed in the 800–1000°C temperature range. Sample characterisation was carried out by cross-section transmission electron microscopy, positron annihilation spectroscopy and nuclear reaction analysis. In addition to the formation of He bubbles at the projected range of He, bubbles were observed after solid-phase epitaxial growth (SPEG) of the embedded amorphous Si layer. The He threshold concentration required to obtain thermally stable bubbles in amorphised Si is between one and four orders of magnitude lower than in c-Si. Since bubble formation and growth take place in the a-Si phase, the interaction with SPEG during annealing was studied by considering (100) and (111) Si. Both the SPEG velocity and the resulting defects play a role on bubble spatial distribution and size, resulting in bigger bubbles in (111) Si with respect to (100) Si.     

氪灯和氙灯光谱强度分布和光谱效率测量

氪灯、氙灯光谱强度分布和光谱效率测量是反映氪灯、氙灯性能的关键指标。介绍了一套新型的氪灯、氙灯光谱强度分布和光谱效率检测系统。该系统是一套测量连续发光灯和脉冲闪光灯发光性能及效果的综合检测设备。该检测单元采用计算机进行操控,人机界面良好,便于检验人员进行氪灯和氙灯光谱强度分布和光谱效率的批量检测。检验人员利用该系统可进行装机模拟试验和可靠性试验,可对氪灯和氙灯的性能进行必要的分析研究,不断地积累了氪灯和氙灯的检验数据和经验。     

The study of damage and optical properties in LiNbO3 implanted by MeV Er and He ions

Abstract

Two LiNbO₃ (X and Y cut) crystals from different companies were implanted by 3.0 MeV Er ions to a dose of 7.5 × 10¹⁴ ions/cm² and 3.5 × 10¹⁴ ions/cm² with different beam current densities, respectively. After annealing at 1060°C in air for 2 hours, one LiNbO₃ sample was implanted by 1.5 MeV He ions to a dose of 1.5 × 10¹⁶ ions/cm². The Rutherford backscattering/channeling and prism coupling method have been used to study the damage and optical properties in implanted LiNbO₃. The results show: (1) the damage in LiNbO₃ created by 3.0 MeV Er ions depends strongly on the beam current density; (2) after annealing at 1060°C in air for 2 hours, a good Er doped LiNbO₃ crystal was obtained; (3) there is waveguide formation possible in this Er-doped annealed LiNbO₃ after 1.5 MeV He ion implantation. It is suggested that annealing is needed to remove the damage created by MeV Er ions before the MeV He ion implantation takes place, to realize the waveguide laser for Er doped LiNbO₃.