分子束外延GaN薄膜的X射线光电子能谱和俄歇电子能谱研究

用XPS和AES电子能谱的方法对等离子体辅助分子束外延(MBE)生长的GaN薄膜进行了表面分析和深度剖析.发现红外分子束外延(RFMBE)生长的富镓GaN薄膜实际表面存在O和C吸附层,C主要为物理吸附,而O在GaN表面形成局域化学键产生氧络合物覆盖层,并形成一定的深度分布.杂质O在GaN带隙中导带底形成杂质带同时引入深受主能级,使得带隙变窄室温光吸收谱向低能方向移动,光致发光谱出现宽带发光峰.从而影响GaN薄膜的电学和光学性质 关键词： GaN薄膜 X射线光电子能谱 俄歇电子能谱 表面分析     

X射线光电子能谱中的俄歇参数

简要介绍了几种俄歇参数定义以及俄歇参数图中涉及的原子外部驰豫能和俄歇双电离体系终态能，最后评述它们的应用。     

MBE生长氮化镓薄膜的X光电子谱和俄歇电子谱分析

用X光电子谱和俄歇电子能谱的方法对射频等离子体辅助分子束外延(MBE)技术生长的氮化镓(GaN)薄膜进行了表面分析和深度剖析.发现薄膜实际表面存在O和C吸附层,C主要为表面污染,而O形成一定的深度分布,从而影响氮化镓薄膜的电学和光学性质.     

同核异能跃迁衰变的γ射线强度计算

简要介绍了同核异能跃迁衰变的γ射线强度的计算方法,并以实例进行说明,还给出了有关的物理自洽检验方法及其讨论.     

X射线光电发射材料

分析Ｘ射线光电效应的特点,讨论俄歇电子和二次发射电子的产生机理。从“自由原子”模型出发,在理论上探讨Ｘ射线光电发射的原理,建立Ｘ射线光电发射的初步理论模型,讨论影响Ｘ躬一光电发射量子产额的几个特性参数,并对两上国际上常用的绝缘材料进行了计算,在此基础上提出了具有较高量子产额的全新硬Ｘ射线光电阴极模型。     

用于软X射线激光实验的铝衰减膜的测量

对不同方法制备的不同厚度的铝衰减膜,用微机控制α测厚仪测量了膜的质量厚度以及膜厚均匀性,用Auser电子能谱(AES)对铝膜进行了组分的表面和深度分布分析,根据铝KLL Auger特征谱揭示了氧化膜的化学组分并测量了氧化膜厚度随放置时间的变化,还讨论了膜中其它杂质含量的上限。     

超高真空俄歇电子能谱原位加热和GaN热效应研究

建立一套基于超高真空俄歇电子能谱的原位加热系统,对GaN薄膜进行热效应研究．随着温度的增加,Ga LMM和Ga MVV的动能减小．利用第一性原理计算,获得理论的GaMVV俄歇谱.加热过程由于晶格热膨胀以及表面原子再构引起价电子态密度发生变化,从而导致价带俄歇谱负移．     

核结构和衰变数据评价国际协作网活动

简要介绍了核结构和衰变数据评价国际协作网的组建，中国小组评价活动，历届会议简况，以及第１１届会议取得的主要成果。     

α衰变的γ射线强度计算

简要介绍了α衰变的γ射线强度的计算方法,并以实例进行说明,还给出了有关强度平衡的物理自洽检验方法及其讨论.     

175Hf核ε衰变的IXK/Iγ(343keV)比值计算和分析及其辐射数据计算

简要地介绍了¹⁷⁵Hf核ε衰变的I_XK/I_γ(343keV)比值的计算方法与实验测量的比较与分析,并在此基础上,计算得到了P_γ(343keV)=0.869±0.004,还给出了¹⁷⁵Hf核ε衰变的辐射数据的计算与推荐     

活化反应截面评价中核衰变数据的作用和影响

就核衰变数据在活化反应截面评价中的作用和影响作了比较详细的介绍,通过几个实例,说明在活化反应截面评价中必须充分考虑核衰变数据的作用和影响.核衰变数据的不准确性有时是造成活化反应截面彼此间分歧的主要原因.     

PCA-Based Analysis of X-Ray-Excited Auger Spectra from Non-ordered Ag(110)

Principal-components analysis (PCA) followed by factor analysis enables one to decompose the structure of Auger lines originating from large effects such as energy shifts induced by chemical effects. The aim of the present contribution is to show that PCA can also be effectively used for detection of composed structure in a set of Auger spectra even if the observed changes in line shape are very subtle. The analysed set of X-ray-excited MNN Auger spectra from Ag(110) shows a clear correlation between peak shifts and peak widths. This correlation can be explained as a result of the composed structure of the recorded Auger lines. It is suggested that the resultant Auger lines may consist of a number of constituents, each referred to Ag atoms differing in the value of their co-ordination number.     

ε衰变的能量和强度平衡计算

文中给出了ε衰变的能量和强度平衡的计算公式,并以⁵²Mn的ε衰变为例说明其实际应用.     

产生医用放射性核素核数据的测量、 理论计算与评价(续)

简要介绍产生治疗放射性核素 (利用反应堆、 加速器或衰变而产生的26个核素、 61种不同反应途径) 核数据的测量、 理论计算与评价的新进展。 这些核素是: 已广泛用于临床的32P, 89Sr, 90Y, 103Pd,125I,131I, 137Cs, 153Sm,186Re,188Re,192Ir和具有很大潜在使用可能性的64Cu,67Cu,67Ga, 86Y, 105Rh,111In,114mIn,124I, 125I(新),149Pm, 166Ho,169Yb,177Lu,211At,213Bi,225Ac。 61种不同反应途径中有6种新的反应途径。 为提高核医学应用的安全性和有效性, 对现有核数据进行评价与适当能区的理论计算是十分必要的。 The nuclear data measurements and preliminary evaluation as well as theoretical calculation for established and emerging 26 radio nuclides produced in 61 ways by using reactor, accelerator or decay are briefly introduced. The measured data evaluation and theoretical calculation in some energy range are very important in order to keep the safety and validity in medical therapeutic applications. The 11 established radio nuclides are 32P, 89Sr, 90Y, 103Pd,125I,131I, 137Cs, 153Sm,186Re,188Re,192Ir and the 16 emerging radio nuclides are 64Cu,67Cu,67Ga, 86Y, 105Rh,111In,114mIn,124I, 125I(new),149Pm, 166Ho,169Yb,177Lu,211At,213Bi,225Ac.     

The KLL Auger spectrum of neon from the EC-decay of Na

The low energy KLL Auger electrons of neon emitted after EC-decay of ²²Na have been investigated with a 4 eV instrumental resolution using an electrostatic spectrometer and a solid state radioactive source. This is the first experimental investigation of the KLL Auger spectrum of neon from the solid state. Relative intensities and energies of all resolved spectrum components were determined. Measured absolute energy of the dominant KL₂L₃(¹D) transition was found to be 824.5(19) eV, i.e. about 20 eV higher than that obtained in experiments with free Ne atoms. Within the experimental uncertainties, no influence of solid state effects on relative intensities of the KLL transitions was found.     

Decay energy of 55Fe from its inner bremsstrahlung spectrum

Several measurements of decay energy using the inner Bremsstrahlung spectrum (IB) due to radiative electron capture in ⁵⁵Fe has been made. But the results are not uniform. Hence another attempt has been made at the same. Experimental data was obtained with a 4.445 cm. dia × 5.08 cm thick Nal (Tl) detector. It was subjected to suitable statistical treatment and various corrections using Liden and Starfelt procedure. The corrected spectrum agrees well with the Glauber and Martin theory for 1s electron capture beyond 100 keV. From the Jauch plot, the decay energy of 232.36±0.64 keV was obtained.     

Nuclear Uptake of Gold Nanoparticles Deduced Using Dual‐Angle X‐Ray Fluorescence Mapping

Studies into the cell nucleus' incorporation of gold nanoparticles (AuNPs) are often limited by ambiguities arising from conventional imaging techniques. Indeed, it is suggested that to date there is no unambiguous imaging evidence for such uptake in whole cells, particularly at the single nanoparticle level. This shortcoming in understanding exists despite the nucleus being the most important subcellular compartment in eukaryotes and gold being the most commonly used metal nanoparticle in medical applications. Here, dual‐angle X‐ray flouresence is used to show individually resolved nanoparticles within the cell nucleus, finding them to be well separated and 79% of the intranuclear population to be monodispersed. These findings have important implications for nanomedicine, illustrated here through a specific exemplar of the predicted enhancement of radiation effects arising from the observed AuNPs, finding intranuclear dose enhancements spanning nearly five orders of magnitude.     

p+209Bi核反应微观数据的理论计算

利用光学模型、激光模型、蒸发模型及扭曲波玻恩近似理论,对入射能量从阈能到300MeV,p+²⁰⁹Bi的中子反应截面、剩余核截面、出射粒子的多重数进行了理论计算及分析,并将计算结果与实验数据进行了比较.同时得到一组能量到50?0MeV与实验数据符合很好的光学势参数.