Absolute X-ray yields of light muonic atoms

The intensities of X-rays from muonic atoms formed in low pressure Ne, O₂, N₂, He, and H₂ gas was measured. For the pressure chosen external electron refilling can be neglected. Absolute yields were extracted and compared to results of cascade calculations. Knowledge of the yields of the circular X-ray transitions allows an in situ efficiency calibration of X-ray detectors down to energies of 1.5 keV. This revised version was published online in August 2006 with corrections to the Cover Date.     

软X射线掠射筒状反射镜镀镍磷合金的研究

在软X射线掠射光学系统筒状反射镜的加工过程中,根据对反射镜内表面镍磷合金镀层的质量要求,采用镍盐还原法对筒状微晶玻璃反射镜的内表面进行了活化,并对在含有30g/LNiSO4.6H2O、30g/LNaH2PO2.H2O、25g/LNa(CH3COO).4H2O、18g/LC6H8O7、10mg/L添加剂的镀液中沉积镍磷合金镀层的工艺方法进行了探索。对得到的镍磷合金镀层的结合力、抗腐蚀能力等进行了测试。结果表明,采用此法镀制的镍磷合金镀层结合力达到4B级,耐蚀性好,能够满足光学精密抛光的要求。     

X射线掠入射显微成像诊断技术研究进展

高精密的X射线成像诊断是深入理解内爆过程,揭示点火尺度下未知物理问题的关键。基于掠入射反射的X射线显微镜,结合亚纳米级的超光滑球面或非球面反射镜,能够实现空间分辨优于5 μm的高分辨成像。介绍了国际惯性约束聚变领域的X射线显微成像技术发展及应用,重点展示了我国在高分辨X射线（KB）显微镜、多通道X射线KB显微镜以及大视场X射线KBA显微镜方向的进展,分析了下一阶段超高分辨X射线显微成像的研究计划。通过不断的技术创新,我国的X射线显微成像诊断能力已经达到国际先进水平。     

A study of the electronic excitation of he from grazing incidence ion-surface interaction

The neutralization of He⁺ at grazing incidence from a Ni(111) surface leads to excited states. The light emission from the 3d ³ D and 3d ¹ D states is studied as a function of the beam energy and angular parameters. The observed circular polarization dependence on the crystallographic surface directions is interpreted in terms of the Brillouin zone of the solid.     

Proposal for X-ray spectroscopy of muonic atoms formed from implanted ions in solid hydrogen films

A new method is proposed to extend muonic atom X-ray spectroscopy to the study of nuclear beams, including radioactive beams, by stopping both muon and nuclear beams in a solid hydrogen film. The muon transfer reaction to higher Z nuclei is used then to form muonic atoms. This method would allow studies of the nuclear charge distribution of unstable atoms. This revised version was published online in August 2006 with corrections to the Cover Date.     

Disentangling the K-complex of kaonic hydrogen with DEAR

The DEAR (DAΦNE Exotic Atom Research) experiment at the new φ-factory DAΦNE of Laboratori Nazionali di Frascati aims for a 1% measurement of the line shift of the K-complex due to strong interaction in kaonic hydrogen. This presentation is meant to prove that the high statistics and good resolution obtainable with DEAR will be able to disentangle the kaonic hydrogen K-complex lines (a cascade unconstrained fit), obtaining in this way constraints for what concerns the cascade parameters and, consequently, information regarding the physical processes involved in the kaonic hydrogen atomic cascade. This revised version was published online in August 2006 with corrections to the Cover Date.     

Existence and transition properties of the three-deuteron muonic molecule (3d,2e -,μ-)

We calculated the energy and the size of the three-deuteron muonic molecule (3d,2e ^-,μ^-) = D₃μ. It turns out that this system possesses two equilibrium positions, one at distances typical for muonic molecules, the second one at the usual molecular size. We show, moreover, that the fusion probability of the three deuterons is considerably enhanced due to the existence of a ⁶Li^* threshold resonance. Our estimates indicate that this probability is considerably higher than the decay rate of the competing Auger transition. This revised version was published online in August 2006 with corrections to the Cover Date.     

Ray tracing method for the grazing incidence flat-field imaging soft X-ray spectrometer

A ray tracing method is introduced for helping adjustment and spectra analysis of the grazing incidence flat-field imaging soft X-ray spectrometer. For a single point source, the spectra images obtained by separate components, the toroidal mirror, and the grazing incidence flat-field concave grating with varied line spaces are given respectively. The calculated spectral images of the single point source by the spectrometer are also given for comparison with measurements with different experimental alignments.     

Quantum reflection as the reflection of subwaves

This paper studies quantum reflection with recent research on reflection coefficient. Based on the analytical transfer matrix method, a novel explanation for this phenomenon is proposed that quantum reflection is the reflection of subwaves, which originate inherently from the inhomogeneity of the fields and is always neglected in the semiclassical regime. Comparison with exact formula and the numerical calculations for different potentials has confirmed the reliability and the validity of the proposed theory.     

Mo/Si多层膜小角X射线衍射结构表征

为了实现对Mo/Si多层膜的结构表征,测量了多层膜样品的小角X射线衍射谱。介绍了小角X射线衍射谱的分析方法,包括Bragg峰值拟合法,傅里叶变换法,反射谱拟合法。Bragg峰值拟合法和反射谱拟合法得到多层膜的周期厚度为7.09nm,两种模型的反射谱拟合法得到界面的粗糙度(扩散长度)为0.40～0.41nm(Si在Mo上),0.52～0.70nm(Mo在Si上),前者要比后者小,这与透射电镜法(TEM)得到的结果0.40nm(Si在Mo上),0.6～0.65nm(Mo在Si上)是一致的。通过基于扩散模型的反射谱拟合法得到的折射率剖面也与由高倍率透射电镜(HRTEM)积分得到的灰度值剖面在趋势上是一致的。通过X射线衍射谱和TEM图像对Mo/Si多层膜进行综合表征,得到了多层膜的精细结构信息,这对多层膜制备工艺的优化具有十分重要的意义。     

Nearly backward reflection of bulk acoustic waves at grazing incidence in a TeO2 crystal

Reflection of bulk acoustic waves in a TeO₂ acoustooptic single crystal is studied for the case of a grazing incidence on the free crystal-vacuum boundary. The propagation and reflection of elastic waves is considered in the XOY plane of the material cut out in the form of a rectangular prism. An extraordinary case of reflection at the grazing incidence, when the energy flow of one of the two reflected waves in the crystal is directed opposite to that of the incident wave, is studied. It is shown that the transformation of the incident elastic energy into the energy of the backward-reflected wave can occur with an efficiency close to 100% and can be observed in a wide range of crystal cut angles. An abrupt change of the reflection coefficients in the vicinity of the critical angle is predicted.     

Use of grazing incidence X-ray diffraction for the study of nitrogen implanted stainless steels

The identification of Fe, Ni and Cr nitrides formed by nitrogen-ion implantation (4×10¹⁷ N⁺ cm^-2, 50 keV) in austenitic steels is performed by X-ray diffraction under very low glancing angles (0.00 ⩽ i ⩽ 1.5°). Spectra obtained with increasing angles i permit the investigation of layers with depths varying from 20 to more than 1000 Å. This non-destructive technique allows the surface to be controlled at each step of the treatments. Spectra were recorded on polished steel prior to and after implantation, with or without electrochemical attack. A 100 Å martensitic layer formed during the mechanical polishing is observed on the austenitic substrate. This layer is destroyed by an anodic attack before implantation of the samples. After implantation a CrN or carbonitride overlayer of a few tens of Å in thickness, may be observed. In the subjacent layers several iron and nickel nitrides are present, mainly ϵ-Fe₂N-Fe₃N, ς-Fe₂N and Ni₃N.     

Theory of quasienergetic phenomena in nuclear gamma resonance

An analysis is conducted of the resonance scattering of quanta when a ferromagnet scatterer experiences a single exposure to a strong radiofrequency field which is at resonance with respect to the Zeeman system of nuclear sublevels. The role of the quasienergetic spectrum arising in these conditions (analogous to the effect of a strong field in optics) in the formation of a scattering spectrum and, in particular, the intensity of the additional lines is demonstrated. The relation of the results obtained to those of other workers is discussed.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 111–114, September, 1981.     

氢原子的X射线新谱系的实验观测及其解释

引出氢（氘）气放电产生的射线和粒子流打在非晶聚氘乙烯C2D4和有机玻璃C5H8O2等靶上,测得其散射谱上有多条尖锐的X谱线,其中除一条外都是（不经散射的）原始谱中没有的。经反复证认,这些谱线不是靶中元素（如C或O）和可能包含的杂质元素的特征X射线,也不是原始谱中X射线的衍射线,更不可能是低能电子的轫致辐射经吸收后形成的峰,认为该谱线很可能是前所未知的一类新的原子态的X射线新谱系的一部分。用曾提出的一个“小氢原子”理论模型予以解释,即认为氢（氘）气放电中产生了“小氢原子”,其（在基态）电子轨道半径约为普通氢原子的玻尔半径的1/274,该小氢原子能级之间的跃迁能够很好地解释所测到的X射线新谱系。     

核磁共振陀螺中原子气室温度场的研究

为研究核磁共振陀螺中加热机构对原子气室性能的影响,设计了5种典型加热方式。利用有限元分析软件ANSYS建立了原子气室的温度场模型,给出了原子气室表面的稳态温度场分布情况。同时设计了探测精度为0.01℃的测温电路,对原子气室表面不同位置的温度进行监控,获得了不同加热方式下原子气室表面的温度变化情况。将仿真和实验结果进行比较,发现误差在5%之内,验证了仿真模型的正确性。综合仿真和实验结果比较了不同加热方式下原子气室表面温度分布情况,获得了能够使原子气室表面温度分布最均匀的加热方式。     

Analysis of mesoporous thin films by X-ray reflectivity, optical reflectivity and grazing incidence small angle X-ray scattering

It is well-established that X-ray reflectivity (XR) is an invaluable tool to investigate the structure of thin films. Indeed, this technique provides under correct analysis, the electron density profile of thin films in the direction perpendicular to the substrate. For thin films that exhibit lateral ordering at the nanometer scale, grazing incidence small angle X-ray scattering (GISAXS) ideally complements the XR technique to measure the scattering in off-specular directions. As typical examples, XR and GISAXS data of mesoporous silica thin films and porous materials are presented. The analysis of the XR curve allows to determine the porosity of the film. We also show that the combination of X-ray and visible optical reflection provides information about the index of refraction of thin films. Finally we report how capillary condensation of water can be monitored by XR and GISAXS.