共查询到20条相似文献,搜索用时 140 毫秒
1.
2.
利用中国原子能科学研究院HI-13MV串列加速器上提供的动能为15—55 MeV的类氦C离子分别轰击Fe, Ni, Nb和Mo金属厚靶,采用HpGe探测器测量了K-X射线,获得了相应的K-X射线的发射截面.本文中由于各个靶原子外壳层电离度的不同,类氦C离子与Fe, Ni靶原子相互作用发射的Kβ与Kα X射线的分支强度比随入射离子动能增加而减小,而Nb, Mo靶原子发射的K-X射线分支强度比变化不明显.利用厚靶截面公式计算了靶原子K-X射线的发射截面,并与不同的理论模型及质子的结果进行了对比.结果表明随类氦C离子动能的增大, Fe, Ni靶原子发射的Kβ与Kα X射线的总产生截面与考虑多电离的两体碰撞近似修正模型最为符合Nb, Mo靶原子发射的Kβ与Kα X射线的总产生截面与平面波恩近似模型的理论值最为接近.质子与单核子C离子能量相同时,质子比类氦C离子激发不同靶的K-X射线产生截面约小3个数量级. 相似文献
3.
4.
受温度及密度等环境效应影响,温稠密物质的电子结构发生显著变化,其理论描述非常复杂,精密实验测量亦极其困难.本文发展了基于X射线荧光光谱研究温稠密物质离化分布的实验方法,结合理论研究有助于深入理解温稠密物质的电子结构变化.在万焦耳激光装置上,设计特殊构型黑腔复合加载产生数十eV、近固体密度的稠密Ti物质,利用激光辐照V产生的热发射线泵浦Ti的荧光,并采用晶体谱仪诊断样品的X射线荧光光谱.实验中获得冷样品和加载样品的荧光光谱,观测到加载样品Kα及Kβ荧光谱线相对于冷样品光谱在高能侧的显著变化,结合理论计算解释了加载样品荧光谱线的变化主要来源于其温度上升后离化分布的改变,建立了基于X射线荧光光谱的温稠密物质离化分布实验研究能力. 相似文献
5.
6.
7.
8.
测量了动能为2.0–6.0 MeV的高电荷态离子152Eu20+ 入射Au表面产生的特征X射线谱, 结果表明, 相互作用不仅激发出了Au的 Mζ, Mα和Mδ特征X射线, 还激发出了Eu的Mα X射线, 且X射线总产额随入射离子动能的增加而增加. 计算了Au的M壳层总的X射线产生截面, 并与理论模型的计算结果做了比较分析.
关键词:
高电荷态离子
X射线
产额
截面 相似文献
9.
根据质量劈裂公式计算了轴矢介子多重态(11P1)中底偶素的质量,然后利用粒子表上最新的实验数据,在雷吉唯象的框架下计算轴矢介子多重态中双重介子Bc1、奇异偶素(ss-bar和奇异介子K1B的质量. 最后在介子-介子混合的框架下,计算了K1A - K1B混合角和轴矢介子九重态中两个同位旋标量态的混合角. 我们建议实验上在1478 MeV能量附近进一步研究轴矢介子h1(1380)的性质,在6774 MeV能量附近寻找和研究轴矢介子Bc1(1P).本文的计算结果对于实验上寻找还没有观测到的双重介子态Bc1以及理解K1A - K1B混合和轴矢介子九重态的混合有一定的意义.
关键词:
介子谱
雷吉轨迹
介子-介子混合 相似文献
10.
用位置空间的重整化群方法,讨论W(112)p(2×1)-O化学吸附系统的有序-无序相变。采用周期性集团的递推关系,进行了将格点组成单胞,再将单胞组成周期性集团的4×4重整化变换,考虑最近邻、次近邻氧原子之间的对相互作用以及三个氧原子之间和四个氧原子之间的相互作用,求出重整化群耦合参数K′α和格点间相互作用参数Kα之间的关系,确定了固定点Kα*求出不同覆盖度下的临界温度Tc,得到与实验结果相符合的W(112)p(2×1)-O相图。
关键词: 相似文献
11.
Robert F. Reilman Alfred Msezane Steven T. Manson 《Journal of Electron Spectroscopy and Related Phenomena》1976,8(5):389-394
The relative intensities of photoelectron lines is discussed. The relationship of observed intensities to angle of observation is considered as are the errors introduced by ignoring the fact that different lines may have different angular distributions. Tables of theoretical results for the angular distribution asymmetry parameter, β, are presented for incident Al Kα, Mg Kα, and Zr Mζ radiation for all atomic ground state subshells of non-zero angular momentum. The application of these results to molecules is discussed. 相似文献
12.
Erdogan Büyükkasap 《应用光谱学评论》2013,48(1-2):151-158
INTRODUCTION Knowing the Kβ/Kα intensity ratio is of great practical importance in the analysis of X-ray spectra. The information is needed in the experimental investigations of various phenomena in the fields of atomic, nuclear and radiation physics and non-destructive testing of materials and elemental analysis using X-ray fluorescence techniques. Kα, X-ray arise from transition from the L shell to K shell and Kβ, X-ray arise from transition from the M, N, 0 shells to K shell. 相似文献
13.
C.P. Bhalla 《Physics letters. A》1973,45(1):19-20
Theoretical calculations of ωK, changes in the Kα and Kβ X-ray energies and ratios of Kβ and Kα intensities for multiply-ionized argon are presented using the nonrelativistic Hartree-Fock-Slater atomic model. 相似文献
14.
Nuray Kup Aylikci 《光谱学快报》2013,46(6):346-355
AbstractIn this study, Kα1,2, Kβ1,3, and Kβ2,4 X-ray natural line widths for various elements were determined semi-empirically at 123.6?keV by using K shell fluorescence yields obtained from energy dispersive X-ray fluorescence measurements. The obtained results contribute to a database for the development of new theoretical models of atomic structure, radiation shielding materials, and designing new technological devices related to the structural analysis of materials. The obtained results were compared with the literature, while new fitting polynomials for the studied parameters were acquired. The results showed that the natural linewidths of K X-ray lines fit fourth-order polynomials except for Kβ2,4. 相似文献
15.
M. B. Agranat N. E. Andreev S. I. Ashitkov A. V. Ovchinnikov D. S. Sitnikov V. E. Fortov A. P. Shevel’ko 《JETP Letters》2006,83(2):72-74
Characteristic K α x rays arising when a metallic target is irradiated by femtosecond infrared pulses that are generated by a terawatt chromium-forsterite laser system (1240 nm, 90 mJ, 80 fs) are studied. The absolute yield (up to 3 × 108 photons/sr pulse) and the coefficient of the transformation of laser radiation to K α radiation (maximum value ≈0.03%) are measured for an iron target. The dependence of the radiation intensity on the angle of incidence of p polarized laser radiation is analyzed. The mechanisms of the production of fast electrons responsible for generating characteristic x rays are discussed. 相似文献
16.
K-shell X-ray production cross sections for oxygen ions on thin solid targets of 13 selected elements with atomic numbers between 16 and 35 were measured by a Si(Li) detector at incident ion energies from 7 to 24 MeV. Ionization cross sections are compared with calculations assuming Coulomb-ionization. Best agreement is found with theoretical cross sections that include corrections for binding energy and Coulomb deflection effects. Energy shifts ofK α andK β X-rays andK α /K β intensity ratios were also measured and are used to deduce information about outer shell ionization. 相似文献
17.
The production of target atomK-shell X-rays has been studied for 2 to 28 MeV fluorine ions incident on thin solid targets of 14 elements with atomic numbers Z2=22 to 57. Total X-ray production cross sections, energy shifts ofK α andK β lines andK α/K β intensity ratios were measured with a Si(Li) detector. The results of cross section measurements are compared with theoretical predictions of inner shell ionization. In most cases, satisfactory agreement between measured cross sections and theoretical Coulomb ionization cross sections, corrected for the perturbation of the target atom by the projectile charge and for relativistic effects, was obtained. 相似文献
18.
We investigate the effect of the hexadecapole (K=4) polarization moment on the spatial distributions of angular momenta for atoms produced during the photodissociation of diatomic or triatomic molecules by polarized radiation. We derive general expressions for the angular distributions of the atomic density matrix for K = 2, 4 and expressions for the corresponding anisotropy parameters that contain all information on the photodissociation dynamics. We show that these anisotropy parameters can be experimentally determined by using ion imaging. We consider oxygen atoms in the 1 D 2 state aligned with respect to the orbital angular momentum as an example and provide ion images of the signals that correspond to the population of the atomic magnetic sublevels ¦m¦ = 0, 1, 2. We show the contributions from the second-and fourth-rank state multipoles to the angular distributions of the atomic density matrix to be comparable in magnitude and significantly different in form. 相似文献
19.
Ragnar Nordberg Kjell Hamrin Anders Fahlman Carl Nordling Kai Siegbahn 《Zeitschrift für Physik A Hadrons and Nuclei》1966,192(5):462-475
Energies of atomic electrons in theK andL shells of eighteen elements of low atomic numbers have been measured by electron spectroscopy. Tabulated values for theL I energies are shown to be in need of considerable revision. AluminumKα radiation is shown to have high potentialities for ESCA studies. 相似文献
20.
The relative intensity of Kα/Kβ for cobalt in thick targets with cobalt mass densities from 0.51 to 22.49% has been measured by the wavelength dispersive x‐ray fluorescence (XRF) spectrometer. The measuring conditions are: tube current ranging from 10 to 60 mA and voltages ranging from 20 to 60 kV. We plotted the Kα/Kβ ratio vs Co densities for different tube voltages and currents. Our study shows that the Kα/Kβ ratio is below the theoretical value for low Co densities and it increases with increasing Co density. For higher x‐ray energies, the Kα/Kβ ratio shows a sharp growth at the special density and then reaches a nearly constant value. However, Kα/Kβ ratio is theoretically constant and independent of energy in thin target measurements. The changes of this ratio according to the x‐ray energy and the element density have been studied in thick target measurements. The results provide experimental evidence to suggest that exciting energy and element density can indeed affect the Kα/Kβ ratio. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献