共查询到20条相似文献,搜索用时 22 毫秒
1.
根据同步辐射光源对软X射线分光晶体的性能要求,分析了软X射线能区常用分光晶体的性能优劣,指出对于晶格常数值大的分光晶体,KTP(KTiOPO4)(011)是该能区比较理想的分光晶体. 同时提出了一种利用同步辐射光源测量晶体衍射效率的实验方法,指出光源的发散度与晶体的衍射效率密切相关. 测量了KTP(011)晶体的晶格常数,给出了KTP(011)晶体的实测衍射效率.
关键词:
同步辐射
KTP(011)晶体
衍射效率
光源发散度 相似文献
2.
3.
本文叙述邻苯二甲酸氢钾(KAP)晶体内部不完整性(滑移位错等)的同步辐射截面形貌图的衬度研究工作。有关缺陷象衬度随波长增加而提高的实验事实同引用均匀畸变动力学的理论所引入的平均应变梯度参数β和βteff的理论计算结果,相当符合,它为应用同步辐射源来清晰显示单晶中有关缺陷,提供一个波长选择的依据。
关键词: 相似文献
4.
Efficiency calibrations of cylindrically bent transmission crystals in the 20 to 80 keV x-ray energy range 总被引:1,自引:0,他引:1
Szabo CI Feldman U Seltzer S Hudson LT O'Brien M Park HS Seely JF 《Optics letters》2011,36(8):1335-1337
Two quartz (10-11) crystals were cylindrically bent to a 25.4 cm radius of curvature and were mounted in identical Cauchois-type transmission spectrometers, and the crystal diffraction efficiencies were measured to 5% absolute accuracy using narrow bandwidth x-ray source fluences in the 20 to 80 keV energy range. The measured integrated reflectivity values were compared to calculations performed using a computational model that accounts for the diffraction geometry of the bent transmission crystal. These crystal calibrations enable the accurate measurement of absolute hard x-ray emission levels from laser-produced plasmas and other laboratory sources. 相似文献
5.
P. Schattschneider A. Wagendristel 《Applied Physics A: Materials Science & Processing》1983,31(2):81-86
A method for the retrieval of concentration spectra of crystalline mixtures from x-ray diffraction profiles is described. Both spectra are associated with an integral equation which can be simplified to yield a set of linear equations. Solutions are readily obtained by triangular decomposition since the equations are typically described by band matrices. The method has been tested with simulated diffraction profiles to allow for a variety of options concerning the concentration spectra. The procedure is well suited for binary alloys containing crystals of different structure and lattice parameters. The time consumption of the calculations is significantly reduced as compared to hitherto available methods. 相似文献
6.
M. K. Balyan 《Journal of Contemporary Physics (Armenian Academy of Sciences)》2016,51(4):391-397
Diffraction of a spatially inhomogeneous X-ray wave was theoretically studied in a crystal with cubic nonlinear response to the strength of an external electric field. Using numerical calculations in case of two-beam diffraction of a narrow incident beam, the intensity distributions on the output surface of the crystal was investigated depending on the thickness and intensity of the incident beam. The results of numerical calculations of integral (spatial) coefficients of transmission and reflection are given as functions of incident wave intensity for fixed thickness of the crystal. 相似文献
7.
8.
The semiorganic crystal of sodium acid phthalate (NaAP) single crystals was grown in the solvent of water by slow evaporation method at room temperature. The single crystal X-ray diffraction studies showed the crystal belongs to orthorhombic system. The optical absorption spectrum reveals that the crystal has good transparency in entire visible region. The hardness number of the material is measured by microhardness tester. The fluorescence green colour emission exhibits is semiorganic. The SHG efficiency of NaAP crystal confirms NLO behaviour of green colour emission to provide frequency doubling process for photo electronic applications. 相似文献
9.
以北京同步辐射实验室4B7中能束线为光源,在2.1~6.0 keV的范围内对邻苯二钾酸氢铊(TlAP)平面晶体一、二 、三级衍射的积分衍射效率进行了精确的实验标定。标定结果表明:TlAP晶体有较高的峰值衍射率; 其一级衍射的积分衍射效率向低能端有增加的趋势,而在2.6~5.4 keV的范围内大约为1.53×10-4 rad;随着衍射级次的提高,衍射效率逐渐减小,二级衍射的积分衍射效率约为一级衍射效率的1/4,三级衍射结果比一级衍射下降一个量级。实验所标定的TlAP晶体可用于平晶谱仪对激光等离子体X射线光谱的定量分析。 相似文献
10.
Fine structure of the diffraction image of an edge dislocation in high-resolution section topography
E. V. Suvorov I. A. Smirnova 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2008,2(5):777-782
The propagation of an x-ray wave field in an elastic field of an edge dislocation crossing a scattering triangle exactly along the bisector of the scattering angle has been considered. The scattering of the x-ray wave field by a complex elastic field of the edge dislocation has been analyzed using the methods of geometrical optics. It has been established that the fine structure of a diffraction image of defects in thick crystals is determined by the differences in scattering of the normal and anomalous modes of the x-ray wave field in the vicinity of the Bragg reflection. In the case of thick crystals, the x-ray diffraction image of defects can have a symmetry different from the symmetry of the function of local misorientations of the crystal lattice. X-ray wave scattering by local distortions of the crystal lattice can occur according to two different mechanisms depending on the gradient of space changes in the deformation field. In the crystal regions where the elastic field varies slowly with a change in the distance, the x-ray wave field has had time to adjust itself to follow the course of deviations of the crystal lattice from the exact Bragg condition. In the crystal region where the elastic field changes significantly at distances of the order of the extinction length, this region leaves the reflecting position and interference scattering occurs at the interface of the region. It is important that the form of the deformation field in this case is of no significance. 相似文献
11.
Tanaka Y Takeuchi T Lovesey SW Knight KS Chainani A Takata Y Oura M Senba Y Ohashi H Shin S 《Physical review letters》2008,100(14):145502
Enantiomers, or stereoisomers, have crystal structures that are mirror images of each other and are thus handed, like our right and left hands. The physical properties of enantiomers are identical except for optical activity, which rotates linearly polarized light by equal amounts but in opposite directions. While conventional x-ray Bragg diffraction can determine crystal structures, it does not distinguish between right- and left-handed crystals. We show resonant Bragg diffraction using circularly polarized x rays reveals the handedness of crystals by coupling x-ray helicity to a crystal screw axis. The intensity of resonantly allowed reflection of alpha-quartz is well described by an admixture of a parity-even and a parity-odd process. Our results are of general importance and demonstrate a new method to directly study chiral motifs in structures that include biomaterials, liquid crystals, magnets, multiferroics, etc. 相似文献
12.
Petukhov AV Dolbnya IP Aarts DG Vroege GJ Lekkerkerker HN 《Physical review letters》2003,90(2):028304
Synchrotron small-angle x-ray diffraction images of random-stacking-induced Bragg scattering rods are obtained in a wide range of wave vectors from a single colloidal crystal. The results reveal a strong multiple scattering effect, which leads to new features in the diffraction pattern-secondary Bragg rods. We argue that dynamic x-ray diffraction is rather common for high-quality colloidal photonic crystals and should be taken into account. 相似文献
13.
14.
S. Krishnan 《Journal of Physics and Chemistry of Solids》2008,69(11):2883-2887
Sodium acid phthalate (SAP), an efficient semi-organic crystal having dimensions 17×8×2 mm3 has been grown from aqueous solution by slow evaporation technique at room temperature within the period of 2 weeks. The lattice parameters of the grown crystals were determined using single-crystal X-ray diffraction analysis. The presence of functional groups was estimated qualitatively by Fourier transform infrared (FTIR) analysis. The band gap energy was determined using optical absorption studies. The TG/DTA analysis reveals that the SAP crystal is thermally stable up to 141.6 °C. The dielectric constant and dielectric loss was studied as a function of frequency and the corresponding activation energy (Ea) has been calculated for the grown crystal. Scanning electron microscope studies enunciate the ferroelectric domain patterns of the SAP crystal. Ferroelectric property of the grown crystal was confirmed by hysteresis loop studies. 相似文献
15.
M. Krishna Mohan K. Jagannathan S. Ponnusamy C. Muthamizhchelvan 《Journal of Physics and Chemistry of Solids》2011,72(11):1273-1278
Pure, urea and thiourea doped hippuric acid (HA) single crystals have been grown in acetone using slow evaporation technique at a constant temperature, with the vision to improve the properties of the crystals. The crystal systems and the unit cell parameters of the grown crystals were identified from single crystal X-ray diffraction. The crystalline nature of the grown crystals was confirmed by powder X-ray diffraction and the diffraction peaks were indexed. The variations in composition due to the addition of dopants were identified by CHNS analysis. FT-IR studies reveal the presence of different vibrational bands. The optical characteristics were assessed by UV–vis analysis and it indicates the transmission in the visible region. TGA and DSC studies indicate the thermal behavior of pure and doped crystals. The Second Harmonic Generation (SHG) has been tested using Kurtz Powder Technique for the pure and doped crystals. It is found that the thiourea doped hippuric acid crystals have SHG efficiency of 2.08 times higher than that of potassium dihydrogen phosphate (KDP) single crystal. The dielectric studies were carried out, and the variations of dielectric constant and dielectric loss with temperature have been studied. 相似文献
16.
Back-reflection x-ray diffraction topography is used the measure the real structure of the surface layer of CdTe single crystals.
It is found that the structural changes depend mainly on the laser power, on the presence of a doping impurity, and on the
orientation and profile of the sample surface. Three distinct and conspicuous phenomena are discussed: overall improvement
of the real structure of the surface layer, the periodic relief of the crystal surface, and twin mosaic structure.
Fiz. Tverd. Tela (St. Petersburg) 40, 68–72 (January 1998) 相似文献
17.
In this paper, we performed the synthesis, characterization, and computational studies on Vanillin isoniazid (VIN) single crystals grown by the slow evaporation solution growth technique. The crystalline perfection and monoclinic crystal structure with space group Cc have been confirmed using single-crystal X-ray diffraction and powder X-ray diffraction method. The presence of various functional groups has been identified by FTIR and Raman spectroscopy. These data are in good agreement with theoretical and experimental values of FT-IR, FT-Raman.The optical absorption studies were carried out for the grown crystal VIN which has been analyzed by UV–Vis–NIR spectroscopy. Thermogravimetric (TG) and differential thermal analysis (DTA) were carried out to characterize the thermal stability of the VIN crystals. The quantum chemical calculations for VIN crystal are performed at the B3LYP, B3PW91, levels of theory with the 6–311++G(d,p) basis set. Finally, inter-and intramolecular charge transfer, hyper conjugative interaction of the compound is investigated from natural bond orbital (NBO) analysis. The Mulliken atomic charge of VIN single crystal has been investigated using theoretical calculations. 相似文献
18.
19.
M. Dosiere 《Journal of Macromolecular Science: Physics》2013,52(3-4):303-328
The phase diagrams of the binary systems poly(ethylene oxide) (PEO)-resorcinol and poly(ethylene oxide)-p-nitrophenol show the presence of molecular complexes with well-defined stoichiometries. The crystal structure of these two molecular complexes has been determined from wide-angle x-ray diffraction patterns of stretched films and spherulites. The morphology of the two complexes crystallized from the melt is investigated by differential scanning calorimetry and small-angle x-ray scattering. The crystallization of the PEO-resorcinol complex from the melt gives integral-folded crystals with either extended chains (EC) or n-folded chains (n-FC). As observed for PEO oligomers, the fraction of EC crystals of the PEO-resorcinol complex increases with the crystallization temperature to give finally only EC crystals but in a larger range of crystallization temperatures than for pure PEO. On the other hand, the PEO-p-nitrophenol complex crystallizes over all the studied crystallization range as stable nonintegral-folded (NIF) crystals. Two proposals related to the crystal structure of these complexes and their mode of growth are invoked to explain these two greatly different morphologies at the lamellar level. 相似文献
20.
A. I. Slutsker V. L. Gilyarov G. Dadobaev L. A. Laius I. V. Gofman Yu. I. Polikarpov 《Physics of the Solid State》2002,44(5):964-971
The experimental temperature dependences of the thermal expansion coefficient and the mean-square amplitude of atomic vibrations in the longitudinal direction (along the axes of chain molecules) in poly(ethylene) crystals of different sizes are measured using x-ray diffraction in the temperature range 5–350 K. Theoretical calculations of the temperature dependences of the thermal expansion coefficient and the mean-square amplitude of atomic vibrations in poly(ethylene) crystals are carried out. It is shown that the results of calculations are in good agreement with experimental data. The temperature ranges in which the quantum character of lattice dynamics affects the thermal expansion coefficient and the mean-square amplitude of vibrations are determined. It is revealed that the shear longitudinal modes play an important role in the lattice dynamics of crystals with a chain structure. 相似文献