Tianxi Sun

Application of confocal X-ray fluorescence micro-spectroscopy to the investigation of paint layers

A confocal micro X-ray fluorescence (MXRF) spectrometer based on polycapillary X-ray optics was used for the identification of paint layers. The performance of the confocal MXRF was studied. Multilayered paint fragments of a car were analyzed nondestructively to demonstrate that this confocal MXRF instrument could be used in the discrimination of the various layers in multilayer paint systems.

Focal construct geometry for high intensity energy dispersive x-ray diffraction based on x-ray capillary optics

We presented a focal construct geometry (FCG) method for high intensity energy dispersive X-ray diffraction by utilizing a home-made ellipsoidal single-bounce capillary (ESBC) and a polycapillary parallel X-ray lens (PPXRL). The ESBC was employed to focus the X-rays from a conventional laboratory source into a small focal spot and to produce an annular X-ray beam in the far-field. Additionally, diffracted polychromatic X-rays were confocally collected by the PPXRL attached to a stationary energy-resolved detector. Our FCG method based on ESBC and PPXRL had achieved relatively high intensity diffraction peaks and effectively narrowed the diffraction peak width which was helpful in improving the potential d-spacing resolution for material phase analysis.

Annular beam high-intensity X-ray diffraction based on an ellipsoidal single-bounce monocapillary

This short communication presents a study of the use of an annular X-ray beam produced by an ellipsoidal single-bounce monocapillary (ESBC) to perform focal construct geometry (FCG) high-intensity angular-dispersive X-ray diffraction (ADXRD) in transmission mode. The ESBC optic effectively focused a large focal spot X-ray source into a smaller focal spot and produced a narrowed X-ray ring in the far-field pattern when combined with a beam stop. A CCD imaging detector was linearly translated along the principal axis of the ESBC-FCG and obtained the corresponding sequential images of diffraction concentric circular caustics and convergence points, which were formed by the constructive interference of a continuous set of Debye cones arising from the annular interrogation volume. Pixels from the central region of an approximately 0.6u2005mm2 area were interrogated on each sequential image; as a result, a one-dimensional diffractogram of an aluminium oxide sample was revealed. The presented ESBC-FCG ADXRD technique shows potential for increasing the diffracted intensity and streamlining the operation of crystallographic analysis.

Property of slice square polycapillary x-ray optics

A geometrical description of square polycapillary x-ray optics and the basic theory of the transmission of x-rays are presented. A method of numerical calculation is developed based on ray-tracing theory. The method simulates the intensity distribution of x-rays propagating through slice square polycapillary x-ray optics. The simulation results are compared with the experimental results.

Confocal total reflection X-ray fluorescence technology based on an elliptical monocapillary and a parallel polycapillary X-ray optics

A total reflection X-ray fluorescence (TXRF) spectrometer based on an elliptical monocapillary X-ray lens (MXRL) and a parallel polycapillary X-ray lens (PPXRL) was designed. This TXRF instrument has micro focal spot, low divergence and high intensity of incident X-ray beam. The diameter of the focal spot of MXRL was 16.5u202fµm, and the divergence of the incident X-ray beam was 3.4u202fmrad. We applied this TXRF instrument to the micro analysis of a single-layer film containing Ni deposited on a Si substrate by metal vapor vacuum arc ion source.

Confocal three-dimensional micro X-ray fluorescence based on synchrotron radiation for mineral analysis

ABSTRACT The confocal three-dimensional micro X-ray fluorescence using polycapillary optics and a synchrotron radiation was applied to nondestructively analyze elemental compositions of minerals, and thereby obtain the three-dimensional distributions of elements in the minerals. Such confocal micro X-ray fluorescence had potential applications in the mineral prospecting, identification of jades, differentiation of stones.

The Three-Dimensional Elemental Distribution of 3D Printing Stainless Steel Gear via Confocal 3D–XRF Analysis

The macroscopic mechanical properties of 3D printing product are closely related to their microstructure, it has significant importance to accurately characterize the micro-structure of 3D printing products. Confocal three-dimensional micro-X-ray fluorescence (3D-XRF) is a good surface analysis technology widely used to analyse elements and elemental distributions. Therefore, this technique is also very suitable for element distribution measurement of 3D printing product which is printed layer by layer. In this paper the 3D-XRF technique was used to study the spatial elemental distribution of a micro zone from the 3D printing stainless steel gear. An elemental mapping of two orthogonal sections in the depth direction and three dimensional elemental rendering of one micro-region were obtained. The result shows that elemental distribution of the sample is not uniform, the elemental layer structure is formed in the depth direction, the content of the element in measured area vary smoothly, and with no elemental mutation region. This indicates that the 3D printing sample are fused well between layers and layers, with no large pores or bubbles inside the sample. This study demonstrates that it is feasible to make assessment for micro-structure of 3D printing metal product by using confocal 3D-XRF.

Simulation of x-ray transmitted in the square polycapillary x-ray lens

To study the transmission property of the square polycapillary x-ray lens and verify its feasibility using in the x-ray pulsar navigation a geometrical description of it and the basic theory of the transmission of x-rays are presented. A method of numerical calculation is developed based on ray-tracing theory. The method simulates the intensity distribution and calculates the transmission efficiency of x-rays propagating through a square polycapillary lens. The transmission rule of the x-ray propagation in the x-ray lens can be got, after tracing a large number of x-ray beams. A program based on ray-tracing method was designed to simulate the transmission efficiency of an x-ray lens and the light spot gained from it. The transmission property of the square polycapillary x-ray lens is studied based on this program. And the study shows that the transmission property of the square polycapillary x-ray lens is good, and it has the potential of being used in the area of x-ray pulsar navigation.

Energy-dispersive small-angle X-ray scattering with cone collimation using X-ray capillary optics

Energy-dispersive small-angle X-ray scattering (ED-SAXS) with an innovative design of cone collimation based on an ellipsoidal single-bounce capillary (ESBC) and a polycapillary parallel X-ray lens (PPXRL) had been explored. Using this new cone collimation system, scattering angle 2θ has a theoretical minimum angle related to the mean half-opening angle of the hollow cone beam of 1.42 mrad, and with the usable X-ray energy ranging from 4 to 30 keV, the resulting observable scattering vector q is down to a minimum value of about 0.003 Å-1 (or a Bragg spacing of about 2100 Å). However, the absorption of lower energies by X-ray capillary optics, sample transmission, and detector response function limits the application range to lower energy. Cone collimation ED-SAXS experiments carried out on pure water, Lupolen, and in situ temperature-dependent measurement of diacetylenic acid/melamine micelle solid were presented at three different scattering angles 2θ of 0.18°, 0.70° and 1.18° to illustrate the new opportunities offered by this technique as well as its limitations. Also, a comparison has been made by replacing the PPXRL with a pinhole, and the result shows that cone collimation ED-SAXS based on ESBC with PPXRL was helpful in improving the signal-to-noise ratio (i.e., reducing the parasitic background scattering) than ESBC with a pinhole. The cone collimation instrument based on X-ray capillary optics could be considered as a promising tool to perform SAXS experiments, especially cone collimation ED-SAXS has potential application for the in situ temperature-dependent studying on the kinetics of phase transitions.