Ding Xunliang

An investigation of X-ray fluorescence analysis with an X-ray focusing system (X-ray lens)

Abstract Divergent X-ray radiation has been focused into a small spot (diameter 500 μm) by an X-ray lens made of polycapillaries, increasing the power density by 10 4 times. The new X-ray lens has been applied to the XRF technique. Limits of detection of 10 −9 −10 −10 g have been obtained by means of the new technique with an X-ray tube of 2 W power.

X-ray attenuation coefficients and photoelectric cross sections of Cu and Fe in the range 3 keV to 29 keV☆

Abstract A new X-ray source has been obtained by proton excitation of elemental or compound targets. Using this X-ray source and Si(Li) detector system the mass attenuation coefficients have been determined for copper in the energy range 3.3–29.1 keV, for iron in 3.3–20 keV. The experimental uncertainties of the attenuation coefficients have been reduced to ±1% for intense isolated characteristic X-rays. The total photoelectric cross sections have been obtained by subtracting scattering cross sections from the measured total cross sections. The comparisons of the present experimental results with the past values, as well as between the experimental values and the theoretical calculations, have been presented and discussed.

Investigation of a Tabletop Confocal Micro X-Ray Fluorescence Setup

A new tabletop confocal micro x-ray fluorescence setup with an MCBM 50-0.6B x-ray tube is assembled. The confocal micro x-ray fluorescence setup includes two lenses, a polycapillary full lens in the excitation channel and a polycapillary half lens in the detection channel. A Ni-Cr wire in diameter 25 μm is used to investigate the FWHM of three-dimensional confocal volume. A basso-relievo capital letter of a 1-jiao RMB coin of 2005 version is studied with this confocal micro x-ray fluorescence setup.

Measurements of mass attenuation coefficients of yttrium with characteristic lines from elements excited by energetic protons

Abstract The characteristic X-rays from elemental or compound targets excited by a proton beam of tandem accelerator is a quasimonochromatic X-ray source. The mass attenuation coefficients of yttrium have been systematically measured in the region 3.3 keV to 29.1 keV by using this kind of X-ray source. The experimental uncertainties of mass attenuation coefficients have been reduced to ±1%. The coherent scattering cross sections have been calculated in accordance with the present experimental condition. The total photoelectric cross sections have been obtained by subtracting scattering cross section from the measured total cross sections.

Mass attenuation coefficients for elements measured with characteristic x-rays from targets excited by energetic proton

The characteristic x-rays from elemental or compound targets excited by energetic proton are quasi-monochromatic x-ray sources. The advantages of high line/background ratio, controllable intensity as well as many available energies, make them suitable for applications in many important fields. The total mass attenuation cross sections of yttrium have been systematically measured by using this kind of x-ray source. The accuracy of experimental data has been improved to ± 1%, which is much better than that of earlier results. The contributions of the coherent and incoherent scattering cross sections have been calculated in accordance with the present experimental condition. And the total photoelectric cross sections have been obtained by subtracting the scattering cross section from the measured total cross sections. The comparisons of our experimental results with the available data of earlier investigations as well as with the theoretical calculations have been presented and discussed.

A study of the chemical driving force in ion mixing of metal-metal systems

Abstract The thermal chemical effect in ion mixing of metal-metal systems was studied experimentally and through computer simulation. Sandwich systems of Cu/Ag/Cu, Cu/In/Cu and Cu/Sb/Cu were irradiated by 200 keV Krionsatliquid nitrogen temperature at doses from 1 to 6 × 1015 cm−2. The experimental results reveal that the chemical driving force plays an important role in these systems. Taking into account the chemical driving force, a simple model of ion mixing has been developed using the Monte Carlo code TCIS-4.

The structural and electrical properties of ion-beam mixed tungsten silicides

Abstract The factors affecting the structural and electrical properties of ion beam induced WSi2 films have been studied by combined techniques. It is found that the formation temperature of the refractory tungsten silicide can be significantly reduced by elevated substrate temperatures during implantation. The change in the resistivity of the film after annealing is related to the microstructure. Oxygen impurities present in the film limit the grain growth resulting in smaller grains and higher resistivity. The redistribution of oxygen and implanted As ions during annealing was observed. A significant portion of the implanted As is lost from the surface after annealing at higher temperatures. Finally, the mechanism of the silicide formation by ion beam mixing is briefly discussed.