硬X射线微束掠入射实验的控制和数据采集系统及其应用

doi:10.3964/j.issn.1000-0593(2019)09-2794-06

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Abstract The hard X-ray micro-beam grazing incidence experimental method has been first developed in China. This method with micro-spatial resolution is applied to analyze nano-thickness films in micro-regions. It is greatly significant for analyzing the uneven component, structure, thickness, roughness and chemical valence of surface elements in micro-regions. In this work, according to the principle of X-ray total reflection technology, and based on the high-flux, energy-adjustable monochromatic micro-beam X-rays, a control and data acquisition system of the grazing incidence experimental method is designed, which integrates motion control, light intensity detection, diffraction and fluorescence detection. This system adopts the distributed control system structure, and designs the SPEC control software based on the Experimental Physics and Industrial Control System (EPICS) environment. By establishing the access channels of SPEC and EPICS, it realizes using SPEC software to control the equipment on the EPICS platform. Regarding the designed control and data acquisition system, the motion control system controls multi-dimensional sample stage motors, and it can position the sample and adjust the grazing incidence angle. The light intensity detection system detects the intensity of the emitted light of the sample. Motion control and light intensity detection system are combined to realize sample stage scanning positioning. Diffraction and fluorescence detection system can obtain diffraction peak intensity and fluorescence counts of the sample at different incident depths. Additionally, in order to locate an accurate zero-angle position where the sample plane is parallel to the X-ray, a method of automatic controlling zero-angle is given, its control algorithm is programmed and it realizes automatic and accurate zero-angle positioning. Revealed by zero-angle scanning positioning results, the spatial resolution of the experimental system is 2.8 μm, and the zero-angle positioning accuracy is below ±0.01°. Finally, micro-beam grazing incidence X-ray diffraction and fluorescence experiments with automatic and accurate control of zero-angle have been first performed by using this experimental system at the micro-focusing beamline of Shanghai Synchrotron Radiation Facility. The sample was a 10 nm Au/Cr/Si thin film, the uppermost layer of the Si substrate was a 10 nm thickness Au thin film, and there was a very thin layer of Cr adhesion between them. Diffraction signals of the sample were measured at different grazing incidence angles and diffraction peak intensity could be obtained. Fluorescence counts were also collected at the same grazing incidence angles. Thereby the phase structure information and the relationship of fluorescence counts and incidence angles were obtained. This experimental system realizes the analysis of phase structure and composition of nano-thickness films in micro-regions. Additionally, according to the maximum value of fluorescence counts, an incident angle can be selected at which grazing incidence X-ray absorption near-edge structure experiments can be developed for low-concentration samples, and it is helpful to improve the signal-to-noise ratio of this experimental method.

Key words：Micro-beam grazing incidence; Diffraction; Fluorescence; High spatial resolution

Received: 2018-07-20 Accepted: 2018-12-05

ZTFLH:

O434.1

Corresponding Authors: HE Shang-ming E-mail: heshangming@sinap.ac.cn

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https://www.gpxygpfx.com/EN/10.3964/j.issn.1000-0593(2019)09-2794-06 OR https://www.gpxygpfx.com/EN/Y2019/V39/I09/2794