The Research And Development Of Multi-Channel Energy Dispersive X-Ray Fluorescence Analyser

X-ray fluorescence analysis is a method for chemical elements’ qualitative and quantitative analysis. In the early 1970s, energy dispersive X-ray fluorescence spectrometer entered the ranks of the instrumental analysis formally and became an important nuclear analytical tool, besides it is used widely in geology, metallurgy, petrochemical, criminal investigation, archeology, the semiconductor industry, the medical and other fields.Energy resolution is an important indicator of detecting the performance of energy dispersive X-ray fluorescence spectrometer. It is not only related to the resolution of the detector, but also concerned with the performance of the circuit. In order to improve the energy resolution of the instrument, a built-in pre-amplifier semiconductor detector of Amptek’s XR-100CR is adopted in the design, the energy resolution of which can reach 145eV. In the design of the subsequent circuit, the energy resolution of the instrument can be improved by optimizing the main amplifier circuit and the peak hold circuit. Stability is also considered as an important indicator of the instrument, which includes the stability of circuits and communication. In order to ensure the stability of the instrument, some anti-interference settings are added in the circuit design. In order to ensure the stability of communication, handshake signals are adopted in the communication between the host computer and the lower machine.In this paper, the excitation source of multi-channel energy dispersive X-ray spectrometer adopts the domestic X-ray tube, and the target’s material is Mo. The best range of fluorescence excitation is determined based on the features of the X-ray tube. Besides, the hardware circuit is developed based on FPGA, and the interactive interface is designed with Lab Windows/CVI. The hardware circuit includes the signal conditioning module, the analog-digital convert module, the FPGA control module, the digital-analog convert module and the communication module. The functions of the interactive interface include controlling the lower machine to be on or off, reading the data, plotting the spectrum and optimizing the spectrum. Finally, a test of the instrument is conducted, the results of which show that desired purpose is achieved, and the detection range, the energy resolution and the stability have been improved.