Analysis of geometric factors for an X-ray fluorescence analyzer designed via the Monte Carlo method

Hefan Liu,Xiang Hu,Laidong Zhou,Zihang Zhou,Chengwei Lu,Hong Tian,Guoqiang Zeng,Fengxia Huang,S.A Hamouda,Z Yu,M Mirzaei

doi:10.1051/matecconf/20166101008

Abstract

This paper presents a theoretical study on the design of an X-ray fluorescence (XRF) analyzer. The relative geometric positions of the analyzer’s source, detector and specimen are emphasized, which impacts the analyte’s characteristic X-ray fluorescence counts. The theoretical formula for the X-ray fluorescence intensity was derived. The geometric factors (angle and distance) were simulated using Monte Carlo Neutron-Particle Transport Code MCNP5. The Cu’s X-ray characteristic peak counts were calculated. These Monte Carlo model calculations analyzed two types of geometry changes. The best geometric positions for the XRF analyzer had the incident angle for the excitation source (β) equivalent to the exit angle for the specimen’s characteristic X-ray (β). The maximal characteristic X-ray peak counts were obtained when α and β were orthogonal, and the minimum counts were obtained when parallel. To increase the fluorescence counts, the source and detector should be set as close to the specimen as possible. This method and these conclusions can provide technical guidance for designing XRF analyzers.

Highlights

X-ray fluorescence (XRF) analyzers are one of the most important analytical instrument types for element analyses [1,2,3,4,5,6]
The best geometric conditions were obtained by varying the geometric parameters for the XRF analyzer design via the Monte Carlo method
Many models to determine the influence of different geometric factors and XRF fluorescence counts have been established in this paper

Summary

Instruction

X-ray fluorescence (XRF) analyzers are one of the most important analytical instrument types for element analyses [1,2,3,4,5,6]. The analyte’s characteristic X-ray fluorescence counts relate to its physical and chemical properties and the geometric positions of the source, specimen and detector [7,8,9]. Many methods are used to find the optimal geometric conditions when designing XRF analyzers. The Monte Carlo Neutron-Particle Transport Code MCNP5, produced by Los Alamos National Laboratory, is important software for nuclear analysis including simulating and calculating XRF spectroscopy [10]. The best geometric conditions were obtained by varying the geometric parameters for the XRF analyzer design via the Monte Carlo method

Theoretical calculations

Angle descriptions

Basic model

Findings

Impact of distance

Conclusions