基于自生磁场约束效应的脉冲调制X射线源用转换靶

Conversion Target for Modulated Pulse X-ray Source Based on Self-Generated Magnetic Field Confinement Effect

提出了一种基于自生磁场约束效应的调制X射线源结构设计方案,采用蒙特卡罗方法模拟计算了几种后端X射线转换靶常见靶材(铬、镍、铜、铑、钯、银、镉、钨、金),不同转换靶厚度下的X射线产额;计算了在最佳靶厚情况下的X射线能谱、空间角度分布及焦点大小;针对单色X射线的应用背景,计算了几种常见靶材条件下,不同转换靶厚度对应的特征X射线的产额和特征信噪比大小。计算结果表明,基于自生磁场约束效应的调制X射线源具有调制速率快、光子产额高及焦斑尺寸小等优点,结合单色晶体使用,可获得强度高及单色性好的X射线。

In this paper,a structural design scheme of modulated X-ray source based on self-generated magnetic field confinement effect is proposed.The characteristic X-ray yields of conversion targets with different thickness are simulated by Monte Carlo method when several common target materials,such as Cr,Ni,Cu,Rh,Pd,Ag,Cd,W,Au,are used as back-end X-ray conversion targets.The characteristic X-ray energy spectra,the spatial angle distribution,and the size of focus at the optimum conversion target thickness are calculated.According to the application background of monochromatic X-rays,the yields and the characteristic signal-to-noise ratio(CSNR)corresponding to different conversion target thickness of several common target materials are calculated.The results show that the modulated X-ray source based on the self-generated magnetic field confinement effect has the advantages of fast modulation rate,high photon yield,and small focal spot size.Combined with monochromatic crystals,X-rays with high intensity and good monochromaticity can be obtained.