基于整体毛细管会聚透镜在氦气环境下的X射线荧光技术  

X-Ray Fluorescence Technology Based on Monolithic Polycapillary X-Ray Focusing Lens in Helium Atmosphere

作　　者：李惠泉 孙学鹏 邵尚坤 袁天语 华陆 钟玉川 刘志国[1,2] 孙天希 LI Hui-quan;SUN Xue-peng;SHAO Shang-kun;YUAN Tian-yu;HUA Lu;ZHONG Yu-chuan;LIU Zhi-guo;SUN Tian-xi(Key Laboratory of Beam Technology of the Ministry of Education,College of Nuclear Science and Technology,Beijing Normal University,Beijing 100875,China;Institute of Radiation Technology,Beijing Academy of Science and Technology,Beijing 100875,China)

机构地区：[1]北京师范大学核科学与技术学院,射线束技术教育部重点实验室,北京100875 [2]北京市科学技术研究院辐射技术研究所,北京100875

出　　处：《光谱学与光谱分析》2024年第8期2198-2201,共4页Spectroscopy and Spectral Analysis

基　　金：国家重点研发计划“基础科研条件与重大科学仪器设备研发”重点专项(2021YFF0701202);国家自然科学基金项目(12105020);北京市科学技术研究院创新工程、创新培育项目资助。

摘　　要：当X射线荧光(XRF)技术被用于分析空气环境中样品的元素组成时,由于空气对低原子序数(Z)元素(如Cl、K、Ca等)中能量较低的特征X射线吸收较大,从而影响探测效果,因此为了避免空气对低Z元素特征X射线的吸收,经常采用真空条件下XRF技术,但它需要复杂昂贵的真空系统。另外,一般实验室光源功率较低,所以入射光强度较弱,从而也影响探测效果。为解决上述这些问题,设计了基于整体毛细管X射线透镜(PCXRL)和转靶光源并在氦气环境下的密闭XRF简易分析系统。利用透镜聚焦获得的高功率密度增益X射线照射样品,获得较强的XRF信号,并使激发通道和探测通道处于稳定的氦气环境,以降低空气对低Z元素特征X射线的吸收。通过实验对整个XRF分析系统进行了表征,然后测定了互花米草、盐地碱蓬样品。研究表明,在氦气环境中,利用旋转钼靶光源并使工作电压和电流分别为29 kV和20 mA的条件下,所探测到的Cl、K、Ca、Fe等元素特征峰强度高于空气环境下的强度,针对植物中X射线特征峰能量低于8 keV的元素而言,在氦气环境中探测到的特征峰强度为空气中的1.1~5.5倍。这有利于高效无损分析样品中的低原子序数元素成分。When X-ray fluorescence(XRF)is used in analyzing the element composition of the sample in air atmosphere,the strong absorption from the air to the low-energy characteristic X-rays from such low atomic number(Z)elements as Cl,K,Ca,and so on,deeply affect the analysis for them.To avoid the strong absorption from the air to the characteristic X-ray of low Z elements,the XRF technology in a vacuum atmosphere is often used,but it requires a complicated and expensive vacuum system.Besides,the power of the laboratory source is generally low.This results in a low intensity of incident X-rays,which also affects the analysis of the element composition of the sample with XRF.To solve the above problems,a simple closed XRF analysis system in a helium atmosphere based on a monolithic polycapillary X-ray lens(PCXRL)and rotating target X-ray source was designed.Strong XRF signals were obtained by using X-rays with a high gain of power in density focused by the PCXRL to irradiate the sample,and the excitation channel and the detection channel were both in a stable helium atmosphere to reduce the absorption from the air to the characteristic X-rays of low Z elements.The designed XRF system was characterized to show that with a rotating molybdenum target working at a voltage of 29 kV and a current of 20 mA,the detected XRF intensity of Cl,K,Ca,and Fe in a helium atmosphere is higher than that in an air atmosphere,respectively.For elements with an energy of the characteristic XRF below 8 keV in plants,the characteristic XRF intensity detected in the helium atmosphere is 1.1 to 5.5 times that in the air.This is helpful for an efficient and non-destructive XRF analysis of the elements with low Z of samples.

关 键 词：X射线荧光 整体毛细管X射线会聚透镜 氦气 无损分析 

分 类 号：O434.1[机械工程—光学工程]