基于X射线透射成像及荧光双模式的珍珠检测  

Identification of Pearl Based on X-Ray Transmission Imaging and Fluorescence Dual Mode

作　　者：邵尚坤 孙学鹏 杜晓光 李玉飞 王亚冰 张晓芸 刘志国[1,2] 孙天希[1,2] SHAO Shang-kun;SUN Xue-peng;DU Xiao-guang;LI Yu-fei;WANG Ya-bing;ZHANG Xiao-yun;LIU Zhi-guo;SUN Tian-xi(Key Laboratory of Beam Technology of Ministry of Education,College of Nuclear Science and Technology,Beijing Normal University,Beijing 100875,China;Beijing Radiation Center,Beijing 100875,China;Beijing Division,China Nuclear Power Technology Research Institute,Beijing 100086,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]北京市辐射中心,北京100875 [3]中广核研究院有限公司北京分公司,北京100086

出　　处：《光谱学与光谱分析》2020年第12期3936-3940,共5页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(11675019,11875087)资助。

摘　　要：针对常规珍珠检测方法需要检测者具有丰富的经验、样品预处理、破坏样品、检测时间长等问题,设计了一种基于X射线透射成像及荧光双模式的珍珠检测系统。该系统首先通过在X射线透射成像系统上加入测厚系统,引入样品厚度进行修正,可以计算X射线在物质中的衰减系数,这就使得对于X射线吸收相同,厚度不同,衰减系数相近的样品也可以分辨出来,提高了成像系统的分辨,通过大量样品的测量建立衰减系数阈值数据库,根据衰减系数与阈值的对比,实现不同仿珍珠之间、珍珠与仿珍珠之间的鉴别;然后利用衰减系数相近的淡水和海水珍珠Ca元素含量远大于Sr元素,且淡水和海水珍珠中Sr含量不同,可以使用Sr和Ca元素含量的比值不同来区分淡水和海水珍珠,因此引入X射线荧光分析系统测量淡水和海水珍珠中Sr和Ca的荧光强度比,通过大量样品测量计算区分淡水和海水珍珠的荧光强度比的阈值,根据测量值和阈值的对比,从而进行淡水和海水珍珠的鉴别。引入测厚系统的X射线透射成像系统和X射线荧光检测系统协同运行,构成了鉴定珍珠的双模式系统。实验结果证明:该双模式系统可以在不破坏样品的前提下对不同仿珍珠之间、珍珠与仿珍珠、淡水与海水珍珠之间进行鉴别。该双模式检测系统在配合分拣系统后可以实现对大量样品的在线检测,带有分拣系统的双模式检测系统在珠宝鉴定、矿石检测、石制地板检测等领域具有潜在应用。In order to solve the problems of conventional pearl identification methods,which require the testing personnel to have rich experience,sample pretreatment,sample destruction and long detection time,a dual-mode pearl detection system based on X-ray transmission imaging and fluorescence was designed.X-ray attenuation coefficient could be calculated by the introduction of a thickness measurement system on X-ray transmission imaging system.The attenuation coefficient of the material can be calculated,which makes samples with the same X-ray absorption,different thickness and similar attenuation coefficient can be distinguished,and the resolution of the imaging system can be improved.The thresholds database of attenuation coefficients was established by measuring a large number of samples.By comparing the attenuation coefficient with the threshold value,the identification between different imitation pearls,pearls and imitation pearls could be realized.The content of Ca in freshwater and seawater pearls with similar attenuation coefficients is much larger than that of Sr,and the content of Sr in freshwater and seawater pearls is different.The ratio of contents of Sr and Ca be used to distinguish between freshwater and seawater pearls.Therefore,X-ray fluorescence analysis system is introduced.The fluorescence intensity ratios of Sr and Ca in fresh water and seawater pearls were measured,and the threshold value of the fluorescence intensity ratio between freshwater and seawater pearls was calculated by a large number of sample measurements,and the identification of freshwater and seawater pearls was performed based on the comparison between the measured values and the threshold values.The X-ray transmission imaging system and the X-ray fluorescence system introduced into the thickness measurement system cooperate to form a dual-mode system for identifying pearls.The experimental results show that the dual-mode system can distinguish between different imitation pearls,pearls and imitation pearls,freshwater and seawater pe

关 键 词：X射线荧光分析 X射线衰减系数 珍珠 双模式系统 

分 类 号：O434.13[机械工程—光学工程]