中子成像的氢散射校正方法  

Hydrogen Scattering Correction Method for Neutron Imaging

作　　者：游绍初 贺林峰[1] 武梅梅[1] 李正耀 阮世豪 王天韵 陈东风[1] YOU Shaochu;HE Linfeng;WU Meimei;LI Zhengyao;RUAN Shihao;WANG Tianyun;CHEN Dongfeng(China Institute of Atomic Energy,Beijing 102413,China)

机构地区：[1]中国原子能科学研究院,北京102413

出　　处：《原子能科学技术》2024年第10期2198-2204,共7页Atomic Energy Science and Technology

基　　金：国家自然科学基金委联合基金(U2241282)。

摘　　要：中子成像可无损地探测样品内部的成份和结构等信息,已应用于诸多领域中材料的定量分析。中子成像对样品中的含氢物质进行定量分析时,由于氢的总散射截面大于吸收截面,散射中子会降低图像质量,严重干扰定量分析。已有的散射校正方法各自存在一定的局限性,或不适用所有样品、或增加曝光时间或数据处理复杂等。因此,本文提出了一种新的散射校正方法—双探测器法,并对水层样品进行实验验证。结果表明,校正后的水层厚度与实际厚度基本一致,验证了双探测器法是一种可行的散射校正方法。Neutron imaging can nondestructively detect the composition and structure of a sample,and has been used in many fields for quantitative analysis.Neutron imaging can be used to detect elements that are difficult to detect with X-rays,such as hydrogen.When neutron imaging is used for quantitative analysis of hydrogen-containing samples,the neutron beam decays because of scattering with hydrogen rather absorption.However,neutrons scattered in the direction of the neutron beam may still reach the detector,and these scattered neutrons can bring additional intensity to the sample and its edges,bring artifacts to the image,and cause serious interference to quantitative analysis.The elimination of scattering effect is one of the most important problems in the quantitative analysis of neutron imaging.Because samples with hydrogen have a larger total scattering than absorption cross section,the influence of the scattered neutrons on the transmitted image is not negligible.The results of neutron imaging quantitative analysis are also affected by the energy spectrum effect.Since the incident neutron beam is not unienergetic,the probability of interaction between the lower energy neutrons and the sample is high,resulting in the macroscopic cross section of the neutron varying with the thickness of the sample.Several existing scattering correction methods,such as increasing the distance between the sample and the detector,the point scattered functions method,using microchannel plates,and using the blackbody grids,are not applicable to all samples,or not applicable to dynamic neutron imaging,or will increase exposure time or complicate data processing.A new scattering correction method,the doubledetector method was presented.The double-detector method used two detectors at two locations to image.The close detector can obtain a high-resolution image,but the image is affected by scattered neutrons.The far detector obtain images that are unaffected by scattered neutrons,but with poor resolution.The scattering neutron distribution

关 键 词：中子照相 定量分析 散射校正 能谱硬化 

分 类 号：TL99[核科学技术—核技术及应用]