基于NaI晶体的车载γ能谱采集系统研制  

Design of An Vehicle MountedγEnergy Spectrum Acquisition System Based on Sodium Iodide Crystals

作　　者：王先贺 吴伟军 刘金尧 陈元庆 黄清波[1] WANG Xianhe;WU Weijun;LIU Jinyao;CHEN Yuanqing;HUANG Qingbo(Airborne Survey and Remote Sensing Center of Nuclear Industry,Shijiazhuang,Hebei 050000,China)

机构地区：[1]核工业航测遥感中心,河北石家庄050000

出　　处：《铀矿地质》2024年第3期540-546,共7页Uranium Geology

摘　　要：针对我国辐射环境监测、核应急、放射性地球物理勘查等特殊领域的应用要求,研制了一种基于NaI晶体的车载γ能谱采集系统。文章采用NaI晶体探测器将γ射线信号转换为电脉冲信号,设计了前置放大、极零相消、S-K滤波成形、增益调节等调理电路,对NaI晶体探测器原始信号进行了处理,得到了准高斯波形;然后通过多道脉冲幅度分析器对脉冲信号数字化处理得到谱数据;最后开发了一套上位机分析软件来对谱数据进行分析、处理以及显示,实现了数据捕获、能量刻度、核素识别以及谱线显示等功能。为解决现有车载γ能谱仪分辨率低、谱线漂移的问题,文章提出了一种自动无源稳谱算法改善了车载γ能谱仪的能量分辨率和能量线性度,提高了测量数据的准确度。实验结果表明:该设备可以准确快速地进行能谱分析,具有1024道的高分辨率,能量分辨率达到8.06%(137Cs),对40K的1.461 MeV能谱峰漂不超过±1道,并具有测量速度快、探测精度高、实时定位等优势,在核应急与核辐射环境监测以及放射性勘查等领域具有广泛的应用前景。To meet the special application requirements in the fields of radiation environment monitoring,nuclear emergency,and radioactive geophysical survey in China,the article developed a vehicle-mountedγenergy spectrum acquisition system based on NaI crystal.The system uses the NaI detector to convert theγ-ray signal into an electrical pulse signal,and conditioning circuits such as pre-amplification,pole-zero phase cancellation,S-K filter shaping,gain adjustment,and so on,was designed to process the original signal of the NaI detector and obtained a quasi-Gaussian waveform;then the spectral data were obtained by digitizing the pulse signal through a multi-channel pulse amplitude analyzer;after then,a set of upper computer analysis software was developed to analyze the spectral data.Finally,a set of upper computer analysis software was developed to analyze,process and display the spectral data,which realized the activity measurement,real-time nuclide identification and digital spectroscopy.In order to solve the problems of low resolution and spectral drift of the existing vehicle-mountedγ-energy spectrometer,an automatic passive stabilization algorithm was proposed to improve the energy resolution and the linearity of the vehicle-mountedγ-energy spectrometer,which improved the accuracy of the measurement data.The experimental results showed that the device can accurately and rapidly carry out energy spectrum analysis and radioactivity detection,with a high resolution of 1024 channels,energy resolution of 8.06%(137Cs),and the peak drift of the 1.461 MeV energy spectrum of 40K is not more than±1 channel,and has the advantages of fast measurement speed,high detection accuracy,real-time positioning,etc.,which are need in the field of nuclear emergency response and nuclear radiation environmental protection.Therefore,the designed system has a wide range of application prospects in the field of nuclear emergency and nuclear radiation environmental protection.

关 键 词：放射性地球物理勘查 车载γ能谱采集 多道脉冲幅度分析器 自动无源稳谱 

分 类 号：TL817.2[核科学技术—核技术及应用]