井下NaI晶体探测器模拟前端电路的研究  

Study on front-end analog circuit for down-hole NaI scintillation detector

作　　者：王辉[1] 庞希顺[1] 尚修盛[1] 

机构地区：[1]中海油田服务股份有限公司油田技术事业部,三河065201

出　　处：《电子测量技术》2015年第4期132-135,共4页Electronic Measurement Technology

摘　　要：为提升NaI晶体探测器在井下应用时信号调理的可靠性,降低脉冲幅度亏损,提高信噪比和抗过载能力,提出了一种适用于井下应用的NaI晶体探测器模拟前端电路的设计。通过对NaI晶体探测器光电转换信号模型进行分析,结合石油测井应用中对γ光子脉冲幅度分析的技术要求,采用电荷前置放大器配合高精度温度传感器,基线恢复器,脉冲幅度放大器,低通Sallen-Key滤波器构建精练电路,实现了模数（ADC）转换前0～4.5V范围内精密准高斯脉冲信号成形。经实验测定,脉冲信号成形后信号通过率大于300 kHz,脉冲展宽约6μs左右,可有效提升井下γ射线能谱分析的可靠性、精确性。In order to enhance the reliability of signal regulation, reduce amplitude error, improve the SNR and the anti overload ability, puts forward the design of a front-end analog circuit suitable for the NaI scintillation detector in down- hole application. Through the analysis of converted signal model of NaI scintillation detector and combined with the technical requirements for the well logging application of gamma photons pulse amplitude analysis, adopting charge preamplifier with high precision temperature sensor, baseline restorer, pulse amplitude amplifier and Sallen-Key filter to structure the concise circuit, to achieve the precision wavelorm of quasi Gauss pulse signal before analog to digital eonversion（ADC）. Measured by the experiment, the forming of nuclear pulse signal through rate is greater than 300 kHz, pulse width is about 6 μs can effectively improve the reliability and accuracy of down-hole gamma ray spectrum analysis.

关 键 词：NaI晶体探测器 电荷前置放大器 低通Sallen-Key滤波器 脉冲幅度分析 

分 类 号：TN784[电子电信—电路与系统]