一种用于辐射测量的电荷放大器设计  

Design of charge integration amplifying circuit for radiation-measuring

作　　者：钱承 李诺 QIAN Cheng;LI Nuo(China National Accreditation Service for Conformity Assessment,Beijing 100062,China;Electronic Institute,Liaoning Provincial Institute of Measurement of China,Shenyang 110004,China)

机构地区：[1]中国合格评定国家认可中心,北京100062 [2]辽宁省计量科学研究院,辽宁沈阳110004

出　　处：《中国测试》2023年第2期139-143,共5页China Measurement & Test

基　　金：原辽宁省质量技术监督局科技计划项目(2013606);辽宁省自然科学基金指导计划项目(2019-ZD-0864)。

摘　　要：为解决辐射测量传感器输出电流难以准确采集的问题,该文设计并实现一种pA级电流放大器。首先对放大器的低频截止点、高频截止点、噪声特性和漂移等关键指标进行分析,基于电容积分原理设计一种用于pA级电流采集的电荷放大器,并从施加等电位屏蔽、提高绝缘性能、应用相位补偿和抑制噪声四个方面对放大器的性能进行优化,以确保其输出稳定可靠。最后,在多功能校准源Fluke 5720A、标准分压器和标准电阻箱辅助下,将该放大器的输出结果与Keithley 6514的测量结果进行比较,确定该放大器的测量准确度优于1%。并对该放大器的改进方向进行阐述。该放大器已被用于局部放电量在10 pC及其以下的校正脉冲发生器校准中,并取得良好的效果。In order to solve the micro-current sample problem whose value is less than 1μA,a pA level current amplifier is designed and implemented in this paper.First the basic design principle and its calculation formulas such as low cut-off frequency,high cut-off frequency,noise characters and drift characters are analyzed,and a charge amplifier used for measuring pA level current is designed with capacitor integration method,and then in order to ensure its output is stable and reliable,four aspects such as applying equipotential shielding,enhancing insulation performance,compensating the phase and suppression noise are used for optimizing the performance of the amplifier.Finally,with the assistance of Fluke 5720A,standard voltage divider and standard resistance box,the results of the amplifier are compared with the measurement results of Keithley 6514,and the measurement accuracy of the amplifier is determined to be better than 1%.In the conclusion section,the work of dissertation is summarized and prospect of improving direction of system is presented.At present,the amplifier has been used in calibrating the standard pulse generators whose discharge power is below 10 pC and has achieved good results.

关 键 词：微小电流测量 辐射测量设备 地环技术 绝缘技术 相位补偿 噪声抑制 局部放电(PD) 

分 类 号：TB9[一般工业技术—计量学] TH714.8[机械工程—测试计量技术及仪器]