辐射监测的微弱电流测量I-V转换技术  

An I-V converter in picoampere current measurement

作　　者：魏立乾[1] 雷升杰[2] 方美华[2] 魏志勇[2] 徐波[2] 

机构地区：[1]江苏大学电气学院,江苏镇江212013 [2]南京航空航天大学航天学院,江苏南京210016

出　　处：《仪器仪表与分析监测》2010年第3期28-31,共4页Instrumentation·Analysis·Monitoring

摘　　要：针对辐射测量中电离室输出极其微弱的电流信号,研发一种弱电流测量技术。利用高输入阻抗运算放大器设计了用于微弱电流测量的I-V转换采样电路和带有T型网络的I-V转换采样电路,分析研究了I-V转换电路的特点,计算分析T型网络的I-V转换采样电路的灵敏度。通过T型网络,选用高稳定输入阻抗运算放大器和高稳定反馈电阻,提高了测量灵敏度。设计电路满足辐射粒子所致的电离室输出电流为10-14A数量级时的弱电流测量。very weak current measurement is the key step for the dosimeter,the output current of the ionization chamber is as weak as 10-14A.The input stage of the I-V converter consists of a very high impedance operational amplifier and a high feedback resistance,the input stage converts current to voltage.A T-shaped resistance net is designed for the feedback resistance in the I-V converter circuit.The output voltage and the sensitivity of the I-V converter are simulated.The I-V converter combined with the T-shaped resistance net enhances the sensitivity.The output of I-V converter with T-shaped resistance net,which is in the order of magnitude of mV,is processed by the following units of an amplifier and filters,the final signal will be in the order of magnitude of V and could be digitized for record.I-V converter is stable and makes the dosimeter compact and low-weight.

关 键 词：弱电流测量 I—V转换 T型网络 运算放大器 辐射剂量 

分 类 号：TP202.3[自动化与计算机技术—检测技术与自动化装置] TM933.1[自动化与计算机技术—控制科学与工程]