基于低温电流比较仪的微弱电流精密测量技术  

Low current precision measurement technique based on cryogenic current comparator

作　　者：鲁云峰[1,2] 赵建亭[2] 贺青[2] 张钟华[2] 

机构地区：[1]哈尔滨工业大学电气工程及自动化学院,哈尔滨150001 [2]中国计量科学研究院,北京100013

出　　处：《仪器仪表学报》2013年第12期2812-2817,共6页Chinese Journal of Scientific Instrument

基　　金：国家自然科学基金(51107129;51107109);国家科学仪器设备开发专项(2011YQ09004)资助项目

摘　　要：研制了基于dc-squid(dc-superconducting quantum interference devices)的低温电流比较仪,通过实验及分析,其电流分辨率为7.1 fA/Hz1/2,比例误差小于10-11量级,将该低温电流比较仪应用于微弱电流精密测量,通过溯源到量子化霍尔电阻的1 kΩ标准电阻以及校准过的数字电压表对低温电流比较仪放大后的副边电流进行测量,进而构成微弱电流精密测量系统,实现微弱电流的精密测量,对于(1～10)μA的电流测量,理论标准不确定度小于1×10-8,最高可达到1×10-9;利用该测量系统对目前商用最好的微电流源表进行初步测量,其灵敏度远远高于源的稳定性,完全满足目前nA级以上微弱电流精密测量要求。A cryogenic current comparator based on dc-direct superconducting quantum interence devices （dc- SQUID） was designed. The experiment and analysis show that the ratio error of the cryogenic current comparator is below 10 and the current resolution is 7.1 fA/Hzj/2. The cryogenic current comparator was applied to low current precision measurement. A 1 kf~ standard resistor traced to the quantum hall resistance and a calibrated digital voltme- ter were used to measure the amplified secondary side current of the CCC,which forms a low current precision meas- urement system and the accurate measurement of low current is realized. The theoretical standard uncertainty of the system is below 1 × 10^- 8 and reaches 1 × 10^-9 at most in the current measurement of （1 -10）μA. The measurement system was used to measure the best commercial current source meter in a simple experiment;the result shows that the sensitivity of the measurement system is much better than the stability of the current source, which can completely meet the requirement of low current precision measurement above nA level.

关 键 词：低温电流比较仪 dc—SQUID 量子化霍尔电阻 微弱电流测量 比例误差 

分 类 号：TB971[一般工业技术—计量学]